Chemical Reactions for Kids to Explore

chemical-reactions-for-kids

We’ve just completed a three-week series on Chemistry, starting with States of Matter, then Mixtures and Solutions, and then Reactions.

Here’s how we described the big picture of chemical reactions to the kids in class (age 3 – 7): When some chemicals mix together, they “react” and the substances change in some way. Some of the signs of a chemical reaction are changes in color, texture, shape, or smell, or the mixture becomes warm or cold, or it makes sound, light, or bubbles.

Discovery Time: For the first 25 minutes of class, we wanted them to experience reactions, before we explained them in opening circle. So, we started with some hands-on fun. (For a bigger version of any of the images, just click on it for a closer look.)

Jar of Bubbling Goo (Vinegar, Baking Soda, and Oil): This is really cheap and simple, yet really dramatic – check out the video on YouTube! Some of our students loved this so much they wanted to do it over and over.

Prep baking soda ice cubes: Use water, baking soda and blue food coloring to make a thin paste. Freeze in ice cube trays.

At class: Take a jar. Pour in one inch of white vinegar, two inches of vegetable oil, and a few drops of yellow or red food coloring. Point out that the oil and vinegar don’t mix, and that the food coloring doesn’t affect the oil – this is a flashback to last week’s class and immiscible liquids. Then drop in a baking soda ice cube. Sit back and observe. As the baking soda and vinegar react, they release lots of bubbles that rise up through the oil, pop and sink back down. It looks sort of like molten lava bubbling. When the reaction stops, add more vinegar and another ice cube, or start a new jar.

Note, since the photo shows a lid…. you can set a lid on top of the jar but don’t screw it down – you want the gas to be able to escape, not build up pressure.

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Lava Lamps.” Another bubbling bottle activity (we did it last week…) is to pour oil, water, and food coloring into a jar or water bottle.Then add an alka seltzer tablet. Here’s how Steve Spangler describes the science of what happens: “the Alka-Seltzer tablet reacts with the water to make tiny bubbles of carbon dioxide. These bubbles attach themselves to the blobs of colored water and cause them to float to the surface. When the bubbles pop, the color blobs sink back to the bottom of the bottle.” It’s infinitely re-useable. Any time you want more bubbles, just add another Alka-Seltzer. If you don’t have Alka-Seltzer, Hands On As We Grow says salt works too.

Fizzing Powder: Fill a shallow tray with baking soda. Then mix liquid watercolors with vinegar. Let the children use pipettes, eye droppers, turkey baster, or spray bottles to drip colored vinegar on the baking soda and watch it fizz. (Note: we tried taking coffee filter prints of the product, but it wasn’t a very interesting art project, so we decided to just leave it as the basic tray of fizzy powder activity.) See more pictures of this at Hands on as we grow and Creatively Blooming.

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This is simple, cheap, easy to clean up, a great exposure to chemical reactions, a fun art process activity, and great small motor practice.

Self-Inflating Balloon – Blow up a balloon with a chemical reaction.

  1. Pour one inch of vinegar into an empty water or soda bottle.
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  2. Then spoon a small amount of baking soda into a balloon. (Optional tool of the week: you could use a funnel to make this easier.)
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  3. Put the balloon on the top of the bottle, being careful to have most of the balloon dangling off the side so the baking soda doesn’t fall into the vinegar too early.IMG_20160409_103718366
  4. Once balloon is attached, hold it up. Shake it so the baking soda falls into the vinegar.IMG_20160409_103734142
  5. Sit back and watch the reaction. As bubbles form, pop, and release gas, the balloon will inflate. (The balloon also gets colder.)
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You could try this experiment with other liquids. What happens if you put water in the bottle instead of vinegar? [Nothing.] What if you use lemon juice? What if you add detergent or bubble solution to the vinegar? [You end up with a balloon full of bubbles…]
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There’s a great description of the science of this experiment on the Science Club website: http://www.webinnate.co.uk/science/week2.htm.

Extension: you could see what happens if you “turn this around”: put baking soda in the balloon, use a pipette to squirt vinegar into the balloon, then hold the balloon closed.

Erupting Lemons: Partially core a lemon. Sprinkle some baking soda into it. It will produce a fizzy mini-eruption. If you want more reaction, squeeze the lemon to release more juice, or add more baking soda.

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Invisible Ink: The kids used lemon juice to paint on a piece of printer paper. Then, we left it to dry. When it was dry, we asked them whose painting was whose, and what they were paintings of, as we held up what appeared to be blank papers. Then we ironed them to bring out the message. (The iron needs to be really hot.)

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Opening Circle

We explained that today we would study chemical reactions, and that when we mixed some things together, they would fizz, and when we mixed others, they would change color, and others would go boom!

Song: We sang Boom Chicka Boom. (watch the video here) It’s an easy, and fun, call and response song.

Introduce reactions: We said “Last week we talked about mixtures. There were some things we mixed together and then could separate again (sensory table); other things are solutions, where one substance dissolves into another (like kool-aid), and there’s immisible liquids, like oil and water.”

“This week, we’ll talk about reactions. Sometimes we use reactions when talking about people… like if you tell me a funny joke, I laugh. That’s a reaction. If you said something mean, I would get sad. That’s a reaction. You did something, and it changed me. Sometimes when we mix two chemicals together, they “react”. Mixing them changes the substance in some way. Signs of a reaction are when the substance changes shape or texture, gets hot or cold, makes noise, a smell or light.”

Glow Bracelets / Glow Sticks. [hold up illustration] Explain that inside the bracelet, there’s a chemical mixed with fluorescent dye, and there’s a glass tube that contains another chemical called hydrogen peroxide. When you bend the bracelet, you’ll hear the glass break. It releases the hydrogen peroxide, and the chemicals mix, and the bracelet glows.

Baking soda and vinegar: Mix in plastic cup. Point out that when they’re mixed, they produce foaming bubbles (carbon dioxide gas) and make a fizzy sound.

Alka-seltzer: put a small amount of water and a tablet of alka-seltzer in a zip-lock baggie. Seal it – ask what they see – bubbles. Walk around, holding it up to kid’s ears – what do they hear? Fizz. Ask them to notice what’s happening to the baggie – it swells. Feel the bag – it’s cold. Endothermic reaction.

Exploding paint bombs. Take film canisters. Fill them about halfway with a water-based paint (we used 1 part tempera mixed with 2 parts water). Add half of an alka-seltzer tablet. Seal. Shake a bit. Set down upside down on a piece of paper. Move away! http://kidsactivitiesblog.com/75017/exploding-paint-bombs-activity;  www.housingaforest.com/exploding-art/

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Note: this could make a very big mess. Since we’ve done this in a public park and inside a building, we wanted to contain our mess more, so we were glad to come across this YouTube video www.youtube.com/watch?v=bfNpNTXuWMc which demonstrates how to contain this experiment inside a plastic tub. It’s also lots of fun because the containers go off gradually over a long and unpredictable period of time, and each makes the pop when it launches, then a loud THUNK when it hits the top of the tub! We did this one as a demo, not hands-on for the kids. Method: Put paper down. Line up the prepared paint canisters on the paper, with their lids next to them, and big empty tub nearby. Drop in alka-seltzer, cap, shake, flip. Quickly. Put tub over them. Wait. (Expect about 25 seconds to first pop.)

Zip-lock time bombs: www.geeksraisinggeeks.com/quick-science-experiments/ and https://www.exploratorium.edu/science_explorer/bubblebomb.html.

  • Take one quarter of a paper towel. Put 1.5 tablespoons of baking soda in the middle of it. Fold it into a packet that holds all the baking soda. Set aside.
  • Put ¼ cup of water and ½ cup white distilled vinegar into a Ziploc brand sandwich-size baggie. Seal it most of the way.
  • Now, working very quickly… put baking soda bundle into the baggie. Zip it closed. Toss it into a plastic tub or something else to contain the mess (if desired). Start counting till it explodes. It will take 20 – 30 seconds, unless you shake it first – the more you shake it, the quicker it goes. The fun thing about the Ziplocs is they build anticipation as the kids see the bag swell, and swell more, and more… until it’s bulging and straining, then it starts rocking, then it blows.

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Group management: If you’re doing this in a group of preschool or elementary age children, you need to plan ahead for an effective assembly line. First, have all the kids come up and make a baking soda packet, till you have enough lined up ready to go. Then give each child a Zip-lock. Then add water, then vinegar, then zip closed till you’re ready for them. Then have kids come up 3 or 4 at a time. They hand you the zip-lock of liquid, you open it, put packet in, zip it and toss, and remind them to move back.

Notes from our experimentation: Quantities matter a lot. We tried to find ways to reduce the amount of vinegar to reduce cost / supply use, but you really need this much. Bag choice also matters: we tried using non-Ziploc brand baggies – we discovered that all the bags (or at least the five we tested) all had a minor manufacturing defect which meant they weren’t quite air-tight. Would be fine for bagging a sandwich, but doesn’t work at all with this experiment as the pressure couldn’t build enough to blow. We tried using snack size baggies – just not enough room to work in. We tried using quart size freezer bags. They’re a little too sturdy and you would have to increase your ingredients to use even more. What you wrap the baking soda in matters – Kleenex and fast-food napkins both melt into this nasty shredded pile that leaves a mess that’s hard to clean up – the paper towels stay more intact, so easier to clean up. (Note, we gathered up the bags, poured as much of the liquid down the drain as possible – not on the lawn, and threw away the baggies and paper towels.)

Snack Time Demos

Fizz. We made something that websites in Australia and New Zealand call Sherbet but that isn’t what I think of when I think of sherbet. It’s a fizzy powder not an ice cream substitute. With the kids, I called it fizzy candy powder and compared it to Pop Rocks and Zotz candy. The recipes I found called for citric acid crystals, sugar, baking soda, and drink crystals (koolaid?) to give it a little flavor.

In my grocery store, I found “True Lemon” which is citric acid and lemon oil. We mixed 1/2 teaspoon True Lemon, 2 teaspoons sugar, and 1/4 tsp baking soda.

I reminded the kids of today’s experiment where we cut open lemons and sprinkled baking soda on them – as soon as the baking soda hit the juice it fizzed. I told them the true lemon was lemon juice that was all dried out, and that it needs water to react. So then we sprinkled a little into a cup of water – it fizzed. Then I had kids open their mouths, I sprinkled just a little on their tongues and they closed their mouths and let it fizz. In the morning class, 80% of the kids tried it and the 5 – 6 year old boys wanted to try it again and again. In the afternoon class, I first offered it to some hesitant kids and they refused, so only about 25% of the kids tried it, and one of the young ones was a little distressed by the experience – we had to encourage him to rinse the taste quickly by drinking water and eating more snack. 

Elephant toothpaste. http://preschoolpowolpackets.blogspot.co.uk/2012/01/science-experiment-elephant-toothpaste.html www.stevespanglerscience.com/lab/experiments/elephants-toothpaste/

Although this seems like it would be a huge mess, it’s actually an easy clean up IF you set the bottle inside a cake pan or plastic tub so it contains it all.

  • In one container, mix 1 package of dry yeast and 4 tbsp of warm water (it needs to be between 100 – 110. If it’s colder, it won’t wake the yeast, if it’s hotter, it kills it. We explained this to the kids, describing the yeast as “little tiny bugs” that we’re waking up. They all got the idea. But one tender-hearted child then worried about whether our experiment would be hard on these little bugs…)
  • Then tell a story about an imaginary elephant who needs to brush his teeth, and say you need to make a bunch of pretend toothpaste. (i.e. stall for a few minutes while yeast activates)
  • Put an empty soda or water bottle on a tray (we used a 1 liter Dasani water bottle). Add 1/4 to 1/2 cup hydrogen peroxide. Note: many websites say it has to be the strong type you can get from beauty supplies (it’s called “clear developer“. You’re looking for volume 20 which is 6% hydrogen peroxide), not the weaker 3% concentration you find in the grocery store. But we’ve tried both, and they’ve both worked fine.
  •  To the hydrogen peroxide, add about 10 – 15 drops of food coloring. Then add a couple big squirts of dishwashing detergent. Swirl to mix the contents.
  • Set bottle of peroxide mix into tray. Pour yeast water into bottle. Step back!
  • It oozes and oozes and keeps on oozing.
  • After explosion / extrusion, feel the bottle – it’s warm. Exothermic reaction.
  • We did just one batch of this per class as a demo, not hands-on.

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Outdoor Activities

Hand Warmers – we gave each child a Hand Warmer to shake to activate, explaining that this is a chemical reaction. (here’s the science of how it works)

Film canister rockets: http://imaginationstationtoledo.org/content/2010/08/film-canister-rockets-2/  First, you need film canisters. (It’s best to use the style used for Fuji 35 mm film. where the cap fits down into the canister instead of like a Tupperware lid like the Kodak ones do.) If you don’t happen to have a stack of these almost-obsolete items sitting around, you can easily order them from Amazon or elsewhere.

Prep: Break Alka-Seltzer tablets up into quarters.

In class: Fill the canister halfway with water. Drop in two quarter-tablets. Seal the canister. Flip it upside down so it’s resting on its lid. Back away. As soon as enough pressure builds, the canister will blow off the lid, launching up to 20 feet in the air with a great popping sound! (This MUST be done outside.)

It takes about 15 – 20 seconds on average. If you want the reaction to be quicker, then after you put on the lid, give the container a little shake before you set it down.

Group process: I can do this with about 4 kids at once. First, we set a safety line all the kids needs to stand behind when it’s not their turn. Then I call up 4 kids. I hand them each a film canister and a lid, and tell them “just hold these, one in each hand.” Then I fill each halfway with water, and tell them to keep holding them one in each hand. Then I take a film canister, pop in the tablets, cap, flip, set down – tell that child to get behind the safety line. Then I continue with the next three kids. I do NOT shake the first two canisters, but I do shake the third one a little and the last a lot, so they’ll all go off around the same time.

Math extensions: Measure how far away the canister lands. (Have a long tape measure! Ours landed 10 – 20 feet from where they were launched.) Count how many seconds it takes for one to pop. Try adjusting variables such as using just one quarter tablet and three quarter tablets, or shaking vs. not shaking, to see how many seconds that takes.

Note: If you don’t have alka-seltzer, try it with a tablespoon of vinegar and 1/2 teaspoon of baking soda: http://ecscienceactivities.blogspot.com/2009/02/kindergarten-chemistry_19.html

Mentos and Diet Coke: We ended with this outdoors-only demo. Many of our older kids (5 – 7 year olds) have seen YouTube videos of this. Either very simple demos, or amazingly intricate Mentos fountains. We had 20 ounce bottles of diet coke. I opened one, tried to drop in three Mentos – as soon as the first two hit, it exploded, so number three got blown right out – geyser went up maybe 6 – 12 inches? Fun and messy, but no great thrill, really. Then I used this Geyser Tube, loaded with 6 Mentos. When we pulled the launcher, the geyser only lasted for a few seconds, but it shot many feet up in the air, which the kids loved!

If you want to play more with this experiment, you could also compare how different sodas react: https://www.youtube.com/watch?v=iS2vG1o7Op4

Closing Circle:

Book: In all my searching, I’ve failed to find good books for age 3 – 6 about chemistry. For last week’s mixtures class, I wrote my own book. This week, we just didn’t do a non-fiction reading. For fictional books, there’s a couple options.

11 Experiments That Failed by Offill and Carpenter. This is fun and silly and would be my recommended book to read on a week when you discuss the scientific method. Here is a sample experiment: “Experiments with Perfume. Question: Will seedlings grow if given Eau La La instead of water? Hypothesis: Seedlings will like Eau La La better than water. What you need: pots, dirt, seedlings, water, fancy perfume. What to Do: Place dirt in pots. Plant seedlings in dirt. Water one pot with water. Water other pot with perfume. Watch. What happened: Mom cried. Seedlings died.”

The Secret Science Project That Almost Ate the School by Sierra and Gammell. A silly story about kids preparing for a science fair. Our protagonist has no ideas for projects. She orders a super slime from the internet that eats her cat, her sister, her teacher… and is finally vanquished when the children feed it too many sweets.

Class Structure

Because young children thrive on routine, we try to have the same structure to our class every week, where they explore all our activities hands-on for 20-30 minutes, then we do an opening circle where we explain the science behind what they’ve been experiencing, then they do them all hands-on for another 30-40 minutes then outdoor time and closing circle. But this week, we had several activities that a) would require very close supervision, b) could only be done once or twice so we wanted everyone to see it, and c) could make a really big mess. So, we needed to do things differently, with 20 minutes of hands-on projects, 15 minute circle which included activities, 15 minute snack time which included demos, 15 minutes outside hike, 15 minutes outside activities, then a book to end with. Our morning class handled the new routine fine. The afternoon class didn’t. They lost focus during opening circle, and wandered to snack early, then during snack couldn’t focus on the demos we were doing, so we dropped some. Next year, we’ll think more about how to manage the routine and short attention spans.

Preparation is Key!!!

So much of this class is about messy demos. If you do all the prep in front of kids, they get bored. If you try to prep while kids are in the classroom doing activities, it’s easy to get distracted and miss things. I’ve learned the key to success is to set everything up before class. Each section of class has its own designated plastic tub, out of the kids’ sight. Each tub had its own measuring spoons and cups and everything so NOTHING needed to be moved between tubs. I did things like open and break up all the alka-seltzers in advance so I didn’t have to do it while kids waited. I had a classroom volunteer who I’d told ahead of time that when I finished each experiment, I would hand him a tub and he’d carry it away and handle all the clean-up while I went on to the next one. Here’s my list of tubs and their ingredients.

Note: you’ll need LOTS of ingredients for this class! If you’re just doing one batch of each at home with your kid, you’re probably fine with what’s in your cabinet. But, we had 9 kids in our morning class, and 10 in our afternoon, and we used: 1 gallon of vinegar, 24 ounces of oil, and about 5 pounds of baking soda, plus other ingredients.

More Reactions You Could Try

As always, we had more experiments than we had time for. Here’s some more ideas:

Pop a cork: You could use a test tube with a stopper or a glass bottle with a tight-fitting cork. Fill with either citric acid, baking soda, water or vinegar/baking soda. Test to see what quantity you need to pop the cork. http://childcentralstation.com/2011/08/perfecting-blowing-the-cork.html.

We also considered melting Styrofoam with acetone, and playing with the polymer. But given concerns about acetone toxicity, we decided not to do this. But, in case you’re considering it, I have to tell you that when I tested it, it didn’t work as I expected. When I was a kid, you could take regular nail polish remover, dip a Styrofoam cup in it and it would dissolve away. I bought nail polish remover from the drug store, being sure to get the acetone sort, and it didn’t work – it did have other chemicals mixed in, so maybe modern remover is just not a high enough concentration acetone – others recommended that I get acetone from a chemical supply company instead if I wanted to do this experiment.

Last year, we made Milk from Plastic. Try this at home!

Glitter Volcano: If you have a child who loves pink and sparkly things, then get the prettiest clear bottle you can find. Put in baking soda, then just a little red food coloring, then some pink or silver glitter. Then add vinegar. It’s a pretty and sparkly chemistry experiment. (Source: Geeks Raising Geeks.)

Have fun with all your fizzy explosions!

Make your own bouncing ball or silly putty

img_20161209_191929119_hdrBouncy Ball

The cool thing about this project? It takes a few minutes and a few simple ingredients, and you’ve made a bouncy ball! Downside… it’s not a great bouncy ball. At least I haven’t produced a great one after all my testing.

Here’s my detailed process on this… if you’re just looking for a quick summary of the directions, look at my post on Chemistry Mixtures.

I mostly follow the directions on chemistry.about.com (They credit their source as Meg A. Mole’s Bouncing Ball), plus clues from Science Bob, and Home Science Tools.  I also tested, for comparison, different methods, from Paging Fun Moms and PBS Parents. I’ll comment on those below.

Here’s my current recipe with detailed tips.

    • Borax Solution: Pour 2 tablespoons warm water and 1/2 teaspoon borax powder into a cup. Stir the mixture to dissolve the borax. [The water needs to be very warm, and you need to stir a while to be sure it’s all dissolved.]
    • Pour 1 tablespoon of glue into cup labeled ‘Ball Mixture’. Add food coloring. [I have used Elmer’s all-purpose school glue which yields opaque pastel balls, and Glitter Glue, where the balls turned out a pale shade of the glue color, with subtle hints of glitter, and clear Elmer’s Glue, which is probably the best option – easiest to pour and mix, best results.]
    • Add 1/2 teaspoon of the borax solution you just made and 1 tablespoon of cornstarch to the glue. Do not stir. [Tip: this works best if you use a wide dish where you can spread the glue out a bit – sprinkle the borax solution around over all the glue, then sprinkle the corn starch all over that. If you just dump the solution in one place, you end up with part of the mixture interacting great and turning into a ball and other parts where the reaction never happens, and the ball just won’t form correctly. We learned to use a paper snack tray to mix in as cleaning up a dish after making these takes a LOT of scrubbing – it’s easier to throw away a snack tray.]
    • Allow ingredients to interact on their own for 15 seconds (the video on about.com says 15 minutes, but it’s really seconds), then stir them together to fully mix. Once the mixture becomes impossible to stir, dust your palms with cornstarch, and take your ball out of the cup.
    • Knead the ball by rolling it around in your palms like play-dough. It’s VERY sticky at first. [As you keep rolling it, you’ll feel it start to pull together into a ball. If it’s still really sticky, sprinkle a little more corn starch onto it and keep rolling.]
    • Once it’s solidified, bounce it.
    • When you’re done playing with it, put it in a Baggie – write name on the baggie!

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The ball in the close-up picture was made using this recipe, as was the green one in this picture. The one above used glitter glue. The one below used clear glue.

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You can see from the photos that the balls aren’t perfectly round, and they’re a little cracked looking. They’ve got a decent amount of elasticity to them, and will bounce about 4 – 8 inches up when dropped on a table. If left to sit overnight, they will flatten out on one side… you can kind of re-roll it, but it won’t be quite as round.

I tested a few alternate methods.

So, the method above is: 1) mix borax & water, 2) mix glue and color; 3) layer glue then borax solution, then corn starch

The red ball / blob in the picture above was from the Paging Fun Moms recipe. It was 1) combine water and borax. 2) combine glue, cornstarch, food color. 3) mix those together. This was a complete fail for me, as you can see from the picture. I was not able to spread the water around enough to come into contact with all the glue / cornstarch goo right away, so it bonded some parts, but not others and failed to form a homogeneous ball. (Note: Kids’ Activities Blog recommends a similar method, but half as much cornstarch. I didn’t bother to test it.)

The blue ball was from the PBS parents recipe. It had way more water and cornstarch than any other recipe. Steps: 1) water, borax and cornstarch, 2) glue and food coloring, 3) mix together. Results: a very elastic, bouncy, semi-translucent ball – most satisfying bouncy ball. BUT it left behind about 4 tablespoons of leftover liquid – waste of ingredients. Also, it did not maintain its shape as well as the other recipe, flattening out a lot.

For the yellow ball, I followed the PBS parents recipe, but with the same ingredient proportions as all the other recipes. Made a good ball, it seemed, but it flattened as soon as you set it down. I left the blue ball and yellow ball the same bag overnight, and they mushed completely, blending into each other, and had to be thrown away the next day.

When we follow the recipe I describe in detail above, you get an OK ball. I think it can be a successful class experiment if you set expectations appropriately. If you tell kids they can make the best bouncy ball ever, they’ll be disappointed in their results. If you ask “what would happen if you combined glue, this powder and this liquid? Did you know you can make a ball that bounces??? Isn’t that crazy?” then they might think the results were cool just for the fact that it makes a ball at all.

We will continue to use this activity, even though it’s not perfect, because it IS interesting.

Make your own silly putty.

Sources I used for ideas: http://www.sciencekids.co.nz/experiments/crazyputty.html  http://www.wikihow.com/Make-Silly-Putty http://www.pbs.org/parents/crafts-for-kids/homemade-silly-putty/.

Supplies: Elmer’s Multi-Purpose Glue (apparently Elmer’s school glue does not work); food coloring, liquid starch (Sta-Flo – apparently Niagara doesn’t work); tablespoon, spoon, dish to mix in, plastic eggs.

  1. Put two tablespoons of  glue in a dish.
  2. Add food coloring. Mix.
  3. Add one tablespoon liquid starch. Stir.
  4. Let sit for five minutes.
  5. Knead for five to ten minutes.

Note: The recipes I saw often recommend one part glue and one part liquid starch. That led to a handful of liquidy goo that was not kneadable. I added a bunch more glue to my hand and kneaded that in. So, I recommend you start with two tablespoons. When you first start working with this, it’s goo. It takes several minutes of kneading to turn into silly putty. But, in the end, it was a pretty satisfying imitation of silly putty.

But… we decided not to use this in class. Having to wait five minutes mid-process, then having to knead for 10 – 15 was too much to ask our little kids. Plus, the recipe results in silly putty, and many parents can tell you awful stories of silly putty in their carpet or upholstery, and we decided not to send our families home with a product they’d later resent us for.

Chemistry for Kids: Mixtures

chemistry-mixtures

This week’s class was about a fundamental concept from chemistry: when you mix two things together, sometimes they combine, sometimes they stay separate. (At this age, we don’t get into the details of electrons, molecular bonds, and so on! We just want them to experience it now, and someday when they do get all the details, it will make much more sense to them than kids with limited hands-on experience.)

Question of the Week: Will all things combine when mixed together?

In this blog post, I’ll just tell you what we did. To learn more about the science behind each activity, you can check out the posters I made to hang in class which explains the science behind how each of these experiments work. (Here’s the PDF.)

Activities with Oil and Water:

Free Exploration: Demo this in circle first (see below), then let them explore it on their own. Place out plastic containers (We used plastic Test Tubes, but they were a lot of work to scrub out later, so next year we’ll use clear plastic cups), pitcher of water, jar of oil (vegetable oil or baby oil), water-based food coloring and oil-based food coloring. They can try a variety of combinations. Here’s an article about this:  http://www.metrofamilymagazine.com/May-2012/Simple-Science-Experiment-Oil-Water-and-Food-Coloring/

An option would be to also include detergent, which allows the oil and water to combine.

For the oil coloring, I have used Americolor Oil Food Coloring and Chefmaster Liquid Candy Color. I like the Americolor much better – it mixes better than the thick Chefmaster and is also much easier to clean up. For both, the blue color mixed with both the oil and the water, so I didn’t get quite the color separation I wanted. I was hoping for yellow water and blue oil where you could then shake them together to temporarily make green oily water that would then separate out again. Instead I had green water and blue oil.

img_20161210_134727787Another way to explore oil and water, from The Curious Kid’s Science Book, is to put a thin layer of oil in a dish. Give your child containers of colored water and a pipette. They drip in bits of water and watch them ball up – small pools of water bump against each other and merge into bigger blobs as you watch. Try this in a clear container on a light table, or put a clear container on white paper so the colors are obvious.

Fireworks in a Jar: Fill a jar most of the way with water, then in a separate container, whisk together oil and regular food coloring till the food coloring is broken up into lots of suspended droplets of color. Pour the oil on top of the water – the food coloring will gradually separate out, sink through the oil, and cascade into the water then mix with the water. Do a google search for “fireworks in a jar” to see lots of examples, including I Can Teach My Child.

Lava Lamps: After your child has created lots of containers of oil and colored water, try dropping part of an Alka-Seltzer tablet in one. It sinks to the bottom, reacts to the water, making bubbles that rise up through the oil, carrying up some colored water bubbles, that then sink back down. Do a search for “oil and water lava lamp” to see pictures. We didn’t do this as a class activity, but did demo it in our closing circle.

Making Mixtures

Solutions: You could dissolve salt, or sugar, or honey into water.

Beverage at Snack Time: Make a solution you can drink: use Koolaid or other powdered drink mix you stir into water – talk about how the powder dissolves in the water, and then mixes in. Have them first dump the powder in but don’t stir. Then use a straw to taste the water at the top of the cup and then to taste the kool-aid saturated water at the bottom of the cup. Then stir and taste again. It’s no a homogeneous solution.

Suspension: Mix dirt or flour into a jar of water. Shake it up to make a suspension, then let it settle.

Cooking: Recipes and cooking are all about making mixtures. You could make almost anything! A great snack would be to make either a cake or pancakes to go with the cake recipe song or the pancakes book that we did in circle time.

Make a bouncing ball

Whereas most cooking recipes have some leeway for error (using slightly the wrong amount of an ingredient, or adding ingredients in a different order than written), some chemistry experiments must be done precisely right in order to work. We wanted to have the kids test one of those. (And yes, a few had “failures” when they didn’t follow the recipe, and we showed them how they could succeed by trying again and being precise.) There are more details on this recipe here.

Before starting: make Borax Solution. Mix 2 tablespoons hot water and 1/2 teaspoon borax powder. Stir till all the borax is dissolved.

  1. Pour 1 tablespoon of clear Elmer’s Glue in a paper tray. Add 4 drops food color. Mix.
  2. Sprinkle 1/2 teaspoon of borax solution all over your glue. DON’T STIR!
  3. Sprinkle 1 tablespoon of cornstarch all over the glue / borax solution. DON’T STIR!!
  4. Count to 15 seconds. Then use a stick to stir it together till fully mixed.
  5. Once the mixture becomes impossible to stir, spread a little cornstarch on your palms, pick up the goo.
  6. Knead the ball by rolling it around in your palms like play-dough. It’s a sticky mess at first. Keep rolling till it starts to feel like a ball. (If it’s still really sticky, sprinkle on just a little cornstarch and keep rolling.)
  7. Once it’s solidified, play with it. Bounce it.
  8. Store in a baggie.

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Make bubbles: You could make your own bubbles. There’s fun science in understanding that although water and soap make bubbles, to make long-lasting bubbles, you need some sort of sugar. Here’s one recipe: Measure 3 cups of water into one container. Add 1/2 cup dish soap, and stir GENTLY. Add 1/2 tablespoon glycerin OR 2 tablespoons light corn syrup. Stir gently. You can use it right away, but it works even better the next day.

Separating Mixtures

Chromatography – What color is that black marker? Supplies: strips of paper towel, various brands of watercolor black markers and small container of water. Choose a marker and draw a line 1 – 2 inches from the end of a paper strip. Dip the very end of the strip (below the line) into the water, and lay the rest of it out on the tray. It wicks up the water, bringing the color along with it. With SOME markers, unexpected colors separate out. Learn more: www.crayola.com/crafts/marker-chromatography-craft/ and http://b-inspiredmama.com/marker-chromatography-science-experiment/ www.exploratorium.edu/science_explorer/black_magic.html

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Sharpie tie-dye: Supplies: coffee filters, permanent markers, rubbing alcohol (90%) and pipettes or eye droppers. Kids draw on the coffee filter, then drip on a little rubbing alcohol and watch the colors spread. You can tie-dye shirts or other fabric this way if desired.
www.youtube.com/watch?v=tg8g2mk2fsY

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Sensory Table Sifting: Fill the sensory table with a mixture of items of varying sizes, and strainers that will sift some items out. We had a mixture of rice and beans, and then added glass stones. If they sifted it through the salad spinner bowl, all the rice and beans would fall out, leaving behind the glass stones. If they sifted through the white container, the rice would fall through, but the beans and the stones would remain. You could do lots of other combos – plastic gems in cornmeal, “gold coins” in sand, etc.

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Crystals Painting: You could also do Epsom salt painting this week if you didn’t do it with States of Matter. You make a solution of salt and warm water and paint with it. As it dries, the crystals appear.

Water Table: I soaked water beads the night before (polymers) and put some in the water table with fishing nets (our Tool of the Week) and scoops. I had two brands of water beads – I can’t remember what brand the blue ones are – I’ve used them over and over. The multi-color beads were bio-gels. At the end of the day, the blue ones were whole and ready to be dried and re-used. The multi-coloreds had been squished into lots of little bits of loose jelly we had to fish our of the water. So, test your beads ahead of time!

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Other Activities

Concept exploration – Milk Fireworks: Take a flat shallow dish, pour in a thin layer of whole milk (not skim – you need the fat!). Drop on a few drops of different food colors, near to each other – they mostly float on the surface of the milk, since the water-based colors are less dense than the milk. Dip a q-tip into dishwashing detergent (Dawn and Joy work best), then dip it in the milk near the coloring and hold it there, but do not stir!! Wait a second for the response – the colors fly away from the q-tip. (This photo from Steve Spangler Science shows an effect you may see – you can also do an image search for “milk fireworks” to see lots more, or a video search to see the reaction in action!) Once the reaction slows down, lift the soapy Q-tip and dip it in somewhere else – a new reaction begins. Once the reactions have slowed down, you can gently stir the milk and the colors will swirl around, creating a marbled effect.

fireworks

This is a great experiment! Pretty cheap, easy to clean up, entertaining for all ages. The challenge we found was convincing our three year olds and four year olds to put the q-tip in and hold it there waiting for the reaction. They just want to stir. The colors still move and intermingle, but it’s not as dramatic or pretty.

Art – paper marbling. You can also capture the results of the milk fireworks in beautiful marbled paper. Watercolor paper works best, but paper towels can also be an interesting effect. This does not work as well on a non-absorbent paper like printer paper. BEFORE you do your milk fireworks, cut out squares of paper that will fit well into the container you’ll put the milk in. AFTER you’ve done milk fireworks, take a piece of paper, lay it carefully flat on top of the milk. Press down lightly, just to make sure it’s in contact with the surface of the milk. (Note, children tend to press hard enough to sink it, so be clear in your instructions.) Then lift it off by peeling up from one corner, flipping it over as you do. Set it aside to dry. Some papers will curl up as they dry. If they do, later on you can press them flat under a heavy book. See pictures at Babble Dabble Do and Childcare Network.

Building Toy: ZOOB  are a fun building toy which require learning a new small motor skill for many kids – knowing how to line it up just right and push hard to connect them. They only hook together in certain ways – can form matrices – kind of like molecule models.

Art Activity: Bubble wands. The kids used pipe cleaners and beads to make bubble wands for outside time.  http://www.prekinders.com/bubble-chemistry/

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Large motor: This day is a lot of high concentration, small motor, try not to make too much of a mess activities. The kids need to be able to blow off physical steam. So, we had tumbling mats in the big motor room and had a long outside time to play.

Opening Circle:

Song: We sang the Cake Recipe song. (I explained how when we cook food from a recipe, we’re basically doing chemistry. And that you had to follow the recipe right, because flour, eggs, milk, and sugar can make cake, but it can also make bread, all depending on how you mix it together.)

Before teaching the song, I had them clap the rhythms of the chorus: 1-2-3 1-2-3 mix-mix-mix mix-mix-mix and 1 2 3 4 mix mix mix mix. Rhythm is an important building block for the brain, helping with later math learning and more.

How to communicate the answer to the key “Question of the Week”?  I asked “When you mix things together, do they always combine into one new thing or do they stay separate? Let me show you an experiment, and we’ll see.”

I started with a demo of oil and water. I poured water into a test tube, then showed them the regular Food Coloring, and explained it was color chemicals mixed with water. So, we know it will mix with water. I put a few drops in the water and mixed it.

Then I showed them the oil and explained that water and oil do not like to combine. I reminded them the regular food coloring was made of water, and added a few drops to the oil. It beaded up into little balls. I put the lid on the oil, and showed how I could pour the oil back and forth in the tube, and the ball of food coloring might break up a bit, but would not mix in. Then I poured some oil in with the water, and shook it gently to mix it, then showed how it separated out again, with the oil floating on top of the water. I also added the Oil Food Color to the oil to show how it could mix in because it was color mixed with a chemical that “likes” to connect to oil.

Matter and molecules. We reminded them of last week’s book, I Get Wet, which talked about how water molecules really like to stick together. Then I held up a magnet ball, said “Imagine this is a water molecule (remember, real molecules are so teeny tiny we can’t seem them.) It really likes to stick to other water molecules. So, as soon as it finds one, they stick together (stick two magnet balls together), then then find other water molecules to stick to.”

Set the magnets down and hold up a plastic ball or egg. “We’re pretending this is an oil molecule. It doesn’t like to stick to water.” (show how it doesn’t stick to the magnets.)

Put some magnet balls, then some eggs, then some balls and so on in a clear container so they’re nicely blended. Say “this is oil and water just after we shook them up so they look kind of mixed, just like the oil and water are kind of mixed after we shake them” (show this). “But what happens when we let the oil and water rest? It separates out again, with the oil floating on top.” Shake the balls and eggs – the magnets will grab each other and sink to the bottom, with the “oil” eggs floating on top.

Book: I didn’t find any little kids’ books about chemistry (I did find books for adults and older kids about chemistry experiments to do, but nothing with a story.)

So I wrote a book to meet our needs. It’s called Mixing It Up and talks about mixtures, solutions, suspensions, immiscible liquids, emulsion, and reactions. You can print your own from this PDF. (Note: it’s set up to print on an 11×17 double-sided printer, but will scale down OK to print on 8.5 x 11 paper, and if you have to print single sided, you should be able to assemble it OK.)  In this first draft, I had to use some photos from the internet, not all of which were public domain, so sadly I’m violating copyright with some of the photos… I plan to re-do them all soon.

The way we did circle time, since we had this custom book, was to read the beginning section of the book. Then when we got to the page on immiscible liquids, we set the book down and did the oil and water demo. Then we read the page explaining the molecular idea while also showing the demo with the magnet balls and eggs. We saved the last few pages for closing circle.

Every page of the book shows photos which are experiments parents or teachers can re-create with their kids using simple everyday materials they have at home. We did many of those experiments in this class, but not all.

Closing Circle

Book: You could read Pancakes, Pancakes! by Eric Carle. Not only is this about the chemistry of cooking, but it also goes through how we get flour (harvesting, threshing, grinding – it showed a water wheel powered mill which allowed me to remind them about our Simple Machines unit on Wheels, and showed a water wheel like we use in the water table, but being used to create power before we understood electricity.

You could also read a book about cooking such as Whopper Cake, which would tie in nicely with the song we did… and is terribly silly, so the kids love it.

Book and demos: We read the next to last page of the book I wrote, which talks about emulsifying, and then added a little soap to our test tube of oil and water to show how it helps them to mix, and why this property helps us when we want to wash greasy dishes.

We read the last pages on reactions, then dropped an Alka-Seltzer tablet into another tube of oil and water to show the “lava lamp” effect described above.

Cool ideas we didn’t try:

Like all my posts, this posts includes Amazon Affiliate links. If you click through and purchase something, I get a small payment. However, I do this primarily so you can see what product I am referring to, and can read reviews of it and look for alternatives easily. Most things are available in your local grocery store or drug store.

States of Matter – Chemistry for Kids

states-of-matter

A concept like “states of matter” may seem too abstract to teach to kids 3-7, but there are lots of hands-on ways they can experience the ideas. Once they’ve experienced it, then we just give them the words to describe these things and the concepts to connect the ideas together.

So, first, let’s explore the activities where they experience states of matter. This is a really long post… if you go to the bottom, you’ll find more info about how to teach the concepts that explain these experiences.

If, like us, you’re teaching one two-hour session on this, there are more ideas in this post than you can do in one class. But, if you see the kids for more days, you could spread these ideas over multiple sessions.

Activities to Explore the Change from Solid to Liquid

Ice melting: We filled plastic containers with water and froze them overnight. In class, we put the ice in a tub. Next to it, we put a dish of coarse salt with a spoon, a container of water with eye droppers, and diluted liquid water colors with pipettes. Kids dribbled on substances to melt the ice.

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Challenge: Can you Save Captain America? Prep 24+ hours in advance: Fill a loaf pan halfway with water. Freeze it. Fill it the rest of the way with water. Take a Captain America figure, or any other toy, and drop him in – he’ll settle in the middle of the pan. Freeze it the rest of the way. In class, use it like the ice blocks, but kids have the extra motivation of trying to get the toy out of the ice. This year, we offered one ice block with plastic dinosaurs to excavate, one with pennies, and one with marbles. I did several layers during the freezing process, so the items were suspended at several levels.

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In our afternoon class, we had two girls working very hard at excavating pennies and marbles. They were very focused on choosing a penny, then putting water and salt directly over that penny until they broke through the ice and could remove it. Whenever they broke one free, they’d shout out the news and the class would cheer.

After kids have worked with the ice and the salt for a while, you could take it up to the next level. You could offer wood mallets and kid-friendly chisels. Or you could offer a hair dryer, but take precautions so it won’t land in the water from the melted ice. In our morning class, two boys were very dedicated to melting the entire block of dinosaur ice with a hair dryer.

Cooking Lessons: You could also melt butter or chocolate in a microwave or on a stove.

Activities for Exploring Gasses

Balloons: Trapping Gas in a Container. Pump and Let Go: We had balloons and Balloon Pumps. Kids could fill the balloons, and let go, and the escaping air (gas) propels the balloon, sputtering around the room.

Balloon Rockets: We also set up tracks with balloon rockets: take a toilet paper tube, tape a balloon to it – you need to tape the balloon around the “neck” but you have to tape loosely enough that you’ll then be able to fit the balloon pump into the neck opening. Mount the tube on a string. Then kids use the balloon pump to blow up the balloon. Let go and the balloon flies along the track.

Balloon Spinner: If you mount the balloon on a cardboard ribbon spool instead of a toilet paper roll, then if you inflate and let go, the spool will spin around the ribbon.

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Trapping Gas in Bubbles: Put out bubble solution and wands for free play. As kids play, you can explain that the bubble solution is a liquid which holds together as we fill it with gas (the air from our lungs).

Water table: Have turkey basters and syringes that kids can fill with air (a gas) and put under the water, and use to blow bubbles. (Gas moving through a liquid.)

Helium Balloons: You could have helium balloons and balloons you blow up yourself and kids can compare the differences between them.

Dry Ice: Put a little dry ice and some water inside a plastic bag. Seal it, then watch it expand as the dry ice sublimates into gas. I have also tried dry ice and water inside a baby bottle – it whistles as the gas escapes through the nipple opening – and inside a sippy cup with a straw – it creates a fountain of water. See videos of those experiments here: https://gooddayswithkids.com/2014/09/10/fun-with-dry-ice/.  Note: dry ice should only be used with close adult supervision.

Activities for Exploring Liquids

Surface tension: Put out pennies, pipettes, and water. Challenge the kids to see how many drops of water they can put on a penny. The first 10 or so drops just puddle out to fill the penny, but after that, it starts creating a dome of water. The bigger the dome, the slower you have to work, because each time you add a drop, the whole dome shivers and re-aligns itself. Our record was 30 drops of water! Note, the pipettes required a lot of fine motor skill to manage one drop at a time – our 6 and 7-year-olds could do it. An eye dropper might be easier for younger hands to control.

Volume comparison: You could fill the water table with measuring cups and containers in a wide variety of shapes. If they pour exactly one cup of water into each of these shapes, it can look very different – short and flat, or tall and skinny, etc. You could also have solids (e.g. Duplos or plastic counting bears) and they would see that they can’t necessarily fit the same number of bears into each of the containers, because the bears don’t mold to the shape of the vessel. (Note: our three to four year olds totally miss the science behind this experiment, but they still have plenty of fun scooping up plastic bears and floating them in containers of water.

Comparing States of Matter

3 gloves. Use latex or non-latex gloves from your first aid kit: hours before class fill one with water and freeze it. When setting up for class, fill one with water, and blow one up like a balloon and tie it off. Put the three gloves on a table, with signs explaining the three states. Here’s a PDF of the signs I used.

Sorting Game: Have children sort things into categories of Solid, Liquid, or Gas. There’s several printable sorting games available online. We used one from Have Fun Teaching. There’s also a good one on Teachers Pay Teachers. You could do physical objects instead: any solids, some containers full of liquids, a balloon full of air, and an “empty” container with an airtight lid (a container of air). If you have older kids, put some “tricky” solids… something soft and flowy like silk fabric, and something like sugar or salt that pours and molds to shape, but is really lots of little solids.

Activities for Exploring Evaporation

Art Activity – Epsom salt painting: Dissolve Epsom salts in hot water. Then paint with the water. As the water evaporates, the salt crystals reappear. Use a flashlight and magnifying glass to examine the crystals. (Source: www.ingridscience.ca/node/98)

For the best crystals, use a smooth, tightly textured paper – cardstock works much better than construction paper, where the texture of the paper dominates. Note: the picture on the left is from a previous year’s class, where we got very different results, not the crystalline structures, though still fun. I’m not sure what we did differently…

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You can use a similar technique to make “crystal paintings” by coloring the salt water, and painting on white paper. I’m thinking that would be a great art project for an Anna and Elsa / Frozen themed birthday party…. print a picture of Arendelle, then paint blue ice crystals all over it.

Evaporation experiment: This is a good take-home exercise, or good if you are in the classroom several days a week. Start with a spoonful of salt. Optional: stir in a food coloring or liquid watercolor paint. Then mix in warm water. The salt “disappears” as it dissolves in the water. They will then leave the container of liquid on one of the windowsills. Over the next few days, students can check the container to see if the water evaporated, leaving behind the salt and color.

Grow crystals: If you have time, you could make rock candy or Epsom salt crystals. With these experiments, you dissolve a solid into a liquid, then as the liquid evaporates, the solids gather into crystals. Learn how at the Science of Cooking or Kidz World.

Condensation

Make it Rain: prep a plate full of ice cubes, fill a jar or container a quarter of the way full with very warm water. Set the plate of ice on top. As steam rises off the water, it encounters the ice, and cools and condenses on the jar. (Source.)

Other Activities

Art – Watercolor resist: We used crayons (a solid) to draw. Then painted watercolors (a liquid) on them.

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Art Process – Mixing Colors: Have children use liquid colors (e.g. tempera paint or liquid watercolors) and mix colors in a painting – red and yellow make orange. Then have them use solid colors (crayons, pastels or chalk) and try to mix them. Instead of orange, you end up with red scribbles with yellow scribbles laid over the top of them. The solids do not mix as well.

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Tool of the Week: Thermometers. We always have a tool of the week, and since so much of the states of matter experience is about temperature, we wanted to use thermometers. We filled three containers of water at varying temperatures – ice water, room temperature, and our hottest tap water (120 degrees). We put them in an insulated coffee cup so they would hold temperature as long as possible – the ice water was still filled with ice four hours later!

Kids use their fingers to test the water and to guess what is the warmest and what is the coldest, then measure with a thermometer. This experiment worked better for the older kids with a good grasp of numbers (so they actually understand that 72 is warmer than 48). You could place one slower-to-read thermometer in each cup so they could just look at the numbers and read them out (some kid-friendly thermometers for this experiment are the Learning Advantage Thermometers or ETA hand2mind Thermometers) or you could use an instant-read digital thermometer like this one. My instant-read thermometer from my kitchen wasn’t the best option, as it’s not watertight, and the kids tended to submerge it… it survived somehow.

Outside time: Last year, it happened to be below freezing the day we had this class. (Not typical for Seattle, even in January.) So, we went outside, and found that lots of the sandbox buckets and scoops were filled with ice. We used warm water to loosen it, broke the ice free, then had fun breaking ice into bits.

Clouds: Show pictures of the same location on a clear blue-sky day, on a partly cloudy day and on a rainy day. Discuss how clouds are water vapor. Discuss how they form [evaporation] and what causes the rain to start. You could do water cycle in detail unless you’ll do this in another session of class. If there has been frost recently, you can share with the children that this is when the water vapor in the air (gas) gets so cool that it first turns to liquid (dew), and then freezes into a solid (frost).

More activity ideas (and ways to explain states of matter) at Mommy Lessons 101.

Class Projects

“Not liquid, not solid” aka “Oobleck” aka “non Newtonian fluid”  This involves mixing water and cornstarch. It creates a unique substance. If you pick it up in your hands, you can roll it around quickly and make a solid ball, but when you stop moving your hands, it melts into liquid and dribbles out of your hand. You can stir it slowly like a liquid, but if you smack it with the spoon, it acts like a hard solid. If you make a plastic animal “run” quickly across it, it doesn’t sink in. If you move the animal slowly, it sinks into the “quicksand.” If it moves quickly in a struggle to get out, it stays stuck, but if you pull it out slowly, it breaks free. Learn more at Steve Spangler Science and SciFun.

To make it: I used a 16 ounce container of corn starch – I added water a little at a time (Spangler says the ratio is about 10:1 – 10 parts corn starch, 1 water). Your goal is to create something that feels like a stiff liquid if you stir slowly, but solidifies when you tap on it. On the Ellen Show, they made a giant vat of this stuff that Ellen DeGeneres runs across. See it at www.youtube.com/watch?v=RUMX_b_m3Js.

Other interesting substances you could make:

Flubber. [Should not be eaten! Don’t make this if you have kids likely to eat it.] Mix 3/4 cup warm water, 1 cup white glue or clear Elmer’s glue. In separate container, mix 1/2 cup of warm water and 2 teaspoons of Borax (can find in the laundry aisle at the grocery store. DON’T use boric acid which is a pesticide and very toxic. Just because the name is similar doesn’t mean it’s the same thing!!). Then combine the two mixtures. Knead. Drain excess water. Put in sensory table or tub and let kids play. Store in baggies. If it dries out at all, just rework in some warm water to get back to the right consistency.  (Source: Explore! Ice Worlds which also has a great lesson plan for turning this simple flubber exploration into a full experiment on the movement of glaciers.)

Other recipes for similar substances:

  • Not liquid or solid. 1 cup cornstarch, one cup baking soda. 1/2 cup of water. Mix. it will harden, then soften… will drip from your hands.
  • Gak: 1 cup Elmer’s glue and 1 cup liquid starch. Add starch to glue slowly, mixing it in with a spoon then kneading it as it thickens.

This post explains the science of polymers: http://www.stevespanglerscience.com/lab/experiments/glue-borax-gak/

Snack – Make Your Own Ice Cream  **I have not play-tested this yet.**

Supplies: Small Ziploc bags. (Sandwich size is big enough, but the quart size comes in freezer bag style – the freezer bags are sturdier). Optional tape. Gallon size Ziploc bags. Half-and-half, vanilla, sugar, salt or rock salt, ice cubes or crushed ice, spoons, gloves or washcloths. (Quantity depends on how many kids will be making ice cream – the directions below are for one child’s serving.)  Recipe and directions written in kid-friendly language to be placed on table. (laminating these will help them survive better)

  1. In small Ziploc bag, mix the following (Older kids can measure their own ingredients, younger children will need help.)
  • 1/2 cup of half and half
  • 1/2 teaspoon vanilla
  • 1 – 2 tablespoons sugar

2. Seal small bag – it’s important to squeeze all the extra air out! Tape the bag closed OR place inside a quart size Ziploc.
3. In a gallon size Ziploc, put several ice cubes or scoops of crushed ice and about 3 tablespoons of salt or rock salt*. It should be filled about halfway.
4. Put small bag inside big bag, nestled down into the ice.
5. Seal the big bag – it’s important to squeeze all the extra air out!
6. Give kids gloves or a washcloth to wrap bag in. Then have them shake and/or rub the bag for five or more minutes till the milk mixture is slushy. (liquid turns to solid!)
7. Remove little bag from big one. Wipe the salt off the top of the little bag before opening.
8. Give kids a spoon and let them eat ice cream out of the bag.

Explain to the older kids why we use the salt: The salt lowers the freezing point of water from 32 degrees to 20 degrees or less. This very-cold ice makes an environment where the ice cream can freeze.

To learn more about the science of this snack, see “Ice Cream in a Bag Lesson Plan.”

Another method for ice cream is: Mix 1 cup of whipping cream, 1 cup of half and half, 1 tsp vanilla and ¼ – ½ cup sugar. Put in a small container with an airtight lid. (If it’s not watertight, seal with tape.) Put it inside a bigger round container (like a coffee can.) Fill the large container with layers of ice and rock salt. Roll the can back and forth between students (or up and down a slide) for about 15 minutes till ice cream hardens. Then eat it!

Another snack option is a root beer float, which also demos the states of matter.

Science Demos: We had a couple experiments to do that required very close adult supervision to avoid steam burns, so we did those as demonstrations during snack time when all the kids were seated. If you’re working with just one or two kids, they could easily participate with appropriate caution.

Changing states with heat: have a hot plate, small pot (clear glass would be great), and ice. Show the children the ice, explain that it is water in solid form. Put it in the pot – ask what will happen as you heat it. Show how as it heats, it turns to liquid. Continue to heat. As the steam starts to rise and they can see it, ask them what the steam is – it’s water in gas form (although to be really technical, gas is invisible… what we’re seeing that we call steam is actually tiny suspended drops of water) Ask what would happen if we turn off the heat and let it cool down. Ask what would happen if we put the pot in the freezer.

Teach vocabulary as you do the demo: melting, boiling, evaporation, freezing. If you have readers in your group who love big words, you could print a poster of this graphic, from www.ck12.org  (This site also has a good description of key concepts of states of matter.)

states

We used a closed electric kettle for this demo, which releases steam in a concentrated location, which allowed us to demonstrate condensation as well:

Condensation – gather gas and observe as it changes to liquid: As the water boils, ask the child to watch for steam (gas). As soon as they see it, hold a clear plastic cup upside down over the spout. (With close supervision!) When the kettle switches off, count to five, then turn the cup over and look inside. What do you see? (Liquid water.) Explain that as the steam cools, it turns back to water.

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The microwave demo: Take a quart size freezer bag, Ziploc style. Ask a child to put in a few ice cubes – solid water – seal it well. Ask them what happens when you put things in the microwave – they get hot. Put it in the microwave for one minute. What’s happened to the ice – probably partially melted, part still ice. Have them touch the outside of the bag to see what temperature it is. Still cold. Put it in for another minute or so. Now it’s all liquid – touch the bag (VERY carefully at first to test temperature!!) – now it’s hot. Tell the kids that’s the last time they’re allowed to touch the bag. Heat it then in 20 second intervals – you’ll see the bag inflating like a balloon. Explain that is the liquid water turning into gas and expanding. You can take it out of the microwave when it’s expanded (carefully!!) and show how quickly it deflates as it cools. Do NOT open the baggie of steam, and DON’T let them touch it. If you run the microwave long enough, and there’s enough steam, it will pop the bag open. I don’t really recommend this, but it happened to us, and didn’t make too much of a mess…

Communicating the Big Idea – in Opening Circle

Three states of water, hands-on:

  • Solid: Pass around a cup with an ice cube in it. Ask them if they know what ice is made of (water). Have them touch the ice. Ask them to describe the ice – it’s cold, it’s hard. Ask if it changes shape if they pour it out of the container into their hand. Show how that it doesn’t change shape. Pick up a few other objects from around the room. Show how you can pick them up and set them down and they stay the same shape. Ask the kids for examples of other solids.
  • Liquid: Then pass around a cup of water. Ask them to describe it – cool, wet, liquid. Pour some from the cup onto a flat dish. Did it change shape? Then pour it into a test tube or other tall skinny container. Did it change shape? Demo a few other liquids: maybe vegetable oil and honey or molasses. You could either leave them in a closed bottle and just show how they move differently, or, you could squeeze out a little and let the kids touch it so they could see how different each of the liquids is. Ask for other examples of liquids.
  • Use a plastic syringe (or pipette) to pull up some water and show them how the syringe has water in it. Then squirt the water back into a container.
  • Gas: Ask if there’s any gas in the room. Tell them the room is full of air, which is a gas. Hold up a plastic syringe and draw it open, filling the cylinder with air. Say “this container is full of something. What’s it full of? (Air) Can you see it?” Push the air out – ask if they saw it come out. Then pull in more air and hold it close to a child’s hand, and blow the air out on their hand – did they feel it? Then fill the syringe with air, hold it under the water, push out the air and ask them what they see – bubbles of air moving through the water. Ask if we can trap a gas, and then blow up a balloon or show them a helium balloon so they can see how the gas is trapped in an airtight container.

Book: We read I Get Wet by Vicki Cobb (my new favorite author of science for young children!). It does a nice job of exploring the liquid water and explaining why it makes us wet. We demoed the ideas from it as we went along, pouring water into different shape containers, using a pipette to show how a drop of water forms into a ball and drops, putting water on waxed paper and on a paper towel.

Song: We used the Matter Song from Teachers Pay Teachers, but I made some changes to the lyrics in the liquids verse, and we also changed the order to solids, then liquids, then gas. Other options at: https://www.youtube.com/watch?v=Bn3v_LUVIOI or https://www.youtube.com/watch?v=fhhFwdJqvfw

Closing Circle Time

Note: I made up a set of posters which teach the vocabulary of melting, boiling, condensing, and freezing. They’re in this states-of-matter-vocabulary PDF. There’s a different set of worksheets on this at: http://fivejs.com/changes-states-matter-free-printable-worksheets-solid-liquid-gas-plasma/. I used a little of their illustration in making my posters.

Book: We used What Is the World Made Of? by Zoehfeld. However, it’s too wordy, so I wrote a much shorter version of the words, printed it and taped it to the back of the book so I could read that version as I flip through the pages. Talks about solids, liquids and gas and has some silly ideas: “have you ever seen anyone walk through a wall?” or “have you used milk for socks?”

Matter and Duplo molecules: Talk about matter and how everything that they can see, hear, touch, smell, or taste is made of matter. Explain that matter comes in three forms: solid, liquid, gas. (We’re not going to get into plasma with this age group.) Explain that matter is composed of molecules – very tiny pieces.

We reminded them that a few weeks ago, when discussing electricity, we talked about atoms. We explained that molecules were made up of clusters of atoms, but they were still so tiny we can’t see them. We showed them a Duplo and said we would use this as a “model” and pretend it was a molecule of water.

Demo-ing States of Matter with Duplos and a kettle

molecules

Solids: Show a container holding 10 – 15 Duplos, all stuck together. Say these water molecules are all packed tightly together right now – they’re a solid – so we’re pretending that this is water in a solid state – ice. Shake it around in the container a little – see how the solid retains its shape? Pick up a few other solids at random – a book, a marker – whatever you have handy – have the kids notice how you can pick up and move solids and they hold their shape.

Show the kids one ice cube. Explain that it’s water in solid form. Put it in an electric kettle (you can cheat and have a little water already in the kettle to make the next step of the demo easier.) Ask what will happen when you heat it.

Melting: As you heat the ice a bit, go back to the Duplo demo. Let’s pretend to heat up our solid molecules. The heat adds energy. The molecules get excited. They loosen their bonds and drift farther apart. (Break up the Duplos and spread them across the bottom of the container.) “See how they flow across the bottom of the tray, taking the shape of the container like a liquid?” Pour them into a different shape of container like you used with the containers of water when you read I get wet. Remind them of the other liquids you looked at. Then pour a little water from the kettle – “look, the ice has melted. It’s turned from solid to liquid. What happens if we heat it more?

Boiling / Evaporating

As you heat the water in the kettle more, go back to the Duplos. As we heat it, the molecules get really excited – they start bouncing around. (Shake the container to make them jump.) When they get really excited, they turn into gas that dissipates around the room. (Shake them so hard they fly out of the container – the kids love this!)

Go back to the kettle – point out the steam that’s coming out of the top. “Look, it’s boiling. Liquid water is turning into water vapor – a gas.”

Condensation

Use a plastic cup to capture some steam. Tip it up, count to 5 and show them what’s inside. Some liquid water will have condensed from the steam.

Take your container of loose Duplos and put a lid on it (or seal the bag if you’re using a plastic bag.) You’ve captured some gas. Shake it fast to show how the molecules can’t escape. Then shake it slower, say it’s cooling down, shake it slower, letting all the molecules settle to the bottom of the container – it’s liquid again.

Freezing

Ask what would happen if we put our cup of liquid water in the freezer. It would freeze to solid. Build the Duplos back into a solid mass.

Solid, Liquid, Gas game: If we called out “solid”, they grab hands with all the other kids, squeeze in tight, lock their elbows and freeze in place. If we try to move them, they all stay in the same shape as we shove them around the room. If we call “liquid”, they still held hands, but loosen apart from each other, moving and flowing around the room. If we push them, they flow out of our way. If we say “gas”, they let go and move away from each other to fill the space, moving around the room. This could a movement game, or it could also be done to music as a “states of matter dance party.”

Use the vocabulary as you play: “it’s getting colder, you’re freezing, get close to all the other molecules and hold on for a tight bond.” “It’s warming up, you’re melting, loosen up your bonds, and flow.” “It’s really hot, you’re boiling, let go of your bonds and dissipate around the room.”

Will they understand?

Our three to four year olds should get at least some grasp of the three states of water. Over the next few days, try quizzing them about whether something is solid, liquid or gas, and they’ll get it right more times than wrong.

You may notice the kids playing with the ideas for the next few days. They may mix the ideas around in their brains. When they do, it’s easy to reinforce what they’ve got right, and add corrections as needed to  solidify their knowledge. (Read about my process of teaching my then 3-year-old about states of matter. At first, I thought he didn’t get it, but then observed how he processed the ideas over the next few days.)

This kinesthetic game really reinforced the learning for the kids. Last year, three days after the class, I listened to my then-5-year-old describe states of matter to his preschool teacher. As he described each, he was moving his body just like we did in this game. As a 6 year old, he can repeat back to me what we taught about molecules.

Optional Preview/Review: You may send a link to a video to parents before class that they can preview with their child to set up the week’s activity, or it could be sent as a follow-up. Here are some options, from the one I like best to least:

More Books

We read our favorite books in circle, so see info on those above. Here are other options:

Matter: See It, Touch It, Taste It, Smell It by Stille. This is a preschool – first grade appropriate book that describes the basics about states of matter. We only read about half the pages in circle. Each page included “fun facts” for older readers, which we skipped in circle. Sample content: “Can you pour it? Does it spill? It must be a liquid…. You cannot hold a liquid. A liquid runs through your fingers.” (Small quibble – one of their examples of a solid is a glass window. There is some debate whether glass is a solid or a liquid.)

Change It!: Solids Liquids Gases and You by Mason. Age 4 – 7. Each state is introduced with a brief description, everyday examples, and a challenge – “can you find three more solid objects in this picture?” There is also a simple activity for each state. (Making play-dough for solids, putting water in different shaped containers for liquids, etc.) Good.

What Is a Solid? by Boothroyd.(Also has a Liquid and a Gas book.) This would be a fine series to read with ages 3-5. Simple words, familiar examples, pictures are fine.

What Is a Solid? by Peppas. (Also has a Liquid and a Gas book.) For first grade and up. Good descriptions, engaging photos, “what do you think?” sidebars on every page that encourage kids to make their own observations and try their own experiments. Good, just too advanced for many of our students.

Splat!: Wile E. Coyote Experiments with States of Matter by Slade. This is aimed at 3rd-5th graders, but my five-year-old loves it because of the Wile E. Coyote theme. I certainly wouldn’t use it in a group of 3 to 6-year-olds, but it works one on one if the young child is interested in it and you can stop to explain and give more details.

What Are Solids, Liquids, and Gases? by Spilsbury. 4th grade and up.
Solids, Liquids, and Gases by Stille. 4th grade and up.
States of Matter by Mullins.
Way over the head of our students. Of the three, I like Spilsbury best. But, even though you wouldn’t read these to young kids, they might still be useful to YOU. General hint for those of you are feeling uncertain of your grasp of science concepts: if you’ll be teaching preschool age kids, it may be really helpful to you to read a 4th grade level book to yourself in advance. It explains the concepts at a slightly higher level than what you’ll be covering in class, which means if kids have questions, it can help you to answer them.

Experiments with States of Matter, by Cook. Has good directions for some classic kids’ science experiments, many of which have any direct relation to states of matter: baking soda and vinegar volcano, chromatography, invisible ink, etc.

Material World the Science of Matter by Jay Hawkins (non-fiction, has some nice descriptions of activities, nice photos, the activities are mostly too complex for our class, some of the info is a bit advanced)

Chemistry – Dramatic Reactions

[An updated version of this post is at: https://inventorsoftomorrow.com/2016/12/22/chemical-reactions-for-kids/, but it does not include all the experiments in this post, so read them both. 🙂 )

During our Chemistry unit, we did States of Matter, then Mixtures, then Reactions, and now Dramatic Reactions. At the beginning of the year, I’d written a flyer for our Family Inventors’ Lab, which said amongst the activities it listed, that we would “make things go boom.” And this was the week to fulfill that promise!

We began with 20 minutes of gathering time, where we had just some simple activities inside: invisible ink with lemon juice and melted crayon drawings, Magna-Tiles and Slot-Together Translucent Builders (aka Crystal Climbers.)

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We also made rockets with card stock. (Click here for a printable rocket template you can cut out and assemble. PDF also includes a pattern for making a rocket with craft foam)

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You shape these rockets around a film canister, but then you can take the film canister out. You CAN use these rockets for the film canister rocket launch I describe below. I don’t recommend it, because a) it makes it harder to fill and seal the canister for the launch, b) with the paper rocket, the canister will only launch about 6 – 12 inches into the air instead of 6 – 12 feet, and c) using it this way pretty much ruins your lovely little paper rocket – they end up wet and crumpled.  (You could fix issues c by making rockets out of craft foam, and they could be infinitely re-useable.)

Opening Circle

We sang “boom chicka boom“, an easy and fun call and response, that tied into our theme of making things go boom.

We reminded them of two weeks ago when we mixed materials together, and some mixed and some stayed separate we reminded them that last week we talked about reactions – how when you mix two things together, they react (make noise, fizz, change temperature, etc.) and that it changes them. We told them that this week we’re going to go outside, and use chemical reactions to “make things go boom.”

Demos and Experiments Outdoors

Film canister rockets: http://imaginationstationtoledo.org/content/2010/08/film-canister-rockets-2/  First, you need film canisters. (It’s best to use the style used for Fuji 35 mm film. where the cap fits down into the canister instead of like a Tupperware lid like the Kodak ones do.) If you don’t happen to have a stack of these almost-obsolete items sitting around, you can easily order them from Amazon or elsewhere. Break Alka-Seltzer tablets up into quarters. Fill the canister halfway with water. Drop in two quarter-tablets. Seal the canister. Flip it upside down so it’s resting on its lid. Back away. As soon as enough pressure builds, the canister will blow off the lid, launching up to 20 feet in the air with a great popping sound! (This MUST be done outside.)

It takes about 15 – 20 seconds on average. If you want the reaction to be quicker, then after you put on the lid, give the container a little shake before you set it down. We had adults actively leading this – see my notes on group process later in the post.

Math extensions: Measure how far away the canister lands. (Have a long tape measure! Ours landed 10 – 15 feet from where they were launched.) Count how many seconds it takes for one to pop. Try adjusting variables such as using just one quarter tablet and three quarter tablets to see how many seconds that takes.

Note: If you don’t have alka-seltzer, try it with a tablespoon of vinegar and 1/2 teaspoon of baking soda: http://ecscienceactivities.blogspot.com/2009/02/kindergarten-chemistry_19.html

Exploding paint bombs. Take a film canister. Put in a water-based paint (we used tempera mixed half and half with water). Add an alka-seltzer tablet. Seal. Shake a bit. Set down upside down on a piece of paper. Move away! http://kidsactivitiesblog.com/75017/exploding-paint-bombs-activity;  www.housingaforest.com/exploding-art/

Note: this could make a very big mess. Since we meet in a public park, we wanted to contain our mess more, so we were so glad to come across this YouTube video www.youtube.com/watch?v=bfNpNTXuWMc which demonstrates how to contain this experiment inside a plastic tub (so it can even be done indoors.). It’s also lots of fun because the containers go off gradually over a long and unpredictable period of time, and each makes the pop when it launches, then a loud THUNK when it hits the top of the tub! We did this one as a demo, not hands-on for the kids.

Ziploc time bombs: www.geeksraisinggeeks.com/quick-science-experiments/ and https://www.exploratorium.edu/science_explorer/bubblebomb.html.

  • Take one quarter of a paper towel. Put 1.5 tablespoons of baking soda in the middle of it. Fold it into a packet that holds all the baking soda. Set aside.
  • Put ¼ cup of water and ½ cup white distilled vinegar into a Ziploc brand sandwich-size baggie. Seal it most of the way.
  • Now, working very quickly… put baking soda bundle into the baggie. Zip it closed. Toss it aside. Start counting till it explodes. It will take 20 – 30 seconds, unless you shake it first – the more you shake it, the quicker it goes. When you do the film canister rockets, it can be hard to tell exactly when they’ll pop. The fun thing about the Ziplocs is they build anticipation as the kids see the bag swell, and swell more, until it’s bulging and straining, then it starts rocking, then it blows.

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We did have all the kids make their own time bombs. with lots of adult support. See notes below on group process.

Notes from our experimentation: Quantities matter a lot. We tried to find ways to reduce the amount of vinegar to reduce cost / supply use, but you really need this much. Bag choice matters: we tried using non-Ziploc brand baggies – we discovered that all the bags (or at least the five we tested) all had a minor manufacturing defect which meant they weren’t quite air-tight. Would be fine for bagging a sandwich, but doesn’t work at all with this experiment as the pressure couldn’t build enough to blow. We tried using snack size baggies – just not enough room to work in. We tried using quart size freezer bags. They’re a little too sturdy and you would have to increase your ingredients to use even more. What you wrap the baking soda in matters – Kleenex and fast-food napkins both melt into this nasty shredded pile that leaves a mess that’s hard to clean up – the paper towels stay more intact, so easier to clean up. (Note, we gathered up the bags, poured as much of the liquid down the drain as possible – not on the lawn, and threw away the baggies and paper towels. You could do this inside – I’d toss the bags onto a oil drip pan or into a sensory bin to contain the liquid that blows out of them.)

Tool of the week option: use a thermometer to check water temperature.

Elephant toothpaste. http://preschoolpowolpackets.blogspot.co.uk/2012/01/science-experiment-elephant-toothpaste.html www.stevespanglerscience.com/lab/experiments/elephants-toothpaste/

Although this seems like it would be a huge mess, it’s actually an easy clean up IF you set the bottle inside a cake pan or plastic tub so it contains it all.

  • In one container, mix 1 package of dry yeast and 4 tbsp of warm water (it needs to be between 100 – 110. If it’s colder, it won’t wake the yeast, if it’s hotter, it kills it. We explained this to the kids, describing the yeast as “little tiny bugs” that we’re waking up. They all got the idea. But one tender-hearted child then worried about whether our experiment would be hard on these little bugs…)
  • Then tell a story about an imaginary elephant who needs to brush his teeth, and say you need to make a bunch of pretend toothpaste. (i.e. stall for a few minutes while yeast activates)
  • Put an empty soda or water bottle on a tray (we used a 1 liter Dasani water bottle). Add 1/4 to 1/2 cup hydrogen peroxide (note: it’s gotta be the strong type you can get from beauty supplies, not the weaker 3% concentration you find in the grocery store. In a beauty supply store, it’s called “clear developer“. You’re looking for volume 20 which is 6% hydrogen peroxide.)
  •  To the hydrogen peroxide, add about 10 – 15 drops of food coloring. Then add a couple big squirts of dishwashing detergent. Swirl to mix the contents.
  • Set bottle of peroxide mix into tray. Pour yeast water into bottle. Step back!
  • It oozes and oozes and keeps on oozing.
  • After explosion / extrusion, feel the bottle – it’s warm. Exothermic reaction.
  • We did just one batch of this per class as a demo, not hands-on.

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Mentos and Diet Coke: We ended with this outdoors-only demo. Many of our older kids (5 – 7 year olds) have see YouTube videos of this. Either very simple demos, or amazingly intricate Mentos fountains. We had 20 ounce bottles of diet coke. I opened one, tried to drop in three Mentos – as soon as the first two hit, it exploded, so number three got blown right out – geyser went up maybe 12 inches? Then I used this Geyser Tube, loaded with 6 Mentos. When we pulled the launcher, the geyser only lasted for a few seconds, but it shot many feet up in the air. If you want to play more with this experiment, you could also compare how different sodas react: https://www.youtube.com/watch?v=iS2vG1o7Op4

Pop a cork: As always, we had more experiments than we had time for. You could use a test tube with a stopper or a glass bottle with a tight-fitting cork. Fill with either citric acid, baking soda, water or vinegar/baking soda. Test to see what quantity you need to pop the cork. http://childcentralstation.com/2011/08/perfecting-blowing-the-cork.html.

We also considered melting Styrofoam with acetone, and playing with the polymer. But given concerns about acetone toxicity, we decided not to do this. But, in case you’re considering it, I have to tell you that when I tested it, it didn’t work as I expected. When I was a kid, you could take regular nail polish remover, dip a Styrofoam cup in it and it would dissolve away. I bought nail polish remover from the drug store, being sure to get the acetone sort, and it didn’t work – it did have other chemicals mixed in, so maybe modern remover is just not a high enough concentration acetone – others recommended that I get acetone from a chemical supply company instead if I wanted to do this experiment.

Snack and Circle Time

After our experiments, we came inside for snack. While they ate, I read the book 11 Experiments That Failed by Offill and Carpenter. This is fun and silly and would be my recommended book to read on a week when you discuss the scientific method. Here is a sample experiment: “Experiments with Perfume. Question: Will seedlings grow if given Eau La La instead of water? Hypothesis: Seedlings will like Eau La La better than water. What you need: pots, dirt, seedlings, water, fancy perfume. What to Do: Place dirt in pots. Plant seedlings in dirt. Water one pot with water. Water other pot with perfume. Watch. What happened: Mom cried. Seedlings died.”

Fizz. Then we made something that website in Australia and New Zealand call Sherbet but that isn’t what I think of when I think of sherbet. It’s a fizzy powder not an ice cream substitute. With the kids, I called it fizzy candy powder and compared it to Pop Rocks and Zotz. The recipes I found were for citric acid crystals, sugar, baking soda, and drink crystals (koolaid?) to give it a little flavor.

In my grocery store, I found “True Lemon” which is citric acid and lemon oil. We mixed 1/2 teaspoon True Lemon, 2 teaspoons sugar, and 1/4 tsp baking soda.

I reminded the kids of last week’s experiment where we cut open lemons and sprinkled baking soda on them – as soon as the baking soda hit the juice it fizzed. I told them the true lemon was lemon juice that was all dried out, and that it needs water to react. So then we sprinkled a little into a cup of water – it fizzed. Then I had kids open their mouths, I sprinkled just a little on their tongues and they closed their mouths and let it fizz. In the morning class, 80% of the kids tried it and the 5 – 6 year old boys wanted to try it again and again. In the afternoon class, I first offered it to some hesitant kids and they refused, so only about 25% of the kids tried it, and one of the young ones was a little distressed by the experience – we had to encourage him to rinse the taste quickly by drinking water and eating more snack. 

Class Structure

Because young children thrive on routine, we try to have the same structure to our class every week, where they explore all our activities hands-on for 20-30 minutes, then we do an opening circle where we explain the science behind what they’ve been experiencing, then they do them all hands-on for another 30-40 minutes then outdoor time and closing circle. But this week, we had several activities that a) would require very close supervision, b) could only be done once or twice so we wanted everyone to see it, and c) could make a really big mess. So, we needed to do things differently, with 20 minutes of hands-on projects, 5 minute circle, 60-70 minutes of outdoor demos and hands-on alternating, 10 minutes of circle and snack and a very quick outdoor hike.

Group Process

If you’re working with just a couple kids, you can ignore this section – but if you’re working with a group, be sure to think about process!!

In the morning session, we were differing from our normal routine and we failed to think through the kid-management process in detail. And even though only 5 kids were there that day, it was pretty chaotic. When I was trying to do a demo, they’d all be swarming up around me. When they were doing hands-on experiments, they weren’t listening well and were trying to jump ahead in ways that would make the experiment fail. And when I was cleaning up one experiment and prepping the other, they were running around in circles. It was crazy!

So, for afternoon class, we made a plan and had a whole different approach. And with 11 kids, it was MUCH calmer than our 5 kid morning!

Prep: I’d done most of this for morning, but refined it more for afternoon. Here’s what I ended with… For each experiment, I had all the materials I would need for it in its own designated plastic tub, out of the kids’ sight. Each tub had its own measuring spoons and cups and everything so NOTHING needed to be moved between tubs. I did things like open and break up all the alka-seltzers in advance so I didn’t have to do it while kids waited. I had a classroom volunteer who I’d told ahead of time that when I finished each experiment, I would hand him a tub and he’d carry it away and handle all the clean-up while I went on to the next one. My co-teacher was my designated assistant during experiments, and during transitions between experiments, she would lead the kids in a sitting-in-your-chairs Simon Says game, which helped to keep them focused on listening!

Opening Circle. In the morning group, I was in a hurry and tried to do opening circle at an activity table and without doing a gathering song, and I just couldn’t get their attention focused on anything I was saying! In the afternoon, we gathered in our regular circle area. We did a call and response song, and it made all the difference in getting all the kids’ attention focused on the same thing!

During opening circle, I explained that outside we would be doing some demos and some hands-on, but that some were messy and some were dangerous, and all would only work if they could do a good job of listening and paying attention. I had each carry a chair outside, and put all the chairs in a line and each sat down. Then we took some PVC pipe and made a safety line halfway between them and my work area, telling them not to cross that without permission.

I would do a demo while all were sitting, then call up a group of four or five kids up to the line to do the experiment while the others sat in their chairs and watched. My 5 – 7 year olds came up to the line on their own. For the 3 and 4 year olds, I asked the parents to help them one-on-one.

For film canister rockets, we assembly lined: I would go down the line, hand each kid a canister and a lid. My co-teacher would go by with the pitcher of water and fill each halfway. Then we’d work together. While the child held the canister, I’d drop in the tablet, cap it, and hand it to my co-teacher. She’d flip and set down. She’d be careful not to shake the first couple, then shake a little and the last one got a bigger shake, so they’d all blow at about the same time. Then we’d have to find all the film canisters, which can travel quite a way! Then we’d bring up the next line. Every child got to do the experiment twice.

For Ziploc time bombs, we had four kids on the line, and I took one up to make a baking soda packet then sent them back behind the line, then the next made a baking soda packet, and so on. Then I called up child A and gave them a bag to hold. I added the water, my co-teacher added the vinegar. The child went back to the line, holding the bag. Once everyone had a bag, I went down the line, doing a quick: drop the baking soda bundle into the bag. Seal tightly. Toss to the ground behind me. And then watch them all explode! Every child did the experiment once.

All in all, it was a fun ending to our chemistry unit!

I wish I had more pictures, but our hands were busy! Many of the posts I link to above have photos and videos of the experiments in progress.

Chemistry – a Sequence of Experiments

In our class, we did four weekly sessions on chemistry: States of Matter, Mixtures & Solutions; Reactions; More Reactions.

Another way to approach chemistry would be as a sequence of experiments, either done all in a row in a single session, or one experiment per day for several days running, or whatever. These start with a basic concept, then build on it.

Oil and Water (Immiscible Substances)

  • Concept 1: Water will combine with water. Oil will combine with oil.
    • Take two containers. Put water in each. Then pour the two containers together. They mix – water likes water. (To make this more interesting: Color one container yellow with food coloring or liquid watercolors. Color the other blue. Then mix them together – they immediately intermingle, and make green.)
    • Take two containers. Put vegetable oil in each. Use a food coloring that will combine with oil, such as Americolor Candy Oil. Color one container one color, and the other a different color. Mix the two container together – they immediately intermingle.
  • Concept 2: Oil and water don’t combine. Pour water in a jar or clear container. Gently pour in some oil.  (Can re-use water and oil from experiment above.) Do they mix? No. Explain why. (For a 3 or 4 year old, you just say some substances don’t like each other, and won’t mix together. For older children, you can get into more of the scientific detail about positively and negatively charged molecules)
    • You can point out that the oil always floats to the top, because it’s “lighter weight” or less dense. (Again, the older the child you’re working with, the more sophisticated your description of density can be.)
    • Put a lid on the container, and gently pour it back and forth, making “waves.”
    • Shake the container really hard – can you mix the oil and water? At first, it might look like you have…
    • Then set the container down and watch what happens. The small bubbles of water find each other, and grab hold of each other and sink toward the bottom. The small bubbles of oil grab each other and float to the top. Pretty soon, you have your two layers back again.
  • Concept 3: Oil and water-based things don’t mix
    • In one container, pour a small amount of oil. Then drip in either food coloring or liquid watercolor. Explain that these are colors mixed with water. Will they mix with the oil? No. Take a fork or whisk and beat them together (or seal the container, and shake it lots.) Did they mix? Nope – just made lots of little bubbles of colored water in the oil. Kids can use toothpicks to push the little bubbles together – they grab hold of each other and make bigger bubbles in the oil
  • Experiment 4: “Fireworks in a Jar”
    • Put some water in a see-through container. In another container, mix together oil and water-based coloring (you can re-use your mixture from concept 3 experiment. Then gently pour the oil on top of the water. The food color bubbles gradually sink through the oil. When they hit the water, the color will disperse through the water. To see pictures of this in action, just search for “fireworks in a jar.”
  • Experiment 5: “Lava Lamps”
    • You can use your “fireworks in a jar” mixture for this (or make a new container of colored water and oil.) Then add an Alka-Seltzer tablet (or some table salt). It will create bubbles, which carry the colored water up through the oil, then it pops and they sink back down, etc. To see pictures of this experiment, just search for “lava lamps kid science”.
  • Experiment 6: At some point, you’ll be cleaning up. If your child got oil on their hands, you can have them wash their hands with just cold water. When they’re done washing, show them that their hands are still oily. Now wash again with soap. Now the oil is gone. Why? The soap helps the oil and water combine, and the water rinses away the oil. (Science of this described here.)
  • Experiment 7: Take a container with oil and water in it. Shake it to show they won’t mix. Now add some liquid hand soap or detergent. Shake it. They’ve combined. (Learn about the science here.)  Soap is an emulsifier. It helps oil and water stay combined.
  • Experiment 8: Vinegar and oil don’t mix either.
    • Do an experiment like concept 2, except with vinegar and oil.
  • Experiment 9: A Jar of Bubbling Goo. (See more details here.)
    • Make baking soda ice cubes. Fill a container with an inch of vinegar and an inch or two of oil. (You can re-use your mixture from experiment 8.) Drop in a baking soda ice cube, and watch it bubble and ooze.
  • Experiment 10: An emulsifier can connect vinegar and oil
    • Beat together oil and vinegar – they won’t stay combined. Add an egg yolk. Beat with an electric mixer… for a while, nothing happens, then suddenly, it will turn into a mayonnaise like substance – the egg yolk is the emulsifier which holds the oil and vinegar together.
    • You can also make real home-made mayo (find recipes online).

Acids and Bases

Introductory Experiments:

  • Taste: give your child a spoonful of lemon juice or lemonade. Ask them to describe the taste – is it sour? Then give a spoonful of milk? Is that sour? No. Acidic things taste sour, base things do not.
  • Smell: Have them smell lemon juice and vinegar – strong smell wrinkles up their nose. Have them smell milk, and soapy water or bleach water – milder smell.
  • Feel: make small dishes full of vinegar, lemon juice, soapy water, and bleach water. Have them try rubbing the fingers of their left hand in the vinegar and lemon juice, and the fingers of their right hand in the soapy water or the bleach water. The base items (soap and bleach) make their fingers slippery.

Reactions:

  • Baking soda and vinegar react. Mix some together in a dish. Observe the reaction. What do you notice? (Fizzy sound and foam.)
    • you can also cover a shallow tray with baking soda, then mix vinegar and food color or liquid watercolor and let them drip the vinegar on the baking soda with pipettes
  • When baking soda and vinegar react, they create a gas. Do the self-inflating balloon experiment described here. Explain that the reaction is creating a gas which is filling the balloon.
  • When gasses expand they can fill a space. You could put vinegar and baking soda inside a test tube with a stopper or a bottle with a cork. As the gas expands, the container will blow its top.
  • Make Ziploc time bombs: www.geeksraisinggeeks.com/quick-science-experiments/
  • Make baking soda ice cubes (make a paste of baking soda and water, freeze it.) Then drop one in a container of vinegar for a “time release” reaction
    • Then put oil and vinegar in a jar with some food coloring. Add a baking soda ice cube for a jar of bubbling goo (see video here.)
  • It’s not just baking soda and vinegar that react – most acids and bases will react
    • Do erupting lemons experiment described here
    • Curdle milk (a base) with lemon juice (an acid). Then make milk plastic with it, as described here

Testing for Base vs. Acid

  • There are multiple ways to test whether a substance is acid or base. You could, of course, use litmus paper or ph paper.
  • You can also make an indicator using red cabbage. Learn more here or here.
  • Or you can make an indicator with turmeric

Chemistry: Reactions

[An updated version of this post is at https://inventorsoftomorrow.com/2016/12/22/chemical-reactions-for-kids/]

In our last session, we covered Mixtures and Solutions. This class was all about Reactions. One of the great things about most of these experiments is that they’re really easy for parents to re-create at home with inexpensive materials you probably already have in the cabinet.

Some of the reactions are quick and dramatic, others are more slow and subtle and require a little patience to observe. Before you start experimenting, you may want to do a very brief explanation of reactions: “we’ll mix two or more ingredients together, then we sit back and watch and see what happens. Sometimes something happens right away – sometimes we’ll have to count to ten and see what happens.”

What’s the Big Idea: When some chemicals are mixed together, they “react” and the substance changes in some way. That’s the fundamental idea we’re hoping that our 3 and 4 year old students grasp.

As you might guess, we’re going to use lots of acid and base reactions in this class – vinegar and baking soda, lemon juice and baking soda, lemon juice and milk, etc. If you have 6 and 7 year old students you can explain more about why those react. There are lots of ways to explain this (see some here on the UCSB Science Line). You might say “vinegar and baking soda both have energy they don’t want and they can help each other get rid of it. Vinegar is an acid and it wants to give away a proton. Baking soda is a base, and it wants a proton. When they meet, the baking soda grabs the proton, and then they release a water molecule and some carbon dioxide gas, which makes the bubbles.”

Question of the Week: What are the signs of a chemical reaction? Answer: Some examples are – the color changes, there’s a different smell. there’s a change in shape or texture, a change in temperature (it becomes warm or cold), the substance makes sounds, or it starts giving off light.

You can use baking soda and vinegar as your example: When these are mixed, they produce foaming bubbles (and carbon dioxide gas) and also make a fizzy sound. If you mix them in a plastic bag, and seal it, the children can also notice that it is an endothermic reaction – the mixture gets colder as it reacts.

Classroom Activities

A Jar of Bubbling Goo (Vinegar, Baking Soda, and Oil): This is really cheap and simple, yet really dramatic – check out the video at the top of this post! Some of our students loved this so much they wanted to do it over and over. It requires some advance preparation of making baking soda ice cubes: Use water, baking soda and blue food coloring to make a thin paste. Freeze in ice cube trays.

At class: Pour into a jar one inch of white vinegar, two inches of vegetable oil, and a few drops of yellow or red food coloring. Point out that the oil and vinegar don’t mix – this is a flashback to last week’s class when we learned water and oil don’t mix. Then drop in a baking soda ice cube. Sit back and observe. As the baking soda and vinegar react, they release lots of bubbles. Note: you can set a lid on top of the jar but don’t screw it down – you want the gas to be able to escape, not build up pressure.

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“Lava Lamps” Another bubbling bottle activity we didn’t do in class is to pour oil, water, and food coloring into a jar or water bottle. (Like the “Fireworks in a Jar” activity mentioned in last week’s post.) Then add an alka seltzer tablet. Here’s how Steve Spangler describes the science of what happens: “the Alka-Seltzer tablet reacts with the water to make tiny bubbles of carbon dioxide. These bubbles attach themselves to the blobs of colored water and cause them to float to the surface. When the bubbles pop, the color blobs sink back to the bottom of the bottle.” It’s infinitely re-useable. Any time you want more bubbles, just add another Alka-Seltzer. If you don’t have Alka-Seltzer, Hands On As We Grow says salt works too. To find pictures of this in action, search for “lava lamp science project.”

Fizzing Powder: Fill a shallow tray with baking soda. Then mix liquid watercolors with vinegar. Let the children use pipettes, eye droppers, turkey baster, or spray bottles to drip colored vinegar on the baking soda and watch it fizz. (Note: we tried taking coffee filter prints of the product, but it wasn’t a very interesting art project, so we decided to just leave it as the basic tray of fizzy powder activity.) See more pictures of this at Hands on as we grow and Creatively Blooming.

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Engineering Discovery – Making Plastic from Milk.

  1. Heat one cup of milk in the microwave till it’s quite hot, but not boiling. (90 seconds?)
  2. Add four tablespoons of lemon juice or vinegar. (Our math practice for this week is this measuring and counting needed for this recipe.)
  3. Stir for about one minute till it curdles.
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  4. Put milk in a strainer, press out as much moisture as you can. Discard the liquid.
  5. Then put clumps on paper towels, and squeeze out all the moisture.
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  6. Either press into a mold, or flatten into a slab and cut with a cookie cutter.
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  7. Let dry for a few days.

 Self-Inflating Balloon – Blow up a balloon with a chemical reaction.

  1. Pour one inch of vinegar into an empty water or soda bottle.
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  2. Then spoon a small amount of baking soda into a balloon. (Optional tool of the week: you could use a funnel to make this easier.)
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  3. Put the balloon on the top of the bottle, being careful to have most of the balloon dangling off the side so the baking soda doesn’t fall into the vinegar too early.IMG_20160409_103718366
  4. Once balloon is attached, hold it up. Shake it so the baking soda falls into the vinegar.IMG_20160409_103734142
  5. Sit back and watch the reaction. As bubbles form, pop, and release gas, the balloon will inflate. (The balloon also gets colder.)
    balloonexpands
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You could try this experiment with other liquids. What happens if you put water in the bottle instead of vinegar? [Nothing.] What if you use lemon juice? What if you add detergent or bubble solution to the vinegar? [You end up with a balloon full of bubbles…]
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There’s a great description of the science of this experiment on the Science Club website: http://www.webinnate.co.uk/science/week2.htm.

Extension: you could see what happens if you “turn this around”: put baking soda in the balloon, use a pipette to squirt vinegar into the balloon, then hold the balloon closed.

Sensory Tub – Erupting Lemons: Partially core a lemon. Sprinkle some baking soda into it. It will produce a fizzy mini-eruption. If you want more reaction, squeeze the lemon to release more juice, or add more baking soda.

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Art Activity: We reprised “Milk Fireworks” from last week just because it’s so fun and easy and we had leftover milk. I wish I’d found this post on Babble Dabble Do before class: it talks about how to make marbled paper with the milk fireworks.

Glitter Volcano: If you have a child who loves pink and sparkly things, then get the prettiest clear bottle you can find. Put in baking soda, then just a little red food coloring, then some pink or silver glitter. Then add vinegar. It’s a pretty and sparkly chemistry experiment. (Source: Geeks Raising Geeks.)

Big Motor Activity / Snack Prep – Make Ice Cream. Mix 1 cup of whipping cream, 1 cup of half and half, 1 tsp vanilla and ¼ – ½ cup sugar. Put in a small container with an airtight lid. (If it’s not watertight, seal with tape.) Put it inside a bigger round container (like a coffee can.) Fill the large container with layers of ice and rock salt. Roll the can back and forth between students (or up and down a slide) for about 15 minutes till ice cream hardens. Then eat it! (You can also make ice cream in Ziploc bags – see our directions in the States of Matter post.)

Circle Time

We explained the big idea and discussed the question of the week, discussed at the top of this post. We didn’t have a song of the week, because we didn’t find any good songs on chemistry reactions – if anyone knows of one, let me know!

Recommended Books. As with last week, we found it challenging to find many kids’ books about chemistry. Here is the one we used.

  • The Secret Science Project That Almost Ate the School by Sierra and Gammell. A silly story about kids preparing for a science fair. Our protagonist has no ideas for projects. She orders a super slime from the internet that eats her cat, her sister, her teacher… and is finally vanquished when the children feed it too many sweets.

Group Parachute Game: Endothermic and Exothermic Reactions: Have all students stand in a circle and hold onto a parachute. Toss some balls in the middle: One person flicks a spinner with red or blue spaces. If it comes up red, students imitate a ‘hot’ excited exothermic reaction with balls bouncing up and down, if it comes up blue, they imitate a cold endothermic reaction by slowly rolling the balls around the center.

Naming Your Experiments

We’ve noticed that kids tend to engage more with an experiment if it has a good name. For example, the “Egg Drop Challenge” is more likely to engage than saying “over at that station, you’ll make a container to protect an egg, and then try dropping it.” The “Dino Dig” is better than “go rummage through that shredded paper and find the plastic dinosaurs.” This week, we were calling the vinegar, oil, and baking soda ice cube experiment  “Fireworks in a Jar” and the kids were very excited by that name, and were talking about it over and over. “Erupting Lemons” was also exciting.

So, I’m thinking about names, and they’re tricky sometimes. For example, if you say to any American over the age of 10 “I made a volcano in science class”, they all know that you mean you did a baking soda and vinegar reaction. Maybe in a papier-mâché volcano, but maybe just in a dish. But when you think about it, it’s probably not right to call a baking soda and vinegar reaction a volcano, since it really has nothing at all to do with the hot lava and volcanic ash that comes from a volcano.

After we spent the day calling our experiment “Fireworks in a Jar”, I discovered that online, lots of people use that term to describe an experiment I added to last week’s post on Chemistry Solutions that is water, oil, and food coloring that sinks through the layer of oil and diffuses in the water, looking more like fireworks than our bubbling experiment did. So, I thought of changing the name to Lava Lamps, but discovered that online, that’s usually used to describe an experiment with oil, water, and Alka-Seltzer (see above). I thought about using the word magma, because the red jar at the end of the video reminded me of magma. Or, even better, Magma Mines, which is the name of one of my son’s favorite levels in Mario Party. But, again, that would be scientifically inaccurate, since bubbling vinegar, oil and baking soda have no relation to molten rock. Can’t call it Boiling Bubbles either, because it’s cold, not hot. So, I’ve settled for now on “A Jar of Bubbling Goo.”

Over time, I’m hoping to go back through old posts, and think of good names for all our experiments, because it definitely makes a difference in how “fun” the kids perceive the experiment will be.