Electricity

There is an updated version of this post at https://inventorsoftomorrow.com/2016/11/14/electricity-2/

Question of the week: What are the ways we create Electricity and what do we do with it?

Here are the activities we used to explore electricity:

Electricity Experiments

Challenge: Can you create an electric circuit using play-dough?
We made two batches of play-dough, one conductive and one insulating. (See recipes: www.instructables.com/id/How-to-make-conductive-play-dough/?ALLSTEPS.) Students stick battery pack wires and a pre-wired LED into the dough and experiment with which completes the circuit and lights the light. Once they learned which dough would conduct the electricity, we wanted them to play with it a bit longer, so we had them test several lights, and sort the lights by color. There’s a lot more you can do with “squishy circuits” made of play-dough. Here’s a video of a TED talk on why squishy circuits are cool for kids. http://courseweb.stthomas.edu/apthomas/SquishyCircuits/

Lighting a Bulb: Use 9 volt batteries, and lightbulbs on wires. Connect the wires to light up the bulb and show how a circuit is completed. We also had mechanical switches and DIY switches we could include in the circuit. (If you don’t already own these materials, there are several simple kits that include the basics, such as School Specialty 560962 or the Eisco Labs kit.)

bulb

Lemon Battery: So, on many websites, and in many kids’ books about electricity, you’ll find directions for a lemon battery – you put a penny and a zinc screw in a lemon, and use it to light a lightbulb.
The science behind this is something like this: What’s happening in a voltaic battery: two electrodes – one copper and one zinc – are submerged in an electrolyte – an acidic solution (lemon juice in this case). Zinc and lemon produce electrons and copper and lemon lose electrons. Electrons pass through the lemon juice from one battery terminal to the other, creating electricity.
The idea for the experiment is: roll the lemon with some pressure to get it juicy, then insert into the lemon one zinc item (screw or eyelet) and one copper item (copper wire, rivet or copper penny – from before 1982 when pennies were more copper than zinc). Be sure the two metals don’t touch. Then take a lightbulb on wires – touch one wire to the zinc item and one to the copper to light the bulb. (Or so several sites / books claim.) We found that the current produced by the battery was way too weak to light even a very low voltage LED. We did get a voltmeter which could measure the current to show a reaction was happening. This website claims that if you touch your tongue to the copper and zinc, you’ll feel a slight tingle and taste a metallic tang. We did not attempt this.

Playing with Electrical Tools / Toys

Create electricity with a hand generator: We had a crank-powered flashlight and emergency radio plus several small flashlights with dynamos. (Like these, but we got ours in the Daiso dollar store for $1.50 each.) These were a great free play activity for the active kids – we turned off most of the lights in one room and they just played with flashlights and did flashlight tag.

Plasma ball: We had one of these to let kids see the “lightning”: Sphere Lightning Lamp

littleBits: We had the littleBits Electronics Base Kit. littleBits is kind of the Lego of electrical circuits. It’s a modular system, with little bits that click together with magnets, so it’s easy to assemble them correctly. (They say they’re for ages 8 and up, but my five year old can do everything with them, and even the 3 year olds could handle the basic concepts.) There are inputs (buttons, dimmer switch / volume control, sound activated switch, light sensor switch, remote controllable switch), and outputs (lights, buzzers, motors, etc.) The base kit comes with an instruction book to explain the basics, but also “ideas to get you started” on other things you can invent with them. The goal is to encourage tinkering. There’s lots more info about them on Amazon.

Here is a basic configuration: power cell, input switch (a push button) and an output (a bright LED light.)

IMG_20160111_194953046

Here is another simple set-up of power module, wire, and motor. But, we’ve attached the motor to a windmill propeller, and mounted it on a little popsicle stick building. When you turn on the power, the propeller rotates.

IMG_20160111_191458454

I have to say: I LOVE the littleBits. They’re a great toy that my five year old really enjoys and learns from. But… they’re stupidly expensive! I am hoping that over time, with economies of scale, (and likely competitors) the price comes down. But for now they’re quite pricey. Snap Circuits is another modular electronics kit I have heard of, but I haven’t had the chance to experiment with it.

Cheap Toy: Ok, I know you’ve all seen toys during your life where if you touch two metal contacts on the bottom, it completes a circuit and the toy does something. (My daughter got a toy chick one Easter that would chirp when you held it in your hands.) I’m now searching for a toy like this and haven’t found one. (Other than these “liquid activated” glasses.) But I want one, because when my daughter brought her chick to school (lo those many years ago), she and her classmates discovered all sorts of cool concepts about electricity by playing with it. For example, if one person touches one contact and another person touches the other, the bird does not chirp. But then when those two people hold hands (to complete a circuit) the bird chirps. The bird chirps when set on a metal surface but not if set on wood or rubber, and so on. I’d love to have been able to have the kids in our class do similar experiments.

Static Electricity

Weather Note: There’s lots of great static electricity activities you can do, but it’s worth noting that your success will depend a lot on the weather! We figured that in January, our classroom air would be quite dry due to all the forced air heat that was blowing through it. However, when the outdoor humidity is at 85% as it was last Saturday, your static electricity demonstrations will be less effective than you had hoped…

History and an Experiment to Go With It: 2,500 years ago a Greek mathematician and astronomer named Thales (TAY-less) first noticed the effects of static electricity. He was polishing a piece of amber, with a piece of wool or fur. Thales discovered that after he rubbed the amber that it attracted dust particles or other light objects like straw or feathers. (More history here: http://inventionofelectricity.weebly.com/contributors.html)  You could re-create this in class with amber, sheep skin, and feathers.

Balloons and static: It’s easy to generate static electricity by rubbing a balloon on hair – you can then hold the balloon near your hair to make it stand up on end, or stick the balloon to a wall, or use the balloon to pick up small lightweight bits, such as puffed rice cereal or torn up tissue paper. You can also have a plate of salt and pepper. Wave the static charged balloon over it – the pepper will fly up first, and the heavier salt will be slower to attract. You could have a contest where kids stick their balloons to a wall, and see whose balloon stays stuck the longest.

Combs: You can rub a plastic comb with wool or silk to create static, then use it to pick up feathers, cereal or tissue paper, pepper, etc.

Light a bulb with static: Our teacher rubbed a balloon on her hair to build up a static charge, then held the balloon to one end of a compact fluorescent bulb, and it made it light up briefly. (Better in the morning class before the humidity spiked outside!) Learn more at: http://www.csiro.au/en/Education/DIY-science/Physics/Light-up-your-light-bulbs

Make Lightning: http://www.learnplayimagine.com/2013/04/how-to-make-lightning.html has two methods for getting a spark. We haven’t tested these.

Parachute: During circle time, you can use the parachute – have some kids stand under the parachute while the other kids and adults lift it up and down – pretty soon the kids’ hair will stand on end.

Water table: Have a static generator (balloon and hair, or amber and wool, or comb and wool) next to the water table. Charge it up, then pour a trickle of water past it – will the static electricity “bend” the stream of water?

Alternate water table idea: Put in scoops and water wheels. Put pictures of water wheel generators next to the table so you can explain how before the invention of electricity water wheels on streams were used to do work (like grind grain or pump bellows.)

Art: This topic didn’t lend itself to art as well as some other topics do. What we did:
1) drawings with Spirograph to represent electron orbits. 2) Scratch art pictures of lightning bolts… scribble with oil pastels to fill a piece of paper with bright colors. Paint over that with dark blue/black acrylic paint like the night sky. While the paint is still wet, use a stick to draw lightning bolts – it will move the paint aside to reveal the colors below.

Circle Time Concepts

We discussed the experiments they had tried, asked what they had observed, and discussed the basic ideas of electrical current, circuits, generators, and batteries.

Grounding in their Experience: For static, ask them: have you ever slid down a plastic slide and then gotten a shock when you touched someone? Have you ever played parachute games at circle – did you notice that for the kids who went under the parachute, their hair would then stand up straight? When your parent gets laundry out of the dryer, have you ever seen a sock stuck on to something? Then explain that is static electricity.

Pass the current: Have kids hold hands in a circle. Squeeze a child’s hand, they squeeze the next hand, and so on, to pass the current all the way around a circle.

Books:

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Books for Circle

  • Oscar and the Bird.  When Oscar the kitten finds a tractor in a field and accidentally turns on the windshield wipers, he is full of questions about electricity. Luckily, Bird knows the answers! With the help of his friend, Oscar finds out how electricity is made and stored, which machines need electricity to work — and why we always need to be careful around wires, batteries, plugs, and sockets. Ages 4 – 8.
  • Electricity: Bulbs, Batteries, and Sparks (Amazing Science). A little long, but otherwise a good circle book for ages 5 and up. (skip the “fun facts” when reading aloud.)
  • Switch On, Switch Off by Berger. Library description: Explains how electricity is produced and transmitted, how to create electricity using wire and a magnet, how generators supply electricity for cities, and how electricity works in homes. Ages 6 – 8. Probably too long for circle.

Good resource books for older kids (age 5+) and for experiment ideas. Not for circle.

Group Activities

Electrons: Explain that all things are made up of molecules (reminder of the states of matter activities last week.) All molecules are made of atoms. Atoms are made of protons and neutrons which hold tight together in the nucleus, and electrons are held loosely. Give each child a die (or a coin) where some/one side is labelled “proton or neutron” and one is labeled electron. On each turn, they roll their die or flip their coin, then pick it up. If it says proton or neutron, they run to the center of the room and huddle together. If it says electron, they orbit in a circle around the protons and neutrons.

Pass the Electron Game: This idea started with an idea on Hub Pages: http://hubpages.com/education/electricity-lesson-plan  Have all the kids stand in a line. Tell them they are a copper wire. Give each one electron (a ball or other small toy). Tell them they’re a balanced copper atom. But, when the battery (the teacher) gives an extra electron to one child, they have to pass it on as quick as they can. When the extra electron gets to the end of the line, flash a flashlight to show the electricity was discharged. We tried this in our morning class – the teacher told them that they should take the new electron in their left hand, pass the old one on, then pass the new one to the right hand. But it turned out that it was too much of a small motor challenge for our three and four year olds – they had a hard time transferring balls from hand to hand. There are two ways to fix that. One is that they hold THEIR electron in their left hand the whole time and always use their right hand to take and pass the new electron. The other is what we did in our afternoon class, where we just pretended they were holding their own balanced electron, and the only moving ball was the extra electron that was passed to them. We were then able to pass several electrons at once, for a “hot potato” style game. You can also curl the end of the circle to complete a circuit.

 

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