For this 15 minute focus, we played with chemical mixtures and reactions. I normally have a 2 hour long class on mixtures and 2 hours on reactions, with tons of hands-on experiences. This, instead, is just a demo. Kids get to practice the “eyes-only, no-hands” skill that they’ll end up needing a lot in grade school! Before I get the materials out, I tell them about this expectation, and with this advanced coaching, they can do a great job!

Objective: children can describe a few examples of what might happen when you mix different materials together.

Sample Supplies

• 2 water bottles, one full, one half full
• a bowl
• marbles (or other small toy)
• salt
• glitter or sequins
• dry tempera paint
• a few ounces of vegetable oil in a water bottle
• food coloring
• alka-seltzer
• vinegar
• baking soda
• cabbage water
• paper towel

Demo

You can really do almost any collection of these items you want to do. These are just ideas. Or you could split it into two sessions: mixtures and reactions. Doing them all at once probably took me 20 minutes?

Mixtures

First, I told them we were going to try mixing different things together and seeing what happened.

I poured some water from the full bottle into the bowl, then mixed in some marbles. I asked them if they were mixed together forever or if I could take them apart again – they said I could take the marbles out of the water – I did. I asked if they were changed in any way – they pointed out that they were wet – I dried them, and then asked if they were different than before I put them in the water.

Then I added salt to the water in the bowl. They could see the grains of salt, but then I stirred. Where did the salt go?? We learned the words dissolve and solution.

I added glitter to the water in one of the bottles – does it mix? Nope – it floats. I put on the lid, and shook and shook – it would mix in temporarily (a suspension) but then separate out again as soon as I stopped shaking.

I added dry tempera paint (could also use the food coloring) to that same bottle, and shook it up – it dissolves and mixes in, but the glitter still floats.

I showed them the other water bottle. I explain that the food coloring is colored water – will it mix with the water? I add a few drops – it mixes. Can I take it back out? Nope.

I showed them the bottle of oil. I asked them what will happen if I add the food coloring to the oil. They think it will mix, but it doesn’t! The food coloring just beads up in the oil. Immiscible fluids!

I poured the oil on top of the water/tempera/glitter mix – what happens? The oil floats – it doesn’t mix in. (You can see this mix in the bottle in the back of this picture. (I think the bowl was soapy water and turmeric?)

Reactions

I mixed a little baking soda and vinegar in a bowl. We noticed the bubbles and fizzing sound – a reaction. We added a little more vinegar, then a little more baking powder, and so on. You could also include cabbage water in this time – it’s an indicator, and changes color from bluish purple to reddish purple depending on how acidic or base the solution is.

Note: The day I took the pictures, I had some turmeric which websites claim is an indicator that will turn red if mixed with something base (it stays yellow with acid); however, when I mixed it with both baking soda and with soapy water, nothing happened! Cabbage water is much better.

I added an alka-seltzer to the food coloring / water bottle. It makes bubbles / fizzy water! I explained that alka-seltzer is kind of like a dry mixture of vinegar and baking soda and when we add water, we get the reaction.

I added an alka-seltzer to the water/tempera/glitter and oil bottle. “Lava lamp“!

I thought this would be a super messy experiment, and had plastic tubs there to dump things into if needed, but it didn’t actually make much mess, and the kids really enjoyed it.

* There are lots of other things you could do here – check my sequence of experiments post for more ideas that could be adapted to this setting.