Most people are familiar with the fun science experiment where you microwave a bar of soap to see what happens.
The soap grows bigger and bigger into a sort of giant soap cloud, which kids can poke and squish (and even use in the bath or shower).
It’s important when we do fun science experiments with our kids that we also explain the reason behind the reactions, though. It’s even better when we can help kids figure it out on their own.
Here’s how to do the basic Ivory soap experiment, courtesy of Steve Spangler science.
It’s great that he starts the experiment by having kids drop a piece of Ivory soap into a bowl of water along with a piece of another soap, because this allows kids to start figuring out what makes the Ivory soap different (the fact that lots of air is whipped in).
He also goes into the explanation of why it works:
This is actually very similar to what happens when popcorn pops or when you try to microwave a marshmallow. Those air bubbles in the soap (or the popcorn kernels or the marshmallow) contain water. Water is also caught up in the matrix of the soap itself. The expanding effect is caused when the water is heated by the microwave. The water vaporizes, forming bubbles, and the heat causes trapped air to expand. Likewise, the heat causes the soap itself to soften and become pliable.
He even goes into Charles’ Law, which states that as the temperature of a gas increases, so does its volume.
Once you get all that fun out of the way, you can make it even more fun by adding some color.
Give the kids any of these materials:
- Liquid watercolor paints and eyedroppers
- Squeezable food coloring bottles
- Small containers of paste food coloring diluted in water (mini muffin tins and ice cube trays work well, as do little jars) and pipettes
- Watercolor paints, a paintbrush and a small jar of water
Be sure to protect your workspace and put them in crafting clothes, as these materials can stain.
Then just let them drop or paint the colors onto the Ivory soap cloud to create color combinations and make a little bit of impromptu art.
You can ask them to make hypotheses about how the soap clouds will react to the colored water, to further expand the lesson.
How do you think the soap cloud will react to the colored water?
What do you think will happen if you drop two colors in the same spot?
Do you think this can still be used to wash hands?
Keep in mind that the painted soap clouds may stain things they come in contact with, including skin and bathtubs. Make sure to use washable products if you want to keep the colored soap clouds for use in the bathtub or sink later.