STEAM with
Ms. Amy

Pepper and Soap

Materials: A bowl or plate, water, (blue food coloring if you want to change the color of your water), pepper and soap.
1. Pour some water onto a plate or bowl. You want it to cover a large part of the plate.
2. Sprinkle some pepper onto the surface of the water. Observe what the pepper is doing? Is it floating on top of the water or sinking?
3. Dip your finger into the dish soap.
4. Place your finger in the center of the plate into the water.

Observe what happens when the soap touches the water? What happened to the pepper? Now is it floating or sinking? Before you added the soap, the pepper was floating. It can’t dissolve in the water because it is hydrophobic - it repels the water. The pepper floats because of surface tension - the water molecules are sticking together. But why does the pepper fly to the side of the bowl and some sink when you add the soap? The soap breaks down the surface tension of the water causing the pepper to sink. The water molecules want to keep together so they move away from the soap and take the pepper to the sides with them.

Further exploration: try adding other substances instead of soap to the water, like hair spray or olive oil. What are the results?

Link to the Website

Dancing Raisins

You will need: 2 clear cups, clear carbonated soda (Sprite), water and raisins
- Pour soda into one of the cups and water into the other cup.
- Add a few raisins to each cup, one at a time.

What do you observe? What is happening in each cup? What is different?

Why do the raisins dance in the soda? There are tiny bubbles of carbon dioxide in the soda. They attach to the uneven surface of the raisins. When enough bubbles attach to the raisin, it floats to the top. The bubbles pop at the surface and the raisins float back down and pick up more bubbles.

Further exploration: Try some dried pasta or fruit, corn, beans and beads.. Which ones do you think would dance in the soda?

Source: Chatterton, Crystal Ward. Awesome Science Experiments for Kids: 100+ Fun Stem / Steam Projects and Why They Work. Rockridge Press, 2018.

What happens when you add vinegar to baking soda?

Materials: 2 oz paper cups, baking soda, food coloring, vinegar, parchment paper, cookie sheet (If you don’t have cups, you could also use a cookie sheet)

• Fill each cup ⅔ full of baking soda

• Place each cup onto the parchment paper and cookie sheet

• Add a few drops of red food coloring to the baking soda and stir

• Do this with your other cups and food coloring

• Add some vinegar to each cup

What happens when the vinegar is added? Why is this happening? When you mix the two substances together, a chemical reaction occurs that produces carbon dioxide (a gas) and water. View the Website

Can you mix oil and water together?

Materials: jar with a tight lid, water, food coloring, cooking oil or baby oil
· Fill the jar half-way full with water
· Add a few drops of food coloring, stir
· Fill the jar the rest of the way full with oil
· Put the lid on the jar tight

What happened to the oil after you added it to the jar? What happens if you shake the jar? Where is the oil? Where is the water?

Why don’t they mix together? Oil is less dense than water. There are far more water molecules, which means the water will always drop to the bottom. Also, oil and water have different polarities. Water molecules are positive on one side and negative on the other. This causes water to stick to water. Oil is non-polar, and will only stick to non-polar molecules.

Further exploration: What happens if you add an egg yolk to the jar and shake the jar hard? view the Website

Fruit Boats

Can you make a boat with fruit, toothpicks and paper? Is there fruits that float? What fruit will you use: apples, oranges, bananas, pears, strawberries, kiwi or melons?

Will you need to slice the fruit in half, peel the skin off of one half and leave on the other half?

• Poke a toothpick through a piece of paper (cut into a triangle for sail).

• Poke a sail into a cut side of each piece of fruit. Put the toothpick in the skin of the fruits too.

• Once you are done building your boat, test it out in a large bowl of water.

What do you observe: Which fruits float? Which fruits sink? Does it matter if they have a peel?

Why do some float? Some fruits contain a lot of tiny air pockets. This makes them less dense than water, which means they will float.

Further exploration: Try cutting the fruit up into smaller pieces? Does this change the results?

Source: Chatterton, Crystal Ward. Awesome Science Experiments for Kids: 100+ Fun Stem / Steam Projects and Why They Work. Rockridge Press, 2018.