This hands-on science activity is great to kick-off the Halloween season! As with all science activities, safety is extremely important! You must wear safety goggles for this activity. Parent supervision is required.
This activity makes a lot of mess, so be certain to wear old clothes and lay down newspaper!
Supplies You’ll Need:
- One empty 12 oz plastic soda or water bottle (remove the label)
- One plastic table cloth or baking sheet (this experiment gets MESSY)
- 1/2 cup of 20-volume hydrogen peroxide (do NOT go higher in volume – this experiment produces heat. 20-volume will cause a lukewarm reaction)
- 1 packet of dry yeast
- 3 tablespoons of warm water
- Liquid dish soap
- Green food dye (but any color will work)
- Safety goggles
- A carved pumpkin!
Note: Feel free to add glitter if you so choose! (and only if you are brave)
- Pour 1/2 cup of the hydrogen peroxide solution into the empty plastic soda bottle. Since this solution is 6% hydrogen peroxide, it can irritate the skin. We recommend having the adults pour the solution into the bottle for the children.
- Add 1 tablespoon of liquid dish soap to the plastic bottle.
- Add 8-10 drops of food dye to the plastic bottle and mix the bottle by swishing it around.
- Place the plastic bottle inside the jack-o-lantern. Place it close to the opening of the pumpkin’s mouth.
- Open the packet of yeast and pour it into a separate small cup.
- Add the warm water to the yeast and stir.
- After 30 seconds, carefully pour the yeast mixture into the plastic bottle with the hydrogen peroxide mixture.
What Is Happening?
If you have completed the previous steps, you’ll notice that green foam essentially erupted from the plastic bottle and oozed out of the jack-o-lantern’s mouth! Also, if you touch the foam you will notice that it is warm to the touch! That’s because the chemical solution that you created was produced by a fast-acting, rapidly expanding, exothermic reaction! Say again?
The hydrogen peroxide has lots of oxygen inside of it. When you added the yeast mixture to the hydrogen peroxide mixture, the yeast acted as a catalyst to remove the oxygen from the hydrogen peroxide. Since it happened really fast, the two mixtures created lots of tiny bubbles that then became foam. Not only did you create bubbles and foam, but you also created heat! Mixing the two mixtures together caused the final solution to release energy in the form of heat. That is what an exothermic reaction is!
Note: Have your children attempt to scoop the foam back up into the bottle or into the pumpkin’s mouth.
- Mixture – (n.) a material that is produced by mixing two or more different substances while not being combined chemically.
- Catalyst – (n.) something that causes or accelerates a certain event to occur without experiencing any change to itself.
- Energy – (n.) the ability to do work.