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Weather experiment with exploding soap

Posted at 12:46 PM, May 04, 2020

Have you ever wondered if a bar of soap can explode in the microwave? Making soap explode is super simple and a lot of fun! Plus we can learn 2 different ideas…something called Charles law and how thunderstorms form. Lets get started!

What you need:
- Plate
- Microwave
- Bar of ivory soap

Step 1: place bar of ivory soap on the plate

Step 2: microwave soap for 1-2 minutes

Step 3: watch what happens!

So cool! Ivory soap is one of the few brands of bar soap that floats in water and can explode like this in the microwave because air is whipped into the soap during the manufacturing process. This means there are tiny little pockets of air all throughout the soap.

How does is expand like this in the microwave? It works similarly to popcorn kernels or marshmallows expanding in the microwave. The little air pockets contain water molecules that are heated up by the microwave. The water then vaporizes and the heat causes the trapped air to expand.

This showcases Charles law which states the temperatures of a gas increase so does its volume. So when soap is heated the molecules of air in the soap move quickly causing them to move far away from each other forcing the soap to expand.

This whole experiment can be related back to thunderstorms…. Warm air rising and the cold air condensing and sinks. This quick motion of the cold air sinking makes things unstable and that how we get strong thunderstorms to develop. Same thing here the warm air is rising its less dense and expanding.

This experiment only works with ivory soap due to those tiny little air pockets. Other soaps won't float in water and typically melt or smoke possibly ruining the microwave. So be careful!

There you have it, exploding soap!! Send our meteorologist Candace Monacelli your pictures doing this experiments at home! She will feature future meteorologists on my facebook page daily!