FOX 17 UnfilteredWeather Kids


Weather Experiment: Exploding soap with Mattawan Consolidated Schools

Meteorologist Haleigh Vaughn visited Mr. Ablao's and Mrs. Salvatore's 6th-grade classrooms
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Posted at 7:00 PM, May 16, 2023

WEST MICHIGAN — Two things that we might have at home right now is a bar of soap and a microwave. When put together, those two items can help us understand Charles Law and how thunderstorms form.

Meteorologist Haleigh Vaughn visited Mr. Ablao and Mrs. Salvatore's 6th-grade science classrooms at Mattawan Middle School to share with the students why a bar of soap explodes in the microwave. You can watch the experiment in the video above!

Looking to try this at home? Here is what you'll need:

1. A plate
2. Microwave
3. Bar of Ivory soap

Here are the steps:

Step 1: Place the bar of Ivory soap on the plate
Step 2: Microwave soap for 1-2 minutes
Step 3: Watch what happens!

Ivory soap is one of the few brands of bar soap that floats in water and can explode in the microwave. The reason is that the Ivory bar of soap has air whipped into it during the manufacturing process. This means that there are tiny little pockets of air all throughout the soap.

You might be wondering how the bar of soap expands so much 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 additionally showcases something called Charles Law. Charles Law states that as the temperature of the gas increases, so does its volume. When the soap is heated up, the molecules of air in the soap move quickly. This causes them to move far and away from each other, forcing the soap to expand.

This experiment can also be related to thunderstorms! Warm air naturally rises, while cold air naturally condenses and sinks. The motion of the air rising or falling can create changes in our weather. Have you ever noticed the tall head of a thunderstorm cloud? Well, that is because the thunderstorm developed in a warm environment. The air was able to rise, creating the top of the thunderhead.

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 ... which could ruin your microwave. So, be careful! If you want to try this experiment at home, purchase Ivory soap.