100 Days Project

Nanogirl: Star Science

Nanogirl wants to find 100 friends to do science experiments with her to prove that no matter who you are or what your education level, you can always have fun with science.

Day 23:

10 year old Rebekah makes soap soufflé!

Rebekah is 10 and today she showed me a fantastic experiment using a special soap and a microwave.

Ivory soap is a special brand of bar soap that floats in water unlike other soaps that sink. Right now it's only available in America however Rebekah was lucky to have had some brought in for her. Ivory soap floats because its whisked and has air pumped into it during the manufacturing process meaning its full of tiny bubbles, however if you look at it they are too tiny to see.

Rebekah first put the Ivory soap in a jug of water and watched it float, she then put a normal bar of soap in the jug and it sank.  Next she put the Ivory soap in the microwave and set it to high for 2 minutes, and we all watched as the soap expanded, and expanded and grew into a huge fluffy looking structure.

Inside the tiny air bubbles are air which contain water and this trapped water vaporizes (turns into a gas) when the microwave is turned on causing the air inside the bubbles to expand with the heat creating bigger bubbles.
In science we know this as Charles' Law which states that as the temperature of a gas increases, so does its volume. When the soap is heated, the molecules of air in the soap move quickly, causing them to move far away from each other causing the soap to puff up and expand to an enormous size.

When a normal bar of soap was put in the microwave it just melted into a horrible stinky mess because it didnt have any trapped air to expand.