Tuesday, July 19, 2011

I Scream, You Scream, We All Scream for a Science Project!

I've always known that you could make ice cream in a Ziploc bag, but I had never actually tried it. Until now. It is sooooo easy!

Fill a small, zip-top freezer bag with 1 cup of half-and-half, 1/4 teaspoon of vanilla and 1/4 cup of sugar. Insert the small bag (after squeezing out the air and sealing it) into a gallon size freezer bag full of ice and coarse salt. Shake for ten minutes and voilĂ ! You've got ice cream!

In addition to being delicious (truthfully, it was delicious. The consistency was not great, but the flavor was as good as any vanilla ice cream I've had.) and fun, this project is science in motion! My kids have already been exposed to the effects of salt on ice. This took it to the next level by showing them energy molecules at work. No, they don't quite understand that ice was absorbing heat energy, thereby melting, and then the water molecules used that energy to freeze again, but the salt made it difficult, so it had to work harder thereby making the ice colder which caused the cream to freeze. But they have some sense that something happens when salt and ice interact and that whatever it is can cause cream to freeze! Not bad for people around three feet tall.

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