Friday, July 30, 2010

Making Ice Cream: A Lesson in Thermal Energy Transfer.

A hot summer afternoon can leave my body craving ice cream!....Currently my favorite flavor is Mint Patty from Golick's Dairy Bar in Dover NH. My husband is more a Strawberry Cheesecake fan at the moment.

While it is simple to order a cup or a dish from a local stand, it is more fun to make your own! If you are baby sitting for the summer or have younger siblings, you can even make an afternoon out of it! Be sure you are ready for the vigorous shaking, it can be a real work out....

So here is how making ice cream is science! (View the video provided for instructions and recipe)

The outer container is used to house the ice. Ice melts naturally because thermal energy (heat) likes to move from "hot" to "cold" places (high to low concentrations). So the thermal energy from the environment wants to transfer (move) to the ice which has less thermal energy. When heat is added to the ice it breaks the bonds in the ice and causes it to change state, from a solid to a liquid (melting). Salt is added to the ice in the outer container to depress, or lower its freezing point.....making it even colder and the melting process slower!

Another transfer of energy occurs simultaneously. The yummy mixture in the inner container has more thermal energy than the outer container, so again, heat transfers from the inner container to the outer container. When heat is removed from the inner container the mixture changes phases from a liquid to a solid! Yum!

Finally by shaking it with you hands, you are adding even more energy into the universe and speeding up the process!

Enjoy!

3 comments:

  1. Cool blog, Meredith! You have an engaging writing style and I learned some things already. Very nice!

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  2. Thank you for writing blogs! They are so interesting!

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  3. I make way better ice creams with my own ice cream machine.

    -Teky

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