Mme Green's Classroom: I SCREAM!!

Today we made ice cream in my grade 7 science class to show how salt changes the melting point of ice and thus makes it even colder and helps make ice cream even quicker.

I was loud, messy, and delicious!!! We figured out why some group's ice cream worked and other's didn't and talked about all of the experimental errors. The kids enjoyed adding toppings and various flavorings too.

Perhaps a fun idea for "Family Day Unplugged" - Remember to have the kids submit their forms for hours spent together "unplugged" from technology so that we can win a prize!! A pizza or pool party!!

Here is the scientific explanation and recipe from http://chemistry.about.com/cs/howtos/a/aa020404a.htm

Ice has to absorb energy in order to melt, changing the phase of water from a solid to a liquid. When you use ice to cool the ingredients for ice cream, the energy is absorbed from the ingredients and from the outside environment (like your hands, if you are holding the baggie of ice!). When you add salt to the ice, it lowers the freezing point of the ice, so even more energy has to be absorbed from the environment in order for the ice to melt. This makes the ice colder than it was before, which is how your ice cream freezes.