38- Ice Cream Lesson

Today I taught a Science lesson on properties of matter. We have been learning about matter all week, specifically how matter can change from a solid to a liquid to a gas. As a little celebration, I planned for the students to make ice cream. On the internet, I found an easy recipe for vanilla ice cream and the procedures seemed simple enough for my class to follow. To avoid mass hysteria and chaos, I decided not to tell them what we were making.
The lesson was messy. We started out by pouring lots of heavy cream into a bucket with a little vanilla extract. Next we added sugar. I let the kids take turns stirring our mixture and we talked about if we thought the sugar would melt in the cream. The night before, I had packed 24 individual gallon sized baggies with ice. My class and I discussed what happens when you pour salt onto ice, and then I let each kid throw a large handful of rock salt into their own bags of ice. I had to work fast to do step three, which was pour one cup of the liquid cream and sugar mixture into small, individual baggies for each child.
As soon as a kid received his or her tightly closed, little baggie of cream and sugar, they were to place it inside of their salt and ice baggies. Then they zipped up the gallon baggies and shook with all of their might. It was fun; the kids jumped and shook their bags wildly. Despite all the frozen fingers and spills, the students were enjoying themselves.
Hannah was the first to notice a change in her matter. “Hey, my cream is starting to get all stiff.”
One by one, the kids realized that their baggies of cream were no longer liquid. This excited them even more. They furiously shook their baggies, curious to find out what would happen.
Miraculously, my internet lesson had proven true. Without fail, all of my students were holding bags of frozen ice cream. We talked about how the salt had helped turn our solid (ice) into a liquid (water), but that at the same time the cream had changed from a liquid to a solid.
The students were enthused. One kid called out, “Hey! Did we make ice cream? There was cream, but now it’s solid! Ice cream!”
I told them that they had just made ice cream. I handed out spoons, and the kids tore open their baggies, eager to taste their creations. Salty water splashed all over the desks and carpet, and I vowed to bake Mr. Love an apple pie for the mess he would have to clean. It’s small price to pay for all the learning that went on in my classroom today. And the ice cream tasted great!