To introduce students to the contrast between making a new material and changing the form of an existing one; to demonstrate that matter can be changed from one form to another (liquid to solid) but still be the same.
1-lb coffee can with plastic lid
Junior-size baby-food jar
Salt (rock or table)
Crushed ice, about 1 lb per student
Metal or wooden spoon
Enough chocolate milk to fill each jar 2/3 full
Newspapers to catch the mess
Sponge to clean off the jar
And have your students bring in a pair of gloves from home
1. Fill each jar 2/3 full with milk and close the lid tightly.
2. Pack salt and ice in the bottom of your coffee can (for older students, have them determine the amount of salt needed for a 1- to-2 ice and salt ratio). Put your jar in the center of the can. Pack ice around and over the jar so it is snuggly set. Cover the can with its lid.
3. Wearing gloves, shake the cans until the milk freezes (10-15 minutes). Check the work in progress to see it changing forms.
4. Discuss that the ice cream is the same material that they started with; it has just changed forms. How can it change back? (Melting!)
- Math comes in with measuring milk, salt, and ice.
- You need Reading for the directions. Look up "Eighteen Flavors," a poem by S. Silverstein in Where the Sidewalk Ends (Harper and Row, NY, 1974).
- Writing can easily be added by having students write a poem about their favorite flavor of ice cream.