Teaching Science With Food
Here’s a fun little experiment that will teach your kids about how matter changes states. You begin with a liquid ice cream base that becomes a delicious solid in the form of ice cream.
This experiment also shows how salt reduces the temperature of water, speeding up the freezing process in the making of ice cream.
Indeed, making ice cream is really easy — you just need a few basic ingredients: milk, cream, sugar, and (in this case) vanilla.
You will also need rock salt, also known as ice cream salt. (You could also use table salt, but ice cream salt is better because the crystals are larger, meaning it will dissolve less.)
We used a recipe found in the book Smithsonian Maker Lab Outdoors written by Jack Challonor.
Ice Cream in a Bag
- dish towels
- 2, quart-sized zippered bags
- gallon-sized zippered bag
- plastic grocery bag
- 1/4 C. sugar
- 3/4 C. heavy cream
- 3/4 C. whole milk
- 1/4 t. vanilla extract
- 1 1/4 C. ice cream rock salt
- 3-4 C. ice
- To one small zippered bag add cream, milk, sugar and vanilla. Remove as much air as possible and seal.
- Now place this first bag into the second small zippered bag. This will help prevent any salt water from contaminating the ice cream.
- Pour the ice cubes and rock salt into the large zippered bag, then add the double-bagged ice cream base into the large bag. Remove the air from the bag and seal.
- Wrap everything in two layers of dish towels and place the completed bundle into the large shopping bag, tying with a rubber band.
- Shake and throw the bag for 15 minutes, or until the ice cream becomes solid.
- Carefully remove the ice cream bag from the salty water, wiping off any excess salt water. Open the inner bag and serve ice cream.