Here’s what you’ll need:
1/2 cup half-and-half (milk or heavy whipping cream may be used as substitute)
1/4 teaspoon vanilla extract
1/2 cup kosher or rock salt
1 tablespoon sugar
4 cups ice
1 small, sealable bags, such as a sandwich-sized Ziplocs
1 gallon-sized sealable bags
Here’s what you’ll do:
Place the salt and ice cubes in a gallon-sized bag and set aside.
In the small bag mix together half and half, vanilla and sugar. Make sure to seal the bag tightly.
Place the smaller bag into the bigger bag and seal both bags tightly.
Wear oven mitts or wrap the bag in a towel and shake for 5 minutes.
Every couple of minutes feel the smaller bag and examine what is happening to the ingredients.
Enjoy! Add some of your favorite toppings or save it in the freezer for later.
Learn how it works:
Freezing Points: The chemistry lies in the salt and ice mixture in the bag. Adding salt to the ice lowers the temperature at which water freezes. You will actually see your ice melting as your ice cream ingredients start to freeze.
Phases of Matter: This at home ice cream experiment changes the state of matter right before your eyes. The mixture begins as a liquid but changes to a solid as it freezes. However, the result can be reversed if you allow the ice cream to melt. This is a prime example of reversible change, which is when you can get back the substances you started the reaction with. A reversible change might change how a material looks or feels, but it doesn’t create new materials.
If you’d like to further discuss the chemistry behind the ice cream, create a second experiment by placing only the ice in a separate gallon sized bag. Create a small bag per instructions and place the smaller bag into the bigger bag. Follow the instructions and shake for five minutes, examining the smaller bag throughout. Discuss why this recipe did not create any ice cream compared to the first one.
Using different ingredients will create varying results. Use different types of salt and discuss the results.