Homemade Ice Cream

My favorite type of science is science that is fun and tasty! This homemade ice cream in a bag is one of my favorite experiments. It only requires a few household ingredients, so it is a great way to make dessert during this food shortage.

What you will need (makes one serving):

• 1/2 cup half and half
• 1 tbs sugar
• 1/4 tsp vanilla
• 2 quart plastic bags
• 1 gallon plastic bag
• 1/2 cup salt (preferably rock salt)
• 5 cups ice

Steps:

• Pour sugar, vanilla, and half and half into a quart sized plastic bag

• Squeeze the air out of the bag and seal it

• Place the plastic bag into the other quart sized plastic bag

• Add the ice and rock salt to the gallon plastic bag

• Place the sealed quart plastic bag into the gallon plastic bag and seal it

• Shake the bags for 5-10 minutes until you get an ice-cream-like consistency (you may need to add an extra cup of ice to the gallon plastic bag if its ice melts too quickly)

• Pour the ice cream into a bowl and add toppings

• Enjoy your tasty treat!

What’s the science behind this experiment?

The salt added to the ice lowers the melting point of the ice, just like when we
add salt to roads when it snows. In order for the ice to melt, however, it has to absorb heat from it’s surroundings like the ice cream in the bag. The ice pulls the heat away from the ice cream which allows the ice cream to freeze.

To freeze, the ice cream has to change states of matter. At first, the mixed cream, vanilla, and sugar was a liquid, but as heat was removed, it turned into a solid state.

Ice cream is also a compound. Once all the ingredients of the ice cream are mixed
together, they cannot be separated by physical means. For example, a salad is a mixture, so you could separate out the lettuce, tomatoes, and cucumbers in a salad; however, once you make your ice cream, you cannot separate the cream and the sugar. To separate the ingredients in a compound there would have to be another chemical reaction.