Ice Cream

Instructions

  • In the small Ziploc bag, mix together the milk, vanilla and sugar. Squeeze excess air from the bag and zip tight.

  • Put the small bag inside the gallon size bag and fill the bag with ice, then sprinkle salt on top.

  • Let all the air escape and seal the bag.

  • Wrap the towel around it to keep your hands from getting cold in the process of shaking.

  • Shake the bag for about five minutes, making sure the ice surrounds the cream mixture.

  • Enjoy your homemade ice cream!

Materials

  • 1 sandwich size ziplock

  • 1 gallon size Ziplock

  • 4 cups of ice

  • 1/2 cup of salt (rock or course salt)

  • 1/2 cup half-and-half

  • 1 tbsp sugar

  • 1/4 tsp vanilla extract

  • Small towel

Questions:

  • How do the ingredients change during this process?

  • How important do you think it is that they are cooled to a certain temperature?

  • Would different types of salt change the outcome??

  • What other things could be added to the mixture?

What is happening?

Salt allows the ice and salt mixture to get colder than pure water ice. This extra-cold mixture is able to freeze the ingredients in the bag and turn them into ice cream. While pure water freezes at 0 degrees Celsius (32 degrees Fahrenheit), water mixed with salt will freeze below 0 degrees Celsius.

In creating your ice cream you also made an emulsion. Emulsions are the combination of two liquids that normally do not mix well like fats and water. In your ice cream, the fat molecules in the cream are perfectly mixed with water, ice crystals, sugar, and small pockets of air to form a delicious cold treat.