Homemade ice cream

How to make homemade ice cream

This fun science project ends with you eating the results – how great is that?

Make your own ice cream in a plastic bag with no freezer required. This project explores freezing point depression – where the freezing point of liquid is lowered by adding another component to it. For example, when salt is added to an icy road it mixes with a small amount of liquid water. This combination reduces the freezing point further and prevents the melting ice from re-freezing. If you mix salt and ice in a bag, the same process makes the ice colder, meaning it can be used to make ice cream as we’re going to do here!

Materials required

¼ cup of sugar
½ cup of milk
½ cup of whipping cream
2-3 cups of ice
¼ teaspoon vanilla essence
½ to ¾ cup of salt (rock or table will be fine)
Measuring cups and spoons
1 small zip-top freezer bag
1 larger zip-top freezer bag

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Student Suleyman demonstrates another fun science experiment ‘Making Oobleck’

Homemade Ice Cream


  1. Add the sugar, milk, whipping cream and vanilla essence to the small freezer bag. Seal it tightly.
  2. Put the ice into the larger freezer bag. Use the thermometer to measure and record the temperature of the ice in this bag.
  3. Add the salt to the bag of ice.
  4. Place the smaller freezer bag (still sealed) inside the larger freezer bag with the ice and salt. Now close the larger bag.
  5. Gently move the bag from side to side. Be careful – it will be super cold so wear gloves to protect your hands. You need to rock the bag gently like this for 10-15 minutes until you can see the ingredients in the smaller bag have solidified.
  6. Open the larger freezer bag and using your thermometer, test and record the temperature of the ice and salt mix like you did before.
  7. Remove the smaller bag, open it and see how you’ve made ice cream! Now for the exciting bit; grab a spoon and serve your ice cream into a bowl ready to eat!

What did you notice?

What happens to the ice as your ingredients start to freeze?

Was there a difference in temperature of the salt and ice mix before and after?

Try it again but is it the same result if you leave out the salt or swap it for something like sugar?

Maybe try swapping the milk for a different type of milk – what happens then?

Homemade Ice Cream