Museum of Science and Industry

Make Ice Cream


Step 1 of 6:

Here's the Materials You'll Need:

Ice
Salt
Milk, cream or half and half
Sugar
Vanilla
Other flavors, such as chocolate syrup(optional)
Gallon-sized re-sealable plastic bag
Pint-sized re-sealable plastic bag
Measuring cups
Measuring spoons


Step 2 of 6:

Fill the gallon-sized plastic bag halfway with ice. Measure 6 tablespoons of salt and add to the bag of ice. Shake the bag gently to mix it up.


Step 3 of 6:

Combine ½ cup of milk, 1 tablespoon of sugar and ¼ teaspoon of vanilla in a measuring cup. Stir to mix. Carefully pour the ice cream mix into the smaller bag.


Step 4 of 6:

Seal the smaller bag so it closes tightly, getting as much air out as possible. Put the smaller bag inside the bag of ice, and seal the larger bag.


Step 5 of 6:

Shake, shake, shake the bag for at least 5 minutes. Wrap it in a towel when it gets too cold to handle. When the ice cream is frozen, open the bags and enjoy your treat!

Try this – Try different recipes by adding flavors to your ice cream mix, such as fruit juices or chocolate syrup. Break some candy or nuts into small pieces and add them if you’d like. Try making different combinations and see which ones taste best.


Step 6 of 6:

Water freezes and ice melts at a temperature of 32 degrees Fahrenheit (0 degrees Celsius).  Salt lowers the freezing point of water to -22º F (-30º C). That’s why we put salt on icy sidewalks and roads in the winter – the salt encourages the melting process.

When you added salt to your bag of ice, the temperature dropped below 32ºF and stopped around 14ºF (-10 C). To keep melting the ice, more heat is needed. When you put your bag of ice cream mix into the bag of melting ice, heat from the ice cream bag flowed into the ice and salt water. That made the ice continue to melt, and it made the ice cream mix get colder. Eventually, the water and ice cream mix started to freeze. And what did you get? Ice cream!


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