Make you own tasty treat for a hot summer's day
This experiment lets you make ice cream in half the time it
would take in a freezer and it's scientific too!
What you need:
- 1/2 cup of milk (plain or flavoured)
- Ice cubes or a bag of ice
- 6 tablespoons of salt
- 1 tablespoon of caster sugar
- Small zip-lock bag
- Large zip-lock bag
- Tablespoon
- Gloves
- 1/2 teaspoon of vanilla essence (optional)
How to:
- Make sure all the equipment you use is clean.
- Mix the milk with the sugar in a small zip-lock bag. If you're
using plain milk you can add 1/2 teaspoon vanilla essence to make
vanilla ice cream. Seal the bag tightly.
- Fill the large zip-lock bag with ice and add the salt.
- Put the small zip-lock bag inside the large zip-lock bag. Make
sure both bags are sealed tightly.
- Put gloves on and squeeze and shake the bags. The longer you
squeeze the bag, the better the ice cream will be! It should take
about five minutes for the ice cream to set. Feel through the large
zip-lock bag to see if the ice cream is solid.
- Take the small zip-lock bag out and unseal it.
Grab a spoon and tuck in!
What's happening?
Salt lowers the freezing point of water - just like it does when
we put salt on icy roads in winter. The more salt added, the lower
the freezing point will be. This means that the temperature in the
ice bag can get as low as -5 degrees Celsius. This causes the ice
cream mixture in the bag inside the ice bag to freeze.