An all-time favourite science experiment you can try safely at home, ice cream in a bag is a delicious and fun way to get scientific this school holidays!
What You’ll Need (per serving):
- 1 tablespoon of sugar
- 1 cup of whole milk
- 1 teaspoon of vanilla essence
- 6 tablespoons of rock salt or table salt
- 2 cups of ice
- 1 x 4 litre zip lock bag
- 1 x 1 litre zip lock bag
Method:
Step 1
Half fill the 4 litre zip lock bag with ice (about 2 cups).
Step 2
Add the salt to the 4 litre zip lock bag and seal again.
Step 3
Pour in the sugar, milk and vanilla essence into the 1 litre zip lock bag and seal securely.
Step 4
Open the large 4 litre zip lock bag and place the sealed 1 litre zip lock bag inside. Seal the large bag again.
Step 5
Shake and rock the 4 litre bag of ice and salt consistently for 10 to 15 minutes. Wear an oven mitt or wrap a tea towel around the bag to protect your hands from the cold.
Step 6
After shaking, the mixture in the small bag will form into ice cream and is ready to eat! Enjoy with all your favourite toppings.
Why is salt added to the ice to help form ice cream?
When salt is added to ice it lowers the freezing point, increasing the speed in which the ice cream mixture is frozen into ice cream. By adding salt to the ice it then takes more energy to be absorbed from the surrounding environment, and for the ice to melt.