First place at least 20 ice-cubes in a large freezer bag.

Next you will need a small freezer bag: place milk and/or cream, vanilla extract and sugar in this bag. squeeze the air out and seal the bag.

Place this small bag into another small bag, squeeze the air out and seal the bag.

Now the science part: add salt to your ice to lower the temperature to below zero. That's why we wore gloves, to protect our hands.

Now place the small bags in the large bag, seal the large bag and jiggle everything for about 10 minutes.

We are moving so fast it's blurry!

After 10 minutes, see if you have ice cream.

You can now eat your ice cream (as long as your bags haven't leaked and the salt hasn't got in!