This is a test of commonsense. Complete the next sentence:

How to make flash freeze liquid
Gather your materials.
This substitute is made by combining dry ice and ethanol. For our purposes we will use 99% isopropyl alcohol or rubbing alcohol.
You will also need a plastic 2-liter bottle, a plastic 18 oz bottle, dry ice, and scissors. Dry ice pellets are easier to use than a block of dry ice.