You are testing which material keeps the drink warmer for longer in a freezer. You can use a polystyrene cup, plastic cup covered in wool, etc. Put them all in at the same time. Check the temp before and record. Check the temp after 10, 20 and 30 mins of each cup also and record. Compare the before an after temp of every cup using the equation (change in temp / original temp (×100)). Hopefully that helps.
