Seems like a simple way to control this would be have 4 containers of water. Container 1A - Control temperature Container 1B - Control temperature Both go in

Seems like a simple way to control this would be have 4 containers of water. Container 1A - Control temperature Container 1B - Control temperature Both go into freezer 1 Container 2A - Control temperature Container 2B - Near boiling Both go into freezer 2 Now see if there's a difference in freezing time for Container 1A compared to 2A.