Gravenstein 4th grade students designed and built thermoses with plastic bottles, newspaper and tape. Each class was competing for 1st place, the winner having the coldest thermos. “The Freezer” won, having the largest ice cube after 75 minutes at .3g.

I’ve done a similar competition with high school students, who designed and built houses out of cardboard. We placed a temperature sensor/logger inside them on a hot day, and the coolest house won.

Each ice cube was .5 grams.