Remind your middle school scientists how fox ear size varies depending on the climate they live in; large ears allow heat loss while small ears keep heat in. Discuss how a cold-blooded animal might try to regulate body temperature. Then split the class into pairs and have them record temperatures at different locations around campus. They relate their temperature readings to where ectothermic animals might hang out. Finally, they relate what they've learned to the placement of solar panels on a building.