This exhibit in the Exploratorium in San Francisco is probably the coolest (hottest?) I've ever seen. Or the most surprising at least. It's one that made me stop and think. One that actually surprised me. The exhibit allows you to visualize infrared waves.
As you know, infrared waves are electromagnetic waves (light) emitted by things we on earth consider "hot." Like hot people. But since I'm talking about temperature, even homely people emit infrared waves. In physics, everybody is hot.
When you see people, typically you're seeing the visible light that has reflected off of them. But people also emit light - in infrared wavelengths. The "Heat Camera" in the Exploratorium lets you "see" this light. Its camera records infrared waves we can't see a displays them in colors we can. Areas that are colder are darker - because they emit fewer infrared waves - and areas that are hotter appear brighter due to the opposite effect.
So what happens when you put your hand on a cold metal star and let the metal suck the heat out of your hand?
The star actually appears on your hand in the infrared display!
This shows you that cold things suck the heat away from your body in very localized regions. So localized that you can still see the points of the star on your hand.
Check out the exhibit at the Exploratorium to answer questions like:
Do mirrors reflect infrared light? Is there anything that will reflect in infrared?