You can see temperature when you look at a thermal image like the Infrared Camera but humans are blind to this type of light unless the object is super-duper hot, like the sun, the flames of a campfire, a red-hot electric burner on the stove or the filament in an old-fashioned light bulb.

The picture above is what’s known as a Thermal Image or Infrared Image. Red shows the warm areas and blue indicates cold.

Firefighters use thermal imaging cameras to “look through” smoke and “see” the color of heat from flames. So, if a fire is burning between two walls or behind a closed door in the next room, firefighters know exactly where the danger is located. Thermal images can also detect where people are in a room so they can be rescued.

These principles can be seen using inexpensive thermal cammeras like those for FliR and Seek Themal. We use one from Seek Themal.