How can a fire warm you without touching you?
A fire emits electromagnetic radiation that your skin can absorb. This transfers energy across the space between you and the fire without requiring hot air to carry it.
- The scientific idea
- Thermal radiation
- Fields of science
- Physics
How it works
Standing beside a fire, you can feel warmth on the side facing it. Some energy reaches you as radiation and is absorbed by your skin. It does not need a stream of hot air to make the journey; radiation can cross a vacuum.
Look closer
Visible glowing is only part of the story. Objects at everyday temperatures, including people, emit radiation mainly in the infrared, beyond human vision. They also absorb radiation from their surroundings. Warming or cooling depends on the balance of those exchanges. The room does not stop exchanging radiation when its lights go out: darkness describes what your eyes detect, not the absence of electromagnetic energy.