So, if we take fire, how come not all of the energy is released as light, why is some of it released as heat as well as light?
In: Physics
None of the radiation is heat. Radiation is a way of transferring heat; the radiation itself is not heat. When radiation is absorbed by an object it causes the object to heat up.
Some radiation you can see, called visible light. Some radiation you can’t see, like infra-red and ultra-violet, but both of those will still carry heat. The mix of radiation given off by an object is mostly set by the temperature of the object.
Radiation/light is a spectrum, and all that differs is wavelength and frequency. It ranges from gamma rays that have a high frequency, small wavelength to radio waves which have a long wavelength, low frequency. Visible light is somewhere in the middle which we can see. Infrared light is slightly lower frequency than visible light, so we can’t see it but we can feel it as heat. This is how those night vision goggles in movies work. The reason some energy from a fire is heat and some is visible is because energy is released from electrons in certain discrete packets of energy based on which elements are burning/how hot. That’s why some fires are red but hotter fires are blue. That’s also why fires don’t emit a lot of UV rays that sunburn you, but the sun, which burns waaay hotter, does. All this I learned in college physics and find it really interesting
Energy is all the same.
You may think of light, Heat, radiation and sound being four different things but it is the same thing… “energy” at different frequency’s.
When you burn a campfire the different fuels and parts of the fire radiate different wavelengths of energy, some you recognizes as heat ,some you recognize as light , some you recognize as a popping & cracking sound.
Radiated heat IS light. It’s just a big broad span of different wavelength that your eye can’t sense, but heat nerves on your skin can
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