How do molecules radiate photons and contribute to thermal radiation?

In summary, when a substance gains energy, its molecules vibrate faster and increase in temperature. If heat is lost through means other than radiation, the molecules do not emit photons. The source of these photons is the changing electromagnetic fields within the heated material, which are caused by the random movement of charged particles. It cannot be narrowed down further to a specific source within the material.
  • #1
Zaya Bell
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If a substance gains energy, it's molecules vibrate faster and thus the material increases temperature. My question is if heat lost through any other means but radiation is zero, how exactly does these molecules radiate photons?
 
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  • #2
Zaya Bell said:
if heat lost through any other means but radiation is zero
If radation is zero, the molecules do not radiate photons, so the question
Zaya Bell said:
how exactly do these molecules radiate photons?
appears a bit strange. Can you elucidate ?
 
  • #3
BvU said:
If radation is zero, the molecules do not radiate photons, so the question
I'm saying that all other forms except radiation is zero.

BvU said:
appears a bit strange. Can you elucidate ?
It is said that all molecules above absolute zero emit thermal radiation which are actually photons. The question is, what is the source of the this photons? From the electron? nucleus? Where? And how?
 
  • #4
Google for black body and from there for black body radiation, Rayleigh-Jeans, Wien, Planck etc.
Zaya Bell said:
I'm saying that all other forms except radiation is zero.
Ah, I misread, sorry.
Zaya Bell said:
It is said that all molecules above absolute zero emit thermal radiation which are actually photons.
correct -- up to a point: individual molecules do not have a temperature. They have velocities and thereby kinetic energy. The temperature of a macroscopic quantity of material has a temperature that is directly related to the average kinetic energy.
The question is, what is the source of the this photons? From the electron? nucleus? Where? And how?
any phenomenon that can absorb energy (e.g. molecular vibrations, rotations, electron orbits) to go into a state of higher energy can emit energy and end up in a lower energy state.

[edited the 'correct'a little...
 
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  • #5
Zaya Bell said:
The question is, what is the source of the this photons? From the electron? nucleus? Where? And how?
The electromagnetic fields within the material are constantly changing because they are produced by the random movement of trillions of trillions of charged particles in the heated material. These changing fields are what causes the electromagnetic radiation.

So the source of the photons is the heated material, and it doesn't make sense to try to narrow it down further.
 
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  • #6
BvU said:
individual molecules do not have a temperature.
Yeah, sorry. Wanted to say all molecules in a material above absolute zero.
 
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Related to How do molecules radiate photons and contribute to thermal radiation?

1. What is thermal radiation's origin?

Thermal radiation is a type of electromagnetic radiation that is emitted by all objects with a temperature above absolute zero. It is caused by the movement of particles within the object, which results in the emission of photons.

2. How is thermal radiation different from other types of radiation?

Thermal radiation is unique in that it is emitted solely due to an object's temperature, rather than its chemical composition or atomic structure. It is also the only type of radiation that can be emitted or absorbed by all objects, regardless of their composition.

3. What factors affect the amount of thermal radiation emitted by an object?

The amount of thermal radiation emitted by an object is dependent on its temperature, surface area, and emissivity. Objects with higher temperatures, larger surface areas, and higher emissivity will emit more thermal radiation.

4. Can thermal radiation be controlled or manipulated?

Yes, thermal radiation can be controlled and manipulated through various methods. For example, the temperature of an object can be controlled to change the amount of thermal radiation emitted, and materials with different emissivity values can be used to alter the amount and type of thermal radiation emitted.

5. How is thermal radiation used in everyday life?

Thermal radiation has many practical applications in everyday life. It is used in heating and cooling systems, cooking, and various industrial processes. It is also an important factor in the Earth's climate and plays a role in the greenhouse effect.

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