Light Explained: Photons, EM Radiation & Frequencies

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Discussion Overview

The discussion revolves around the nature of light, photons, and electromagnetic (EM) radiation. Participants explore the relationship between light as a form of EM radiation, the characteristics of photons, and the classification of different frequencies of EM radiation. The conversation touches on theoretical concepts and definitions within physics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether photons are simply one type of particle among many and if they only appear when EM radiation is created.
  • Another participant asserts that light exhibits wave-particle duality and that all types of EM radiation, including radio waves and x-rays, can be classified as light based on their wavelengths.
  • A participant asks if sound can be considered a form of light, which is countered by others who clarify that sound is a longitudinal wave and travels through a medium, unlike light.
  • There is a discussion about whether photons are special types of particles, with one participant suggesting they are significant as carriers of the electromagnetic force but acknowledging the existence of many other particles.
  • Another participant reflects on the interconnectedness of electromagnetic radiation with other fundamental components of the universe, suggesting that it may not be fruitful to rank them hierarchically.

Areas of Agreement / Disagreement

Participants express differing views on the classification of photons and their significance compared to other particles. There is no consensus on whether photons are unique or simply one type of particle among many, and the discussion remains unresolved regarding the philosophical implications of light's nature.

Contextual Notes

Participants reference the standard model of particle physics and the fundamental forces, noting that gravity's role is still debated. There are also unresolved questions about the definitions and classifications of light and EM radiation.

geordief
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Sorry to be so ignorant!
I have heard that light is a type of electro-magnetic radiation but I was also under the apprehension that photons were particles of light.
Is that latter assertion too loose?

Are photons just one of the many kinds of particles and do they just show up when electro- magnetic radiation is created ?

Also ,if there are different frequencies of EM radiation can they all be classed as some form of light? Or are they just some class of EM radiation?
 
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Light acts as a particle AND as a wave. This behavior is known as wave-particle duality. Any type of electro-magnetic radiation is a light, including radio waves, x-rays, infrared etc.
It's simply different wavelength. What we see and call as visible light, is simply photons with wavelengths from 400nm to 800nm (i don't remember exact numbers).
 
thanks.
Is sound a form of light?
 
sound is a longitudinal wave - very different indeed.
 
No, sound travels in medium such as air. It doesn't travel at the speed of light. You can see a lightning first, and sound later. The speed of sound is determined by the medium, in air it's somewhere around 300m/s.
 
thanks.
That was a major misapprehension on my part!
But what about the other part of my question?

Are photons special types of particles or just one amongst many? Are they even primus inter pares (first among equals).

In my mind light seems primordial but is it really so? (I don't want to sound like I am making a philosophical point)
 
Electromagnetic radiation is just one of the components of our Universe. It can be a bit fruitless to try to put EM in some sort of hierarchy, along with matter, gravity, space and time. They are all part of the same structure. Change something about one of them and all the others would change too. It would be a different Universe.
One of the aims of Science is to link them up in a 'theory of everything' (TOE).
 
geordief said:
thanks.
Are photons special types of particles or just one amongst many? Are they even primus inter pares (first among equals).

In the standard model of particle physics there are three fundamental forces: Strong Nuclear Interaction, Weak Nuclear Interaction, and Electromagnetism. Each of these forces has a given force carrying particle. The Gluon for the strong interaction, the W± and Z bosons for the weak interaction, and the Photon for the electromagnetic force. So yes, it can be considered special in the sense that it is a carrier of a major force but there are countless other particles that have been discovered or hypothesized.

For reference:
http://en.wikipedia.org/wiki/Standard_Model
http://en.wikipedia.org/wiki/List_of_particles

**Gravity is considered a fundamental force but the cause of gravity is still debated, which is why it is not mentioned in the standard model.
 

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