Whatever happened to the Particle Theory of Light?

In summary, the book discusses the theory of light and how it is made up of particles. It also discusses reflection, refraction, and rectilinear propagation.
  • #1
Mark
58
1
Hello, I am a student in high schoool, and everywhere i look i see the obvious implications that light travels as a wave. I mean

-Rectilinear Propogation
-Refraction
-Reflection
-Diffraction

etc. all seem to point to wave theory, but what do the particle people say about these things..

just looking for a second opinion,

thanks
 
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  • #2
Mark said:
Hello, I am a student in high schoool, and everywhere i look i see the obvious implications that light travels as a wave. I mean

-Rectilinear Propogation
-Refraction
-Reflection
-Diffraction

etc. all seem to point to wave theory, but what do the particle people say about these things..

just looking for a second opinion,

thanks
Reflection and refraction are particle phenomena. The particle model is very much alive and well - in its domain of applicability: light is now well accepted to have a wave/particle duality.
 
  • #3
You could do worse than read a book called "QED:The Strange Theory of Light and Matter" by Richard P. Feynman. He takes on versions of all these phenomena, analyzing with a conceptual setup consisting of a laser source, a block of glass and a photomultiplier as a counter. He considers reflection off the glass block in two stages: first, assuming for simplicity that the reflection all takes place off the surface of the glass; second, the reflection is layered throughout the glass. He constructs a diffraction grating by painting out certain positions along the surface of the glass. He handles refraction by considering the detector embedded in the glass (a bit of a far-fetch!). Rectilinear propagation is the most interesting thing of all. He denies that light particles are constrained to move along straight lines, then he shows how neighboring non-rectilinear paths effectively cancel each other, making the straight paths the only real contribution of the light energy at the end.

The one light phenomenon he apologizes about not covering is "polarization". It is a complicating factor for the rest of his presentation, so he elected to omit it.

I would have groused some about calling it a "particle" theory, but Feynman says it is in his first chapter. "We know that light is made of particles because we can take a very sensitive instrument that makes clicks when light shines on it, and if the light gets dimmer, the clicks remain just as loud-there are just fewer of them."

It might take multiple readings to get through this book, but it is worth it. Check out the drawings and their captions for a quick take on what is going on.

The theory of light is done in the first two chapters of QED. The rest of the book talks about electron/light interactions and quark/gluon interactions, so it is not strictly only about QED (Quantum Electrodynamics).

Amazon link to this book --->
 
  • #4
I found the following this AM

Feynman QED lectures on video --->
http://www.vega.org.uk/series/lectures/feynman/ [Broken]
 
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1. What is the Particle Theory of Light?

The Particle Theory of Light, also known as the Corpuscular Theory of Light, is a scientific theory that states that light is made up of tiny particles, or corpuscles, that travel in straight lines and interact with matter to produce the sensation of light.

2. Why was the Particle Theory of Light proposed?

The Particle Theory of Light was proposed in the 17th century by scientists such as Isaac Newton and Christiaan Huygens in an attempt to explain the behavior of light. At the time, it was believed that light traveled in straight lines, but the wave theory of light had not yet been developed.

3. What evidence supported the Particle Theory of Light?

One of the main pieces of evidence supporting the Particle Theory of Light was the wave-particle duality of light. This phenomenon, observed in experiments such as the double-slit experiment, showed that light can behave as both a wave and a particle. Additionally, the Particle Theory of Light was able to explain the reflection and refraction of light.

4. Why did the Particle Theory of Light fall out of favor?

The Particle Theory of Light was eventually replaced by the wave theory of light, which was able to better explain certain phenomena such as interference and diffraction. Additionally, advancements in technology, such as the discovery of the electromagnetic spectrum, provided evidence that light behaves as a wave.

5. Is the Particle Theory of Light still relevant today?

While the Particle Theory of Light is no longer the predominant theory of light, it still holds some relevance in modern science. The concept of particles of light, known as photons, is still used in various fields, such as quantum mechanics and astronomy. However, the wave theory of light is now the accepted explanation for the behavior of light.

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