How do we know that light is a wave

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In summary, the conversation discusses the development of the wave theory of light and its limitations in explaining certain phenomena such as the photoelectric effect and black body radiation. The wave theory originated in the 1600s and was first noticed to have wavelike properties around 1800, as predicted by the initial theory. The debate over the nature of light (wave vs. particle) can be traced back to Newton and Huygens, who were contemporaries. The conversation also mentions Thomas Young and his double slit experiment, which supported the wave theory and ended Newton's corpuscular theory of light. Finally, the conversation touches on Maxwell's equations and how they support the idea of light as a propagating wave.
  • #1
cnidocyte
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I'm reading a bit about atomic theory at the moment and I keep reading about how the wave model of light is not sufficient to explain things like the photoelectric effect and black body radiation, which is where quantum theory stepped in but I haven't seen any mention of where the wave theory came from.
 
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  • #2
Here's the guy who started it all - a good place to start

http://en.wikipedia.org/wiki/Christiaan_Huygens"
 
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  • #3
Light was first noticed to have wavelike properties such as poliarization and diffraction around 1800 as predicted by the initial wave theory which originated in the 1600s: http://en.wikipedia.org/wiki/Light#Wave_theory
 
  • #4
russ_watters said:
Light was first noticed to have wavelike properties such as poliarization and diffraction around 1800 as predicted by the initial wave theory which originated in the 1600s: http://en.wikipedia.org/wiki/Light#Wave_theory

Ah right I didn't even think about diffraction thanks.
 
  • #5
Because it has a property that belongs to a class we call wave.
 
  • #6
Newton was an advocate of light as a particle (they were called corpuscles back then, I believe). Newton and Huygens were contemporaries and knew of each other's work. So the debate over the nature of light (wave vs. particle) goes way back...

I think it is usually credited to Thomas Young and the double slit expirement that put an end to Newton's corpuscular theory of light. Until Einstein and his explanation the photoelectric effect -- for which he received the Nobel Prize.
 
  • #7
it also follows from maxwells equations. a solution to these is a propagating wave for electric and magnetic field
 

1. How was it first discovered that light is a wave?

Light was first discovered to have wave-like properties by English scientist Thomas Young in the early 1800s. He performed a famous experiment called the double-slit experiment, which showed that light could interfere with itself, similar to how waves behave.

2. What evidence supports the idea that light is a wave?

There is a significant amount of evidence that supports the idea that light is a wave. One of the most compelling pieces of evidence is the phenomenon of diffraction, which shows that light can bend and spread out when passing through small openings or around objects, just like waves do. Additionally, the polarization of light, its ability to exhibit interference, and its interaction with other waves all provide evidence for its wave-like behavior.

3. Can light also behave like a particle?

Yes, light can also behave like a particle, which is known as the wave-particle duality of light. This means that light can exhibit properties of both a wave and a particle, depending on the experiment or observation being performed. This was first discovered by Albert Einstein in the early 1900s and is now a fundamental concept in quantum mechanics.

4. How does the wave nature of light explain its speed and propagation?

The wave nature of light explains its speed and propagation by demonstrating that light travels through space as an electromagnetic wave. This means that it can travel through a vacuum at the speed of light, which is approximately 299,792,458 meters per second. The wave nature also explains how light can interact with matter, as it can transfer energy and momentum to particles it encounters.

5. Are there any real-world applications of knowing that light is a wave?

Yes, the understanding that light is a wave has led to many real-world applications. These include technologies such as fiber optics, lasers, and holography. It has also allowed for the development of many medical and scientific instruments, such as microscopes, telescopes, and spectrometers, which all rely on the wave-like behavior of light to function.

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