"Light is wave-like and particle-like" --- Why this is wrong?

In summary, the statement that light has both "wave-like" and "particle-like" properties is fundamentally out of sync with reality.
  • #1
DavidReishi
67
1
It's often said that light has both "wave-like" and "particle-like" properties, that light is both "wave-like" and "particle-like." But such a concept is fundamentally out of sync with reality. For, while it's true that light exhibits "particle-like" properties, the same cannot be said about "wave-like" properties. Real waves aren't "wave-like" any more than a real duck is a manifestation of being "duck-like." "Particle-like?" Yes, because photons have no rest mass. "Wave-like?" Uh, no, it's a real wave.

Conceptually, the more correct thing to say is that light has both particle-like and wave properties. Symmetry shouldn't be artificially inserted.
 
Physics news on Phys.org
  • #2
DavidReishi said:
Yes, because photons have no rest mass.
The description is not limited to light, everything can look "wave-like" and "particle-like".
DavidReishi said:
"Wave-like?" Uh, no, it's a real wave.
With a wave you cannot describe the photo-effect, for example.

All those things are attempts to describe quantum mechanics to a lay audience. They are not the actual physics, which deals with quantum objects in a purely quantummechanical way.
 
  • Like
Likes phoenix95
  • #3
mfb said:
The description is not limited to light, everything can look "wave-like" and "particle-like".

Okay, but I think you're missing the point. When evidence exists of light as a wave, e.g. the double-slit experiment, we're not talking about wave-like movement. We're talking about real wave movement. But when evidence exists of light "as a particle," the opposite is the case. We're not talking about a real particle, since real particles have rest mass. We're talking about particle-like attributes.

With a wave you cannot describe the photo-effect, for example.

And what? All that means is that light is in a particle-like form whenever it's being either emitted or absorbed by matter.

All those things are attempts to describe quantum mechanics to a lay audience. They are not the actual physics, which deals with quantum objects in a purely quantummechanical way.

Then physicists should change the way they attempt to explain the duality of light to lay audiences. Because to suggest that light has both "wave-like and particle-like" properties is inaccurate and misleading. It presents the problem as symmetrical, when it isn't. And in doing so it creates a problem where one doesn't exist.

Light is in a particle-like form when it's in contact with matter, and is a wave when it's in movement between particles of matter. What's so hard about that?
 
  • #4
DavidReishi said:
...and in doing so it creates a problem where one doesn't exist.

Light is in a particle-like form when it's in contact with matter, and is a wave when it's in movement between particles of matter. What's so hard about that?

You are supposing properties and attributes "that don't exist"... just "contact with matter" needs lots of attention.
Someone will come in shortly to mention that quantum entities don't have properties or attributes in the "usual" way.
 
  • #5
bahamagreen said:
... just "contact with matter" needs lots of attention.

Well we know that when light interacts with matter, it's either emitted from the matter or absorbed by the matter. So how 'bout this:

Light is in a particle-like form in its emission from matter, upon which it transforms into a wave in its movement from the matter, and back again into its particle-like form in its absorption back into matter.
 
  • #6
Perhaps it's best to say that quantum objects are neither waves nor particles.
They are quantum objects whose behaviour *resembles* classical waves or particles depending on the situation.
 
  • Like
Likes Merlin3189
  • #7
DavidReishi said:
Then physicists should change the way they attempt to explain the duality of light to lay audiences.

Good point.
 
  • #8
Human brains are good at using metaphor and simile too describe something that otherwise doesn't make sense. Or to fill in missing pieces of an observation. Don't know if that's a good thing or a bad thing. Maybe the quote, "You can't handle the truth!" from I-forget-the-movie explains this phenomenon. I've always wondered if other animals do this.
 
  • #9
rootone said:
Perhaps it's best to say that quantum objects are neither waves nor particles.
They are quantum objects whose behaviour *resembles* classical waves or particles depending on the situation.

I think you're falling into the trap of the false symmetry. While manifestations of light resemble classical waves, they never resemble classical particles...because classical particles have rest mass. When light is demonstrated to be in a wave-form, it's not a flawed wave-form. As far as we can tell, it's simply a wave-form as we know waves. But whenever light is demonstrated to be in a "particle-form," it is an inherently and fundamentally flawed particle-form because it has no rest mass.

The false symmetry expressed in your words is part of the reason why people in general, physicists included, overlook the simple solution to the "duality of the theory of light." Namely, that it's light itself that has the dual nature, not in some mysterious way, but simply in that light transforms from one form into the other. It commences its existence being emitted from matter in a particle-like form (a photon), then it transforms into a wave and moves, and then finally it is transformed again into the same particle-like-form (an identical photon to the first) as it is absorbed into matter. Upon which its existence is at an end.

(BTW, this simple solution to the problem of the dual theories of light is supported, so far, by the double-slit experiment, the photoelectric effect, low-light CCD experiments, and the fuzzy-shadow-edge effect of light.)
 
Last edited:
  • #10
Thread closed for Moderation...
 
  • #11
  • Like
Likes mfb, Orodruin and weirdoguy

Related to "Light is wave-like and particle-like" --- Why this is wrong?

1. What evidence supports the idea that light is both a wave and a particle?

The dual nature of light was first observed in the late 17th century by scientists such as Isaac Newton and Christiaan Huygens. Newton's experiments with prisms showed that light could be separated into different colors, indicating that light behaves like a wave. Huygens' theory of wave propagation also supported this idea. However, in the early 20th century, scientists like Max Planck and Albert Einstein showed that light also behaves like a particle, with properties such as energy and momentum. This was further confirmed by experiments such as the photoelectric effect and the double-slit experiment.

2. Isn't it contradictory for light to have both wave-like and particle-like properties?

At first glance, it may seem contradictory for light to have properties of both a wave and a particle. However, this is a fundamental aspect of quantum mechanics, which describes the behavior of particles on a subatomic level. In the quantum world, particles can exhibit wave-like behavior and vice versa. This is known as wave-particle duality, and it applies not only to light but also to all subatomic particles.

3. How can light be both a wave and a particle at the same time?

This is a difficult concept to grasp, but it is a fundamental principle of quantum mechanics. Essentially, light (and other particles) exist as a wave until they are observed or measured, at which point they behave like a particle. This is known as the wave function collapse. The exact mechanism behind this is still not fully understood, but it has been confirmed by numerous experiments.

4. Why do we still teach that light is both a wave and a particle if it seems so contradictory?

While it may seem contradictory, the dual nature of light has been repeatedly confirmed by experiments and is a fundamental aspect of quantum mechanics. It is the most accurate and comprehensive explanation we have for the behavior of subatomic particles. Despite its complexities, it has been successfully used to make predictions and advancements in various fields such as technology, medicine, and materials science.

5. Is there any way to definitively prove whether light is a wave or a particle?

No, there is no way to definitively prove whether light is a wave or a particle. As mentioned before, light exhibits properties of both, and its behavior can only be fully described using the concept of wave-particle duality. However, through careful experimentation and observation, scientists have been able to gather evidence that supports this theory and use it to make accurate predictions and advancements in various fields. In science, the most accepted explanation is the one that best fits the evidence, rather than being definitively proven or disproven.

Similar threads

  • Quantum Physics
2
Replies
36
Views
2K
Replies
4
Views
450
  • Quantum Physics
Replies
2
Views
1K
  • Quantum Physics
Replies
9
Views
1K
Replies
3
Views
838
  • Quantum Physics
Replies
17
Views
2K
Replies
3
Views
1K
Replies
17
Views
3K
  • Quantum Physics
Replies
3
Views
346
Back
Top