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Wave-particle duality doesn't mean that light is sometimes a wave and sometimes a particle, it means it's a third thing that has some things in common with both waves and particles

When we're measuring light passing through diffraction grating, it's most useful to treat it like a wave. When we're discussing the photoelectric effect it's best to treat it like a particle.

A good analogy I read in a reddit comment that I can no longer find: wave-particle duality as a concept is like if you saw a train and described it as exhibiting "horse-house duality", because it's sometimes like a horse in that it moves around and takes you to places, and sometimes like a house in that you can sit inside and it protects you from the elements. But you know it isn't a horse or a house, it's a third thing. If you're solving a question about how long it takes to travel somewhere you might model the train as being like a horse. If you're solving a question about how much stuff can fit inside of it, you might model it like a house. But you know neither of those are actually the truth.

All particles have wave-like properties. But for particles of fairly high mass, those wave-like properties are so small that it's easier to ignore them.

Every object can act as an particle or wave. The higher the particle (mass) the lower the waves get. Same way around.

Probably light has the perfect balance between particle and wave so it can be shown as both. (I’m not a scientist, just looked it up real quick.)

….. It depends on how you experiment with light. You can experiment with an solution that says light acts as particle or get experiments that say light acts a wave. Don’t really know how to explain in detail in the English language as a non-native.

If you can break down the explanation of the link below maybe you can help your student find an answer.

https://theconversation.com/curious-kids-is-light-a-wave-or-a-particle-162514

Energy can't be caught because it's not a physical thing. It's a measure of the amount of work something can do, how much impact on its surroundings something can have. And that something doesn't have to be matter. The energy of forces (their fields) can bend space-time to generate gravity just like mass does.

It's not a definition or anything, but I like to think of energy as the amount of "capacity to exist" in the universe.

As for the particle-wave duality... It's more a consequence of is thinking there IS a duality. Everything in the universe has "particle" properties like momentum or spin and everything can have wave behaviours like interference. Literally anything. Light has momentum. It can exert pressure. Even mechanical waves (sound) can have particle properties assigned to them (although they're called quasi-particles, because they're not real particles, like an electron). Particles can interfere.

In short, there's no such thing as a "pure" particle or wave, so there's not really any "duality". It's just that for certain interactions, particle-like properties are what we test for, while in others it's wavelike properties. But the point is that WE are selecting this.

It's like a cylinder. It can be a rectangle from one angle. It can be a circle from another. But it's not one OR the other. It's only the fault of how we choose to view it.

As others have said, light's behavior depends on the circumstances.

Demonstrating its wavy nature is very easy. All you need is some point light source (e. g. a dia projector with a piece of carboard with a small hole over the objective, a street lamp far away, &c. – do NOT use a laser, you don't want to shine that in an eye) and a piece of aluminium foil with a pinhole in it. Looking at the first through the second you'll see an Airy disk with some rings around it.

It gets mind-blowing if you make a second pinhole in the foil, as near as possible to the first one. Can you guess the result? Spoiler: >!You'll still see the disk and rings, but now with dark interference bands over them.!<

But exhibiting light's particle behavior is difficult and would need a physics lab. You can look up Einstein's 1905 Nobel prize for the photoelectric effect, it's about that.

The next best thing would perhaps be a cloud chamber video?

So the somewhat unsatisfying answer, as we crave clear-cut ones, is that a quantum is neither a particle nor a wave but… a quantum, even if it can behave like the one or the other, depending on the question asked (the experimental setup).

Somebody gave a metaphor for that. Take a cylinder. Seen from one direction it looks like a disk. From another, like a rectangle. Yet it is neither.

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Light travels as a wave but interacts as a particle.

Another aspect is wavelength which affects frequency, or how many wavelengths of light will pass a certain point per second. The shorter the wavelength, the more can pass that point in a given time, so the more energetic the light. Light does oscillate, and the rate at which it oscillates might be related to the frequency.

That's enough info to start your student browsing a rabbit hole of science. knowledge in internet searches. YouTube is good for the visuals and science explainers like Arvin Ash and Science Asylum

If your student is interested in the quantum model, the light doesn't exist (in the form we know) until interacted with. Whatever the unformed photon is before it becomes a photon, imagine it as an expanding sphere that's a collection of possible locations where each photon could interact, the expanding at the speed of light, and when the photon emerges to interact then all the other possibilities vanish instantly (faster than the speed of light).