Wave–Particle Duality

Particle or Wave? The Dual Nature of Matter

Wave–particle duality:
Wave–particle duality
(Greek: Δυαδική φύση κύματος–σωματιδίου)

What does it mean? ΣIn Quantum Physics, a photon (light particle) — or even an electron — is not only a particle, nor only a wave. It is both at once, depending on how you observe it.

Famous Experiment: Το πείραμα των δύο σχισμών When you send individual photons toward a screen with two slits, they don’t act like particles forming two lines. Instead, they create an interference pattern — as if they were waves interfering with each other.

But if you observe which slit they go through, they suddenly behave like particles!

So: The way you observe affects what “is”.

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Echo from the Ancients

Heraclitus: “Everything flows; nothing stands still.” Matter in quantum reality behaves just like this: It isn’t either/or. It is both/and. The photon is a wave. It is a particle.