eli5 what does it mean for a particle to be a “wave”?

Question

most people give an example of water waves but I thought every single “wave” has particle-like atomic structure. What does it mean for the most smallest particle like an electron to be a wave?

In: Physics

Answer 1

First, explain Young’s Double Slit Experiment to a five-year-old, demonstrating wave-like characteristics of coherent light.

[https://courses.lumenlearning.com/suny-physics/chapter/27-3-youngs-double-slit-experiment/](https://courses.lumenlearning.com/suny-physics/chapter/27-3-youngs-double-slit-experiment/)

Then, explain Einstein’s Photoelectric Effect to a five-year-old, proving individual electrons travel as discrete particles.

Then, perform Young’s Double Slit Experiment together with individual electrons traveling as particles collected from Einstein’s Photoelectric Effect experiment, then passing though a double slit, collecting and locating the electrons on a collection plane behind the double slits.

Those individual electrons, traveling as particles, show up at the collection points behind the double slits as if they’re traveling as waves through the double slits, then hit specific points on the collector as particles. The pattern on the collection points, diffused in one direction by the narrow slits, has periodic spots where electrons frequently hit (bright) and never hit (dark) corresponding to the wavelength of the electron as calculated by the energy of the electron.

Cover one of the double slits, and the pattern changes so the bright and dark spots disappear, becoming only a wide smear caused by diffusion due to the narrow slit.

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Take Young’s experiment and dim the light so much that the light is traveling as identifiably separate photons, and you’ll still find the “bright” and “dark” points on the collection plane. Similarly, covering one of the double slits changes the pattern to the wide smear caused by diffusion of light through the narrow slit.

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Both the diffusion of these particles (photons or electrons) from passing through the narrow slits and the interference pattern created by the double narrow slits are evidence both photons (light packet) and electrons acting as waves.