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Wave-Particle Duality & The Double Slit Experiment

waves water raindrops Rick Sturch
Raindrops in water, with waves emanating outwards. Shot at 1/200 shutter speed, f5.6

In one of my earlier posts, I made an argument that if a tree falls in the forest, and there wasn't an auditory nervous system to hear the noise it makes, it doesn't make a sound.

All information, it seems, that travels about in the external world travels as a wave. Light, sound, heat - even gravitational force travels in waves. Furthermore, those waves can never travel faster than the speed of light. That is something to think about.

If the sun were to somehow disappear instantaneously, we here on Earth would not know for about eight minutes (that's how long it takes light to travel from the surface of the sun to the Earth). The reason? Because both light and gravity travel at the speed of light. For all you know, the sun has already disappeared.

Matter, in addition to light, seems to behave as both a wave and a particle. If you're not sure what I mean, let me use an example.

The double slit experiment highlights just how weird this is. Imagine you were in a dark room, and you shone a flashlight at a board you've positioned in-between the light and the wall.

If you have only cut one slit on the board, all the light will go through the one slit, and there will be one line on the wall behind. This makes sense. When you add a second slit, though, things change. This is because the light or matter is travelling through both slits at the same time.

There will be an interference pattern on the wall behind the slits, and this happens both with light, and matter (electrons, for example).

The weirdest part is that when you add an observer at the slits, and basically force the light/matter to decide on a position when going through the board, and the interference pattern changes. That's weird.

It makes you wonder, when a tree falls in the forest, and there's nobody around to hear it, does the tree really fall over? Perhaps the probability wave has not yet collapsed.

Search for Schrödinger's cat if this intrigues you.

By Rick Sturch

Like this post? Check out some of my other blog posts here or here.


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