I’ve heard that electrons behave differently when observed, but how do you actually observe an electron?
In: Physics
To observe something you have to interact with it.
When you see with your eyes, that’s light bouncing off surfaces and then into your eyes.
But why do we see different colours? Because some light is absorbed by the surface. Some photons (particles of light) hit the molecules of the surface and excite them. That’s why light is absorbed. It’s a transfer of energy. The molecule gains energy. It’s state has changed.
Think of it like feedback. You only know something is there if you interact with it. You can only see something if light interacts with it. You can only feel something if you touch it.
When physicists talk about “observing” something, they’re talking about interacting with it. Because you can’t observe something without interacting with it.
Back to seeing stuff, how does that even work? Well, a photon hits the back of your eyeball. The photon hits a molecule in your eye and triggers an electrical response. The photon is absorbed, it no longer exists.
When you want to observe something on the quantum level, you have to be careful so that your method of observation doesn’t interfere with what your trying to see. For example, it’s no good trying to observe a sandcastle blindfolded with a shovel. You’ll destroy the sandcastle and not know what it looked like.
This is the ‘observer effect’
Electrons are tiny, and exist as a wave as well as a particle. Because of this, it’s properties are constrained by the **Heisenberg Uncertainty Principle**. This principle basically says that more accurately we know one property of the particle, the less accurately we know it’s pair. If we accurately know the position of the electron, then we have no idea what it’s momentum is.
So we can’t completely describe the particle.
The observer effect is more of a practical limitation, while the Heisenberg Uncertainty Principle is more of a fundamental limit.
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