Eli5 Why can’t we “know” the speed and position of an electron simultaneously? Why can we only measure one of these properties at a time?

Question

This always confuses me and I’m not sure how it works. Please explain…

In: 252

Answer 1

Imagine you want to take a photo of a car in absolute darkness: like trying to take a “photo” of an electron is.

On realistic scales, you can use a flashlight to send photons to the car, so that the light bounces back to your camera.

Do the same for an electron, and you’ll quickly notice that the size ratio photon-electron is much larger than the size ratio photon-car.

Now, imagine you scale back up the electron to the size of a car, and follow the same scaling for the photon you send to the car for it to bounce back on your camera. To “scale”, throwing photons at an electron is the same as throwing cannonballs to a car. Those will bounce back towards your gigantic camera, but at the tradeoff of sending the car out god knows where.