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

Speed is what happens between two points.

When people say “your car was driving 50 km/h at this point on the road” what they mean is that while passing from a point before the spot you were measuring at, to a point behind the spot you were measuring at, you moved with a speed of 50 km/h.

There is no speed in one single point; you’re at that point, nowhere else, otherwise you couldn’t have been seen there. Speed is how fast you arrived and left at the point that was being measured.