Heisenberg's Uncertainty Principle (what it really means)

The uncertainty principle is not just about measuring. It's about how much information you can have about something at any instant, and it comes from the fact that everything has both particle and wave properties.

0:00 - Intro
1:30 - Uncertainty & measurement
3:12 - Physical meaning of wavelength
4:25 - How can something be both particle & wave?
5:39 - Wave packets
7:01 - Uncertainty & single slit interference
8:10 - Uncertainty in energy & time

The uncertainty principle for position and momentum is all that is usually covered in an intro physics class, but there are more pairs of variables that follow it: energy & time and magnitude of angular momentum & direction of angular momentum are two other conjugate pairs.

[jcpmac]

It's the little, but all-important and so often neglected details of the subject being given attention in this video that really help make it all so understandable. You often see representations of the wave packet in other videos, to take just one example, but what is or how it relates to wavelengths is seldom made clear. Here, though, it's perfectly spelled out. There's even a realworld demonstration of the results of a single-slit experiment! This is what an educational video should be.

[spinkets]

HI, nice vid. but a clarification is needed. @7:50 you have the Delta_Px only covering one blob, what about all the other blobs both above and below this main blob. THEIR deviations from the original direction of the photon are much greater, surely all of those photons have much greater delta_Px than merely just the span of one single blob. the blobs span the entire vertical height of your youtube video frame!
That's a lot bigger a delta_Px than what you indicate.

[gogonogo]

This blew my mind!! I knew about the uncertainty principle and the casimir effect but I had no idea they were directly related! I am fulfilled