What did you learn today?

[woodsmoke]

That is very good Halationeffect, I'll use it next semester!

thanks

woodsmoke

[kubicle]

@woodsmoke:
I know you were trying to simplify the idea and give real world examples, but trying to simplify quantum mechanical concepts often gives the reader a wrong impression.

Your examples basically describe that it is hard to take 100% accurate measurings, and that's not what the uncertainty principle is about.

For example, in your cat scenario, it would theoretically be possible to calculate the times of light travel and human nervous system response (and one could eliminate the human factor completely with measuring equipment). The uncertainty principle is not about what kind of measuring possibilities we have at our disposal, it's about what can theoretically be known (not what's practically possible).

Sticking with your cat example, it we try to measure the position and momentum of the cat by sending a photon to it, we can get it's position pin-pointed in the accuracy of the wave-length of the photon. However the photon gives a very gentle push to the cat affecting it's momentum. If we wish to measure the position of the cat more accurately, we have to decrease the wave-length of the photon, for which we need a more energetic photon that gives a slightly heavier push etc. On the other hand, if we increase the wawe-length, we'll get the momentum more accurately, but the accuracy of the position decreases.

(one can imagine that a single photon doesn't really push a cat all that much, no matter how energetic a photon that is, that is why the effects of the uncertainty principle is negligible on macroscopic objects...like cats...it's like changing earth's orbit with a golf ball. However, a single photon can have a sigificant effect on an electron, for example.)

[benny_fletch]

I learned that packing everything you own to move blows (the PC version )!