you CAN know both speed and location of a particle.?

Question

Throw a single photon at a wall. Where it hits is its location at that exact moment. We also know that light travels at c (about 300k km/s). Therefore, we know both the speed and location of that photon.

Jack : Wipe off the lube 1st. :-)

gebobs : details or it didnt happen

gebob : what I mean is, refute my logic.

gebobs :

"
You say yourself, "light travels at c (about 300k km/s)". How will you measure that? While we know that the speed in a vacuum may be constant, measuring that speed exactly could be more than a bit troublesome."

I dont understand this part.

I thought c was, in a vacuum, always the same exact number of m/s no matter how you looked at it. If you know a quantity, like my age, you dont need to measure it as its a given.

I feel my logic is flawed, see the comment about Einstein not being able to refute the uncertianty principle, but Ill be damned if I can google up a good clean argument to show me where I err.

mojorisin :

"How will you measure where it hits the wall? "

There are setups sensitive enough to trigger from the impact of one photon. You eye has millions of them. I know this hardware exists in a lab as well, they use it in the double slit experiment.

The world is a very strange place, even w/o quantum mechanics lol.

gebobs :

"Your simple experiment above sounds good on paper but it would not work. Please feel free to try though"

OK. I shined a laser at my wall. I can tell you the location of photons when they hit the wall, and their velocity.

Answer 1

I having some trouble getting the photon to stay in my hand.

Edit:
I just wiped off the lube and it still won't stay in my hand.

Edit2:
You idiot! You call that throwing a photon!!!

Answer 2

Nope. It is impossible to have a particle that has an arbitrarily well-defined position and momentum simultaneously and this uncertainty is defined by the Planck constant.

This is a mathematical ideal. Real experiments never even approach these limits of uncertainty.

Your simple experiment above sounds good on paper but it would not work. Please feel free to try though.

You say yourself, "light travels at c (about 300k km/s)". How will you measure that? While we know that the speed in a vacuum may be constant, measuring that speed exactly could be more than a bit troublesome.

Is that enough detail for you?

I like that you are looking skeptically at long-held scientific theories. It shows curiosity and that is the only way toward new knowledge.

Answer 3

How will you measure where it hits the wall? Have you ever seen a single photon? It is easy for me to understand your argument because it seems so strange to be told we cant know certain things more than an equation tells us we can. I had the same attitude when I started studying quantum mechanics last year. Honestly there is no logical, intuitive reason for this uncertainty. Take a course in quantum and youll realize the world is a very strange place.


P.S.
Quantumdude: uncertainty has nothing to do with wave particle duality or with the probabilistic nature of quantum mechanics... it is simply the result of taking the commutator of two operators. Nothing more.

Answer 4

It would be great if it was that easy, but it isn't. The uncertainty principle is a statement about the probabilistic nature of particles because of the wave particle duality, and cannot so easily be refuted. If Einstein couldn't completely refute it.....