mamibrkly Posted April 10, 2008 Posted April 10, 2008 what are some similarities and differences between measuring an object in the quantum world and measuring an object in the macroscopic world? Any input is appreciated
swansont Posted April 10, 2008 Posted April 10, 2008 In the quantum world there is a fundamental limit to precision from the Heisenberg uncertainty principle.
Phi for All Posted May 8, 2008 Posted May 8, 2008 Any input is appreciatedAny helpful input is appreciated. All the previously deleted posts from this thread have been moved to their own thread right here. They had too much speculative science to be deemed appropriate answers to mamibrkly's original question.
stingray78 Posted May 8, 2008 Posted May 8, 2008 The uncertainty principle. You can know the momentum of a particle or its position, but not both. Check about the Copenhaguen interpretation of quantum mechanichs!! or better check this: http://www.tubepolis.com/play.php?q=copenhaguen%20interpretation&title=Free%2BWill%3F%2BQuantum%2BMechanics%2BClarified%2B%28Part%2B1%29&id=o_2JeUegZd8&img=http%253A%252F%252Fi.ytimg.com%252Fvi%252Fo_2JeUegZd8%252Fdefault.jpg
Farsight Posted May 10, 2008 Posted May 10, 2008 what are some similarities and differences between measuring an object in the quantum world and measuring an object in the macroscopic world? Any input is appreciated Objects in the quantum world are "actions". This is why we have Planck's constant. When we talk about a photon, we express energy as hf and momentum as hf/c. The h is Planck’s constant of action, being 6.63 x 10-34 Joule-seconds. Action is energy multiplied by time, and also momentum multiplied by distance. The f is of course frequency per second, and the speed of light c is distance divided by time, which converts a measure of energy into a measure of momentum. What's important is that the photon isn't some "billiard-ball" particle. It isn't an object. It's an action. It's akin to a kick. OK now, try measuring a kick. You know it isn't an object, you don't expect it to have a shape or a surface. Because it's an action. And an action is only an action if there's some motion involved, so you can never pin down the location of a kick. You can only say where you detected it. Ouch! Another action is a shout. There's no specific place where it can be located at some point in time. It's a spherical compression wave in air expanding outwards, and whilst it has a centre, you can't go and stand next to my mouth and say "this is where the shout is". Instead, when you hear it, you say "the shout is here". And then somebody else hears it and says "the shout is here", and it's like it's in two places at once. That's what the quantum world is like. Once you understand that you aren't dealing with objects, it isn't mysterious at all. Edit: I should add that everything is like this. Not just the "objects", but the things you detect them with too. That's why things are uncertain.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now