Can someone explain quantum physics?

[TeaFan]

It can be pinned down, but then you cant know how fast it is moving. This is the famous Heisenberg uncertainty principle:

 

The more precisely you measure the location of a proton (in this case) the less precisely you (or the larger the uncertainty) measure of the momentum of the proton. So basically you can know exactly where it is or what its momentum (this is the mass of the proton multiplied by the velocity, so you could think of it giving you information on the velocity) is but you *cannot* know both quantities simultaneously.

 

 

I think I will get the book that ladyacademic recommended. I'm probably below the level of a gifted kid, but it never hurts to try and make your brain work every now and again (mind you, I tried that recently with Neitzsche - brainhurt! brainhurt!).

 

Anyway - I am now thankfully clear on the proton issue thanks to nightrider. Is it too cheeky/lazy of me to now ask "why is this significant?".

[blackspot]

In plain English. I don't have a scientific brain - is there anyone who can explain the basics of quantum physics for me? (I have done some philosophy, and I understand that quantum physics sort of comes under that heading, but I don't understand what it is).

 

go and buy thr dvd called--------- what the bleep do we know it explains it all very good dvd:thumbsup:

[TeaFan]

I think I will get the book that ladyacademic recommended. I'm probably below the level of a gifted kid, but it never hurts to try and make your brain work every now and again (mind you, I tried that recently with Neitzsche - brainhurt! brainhurt!).

 

Anyway - I am now thankfully clear on the proton issue thanks to nightrider. Is it too cheeky/lazy of me to now ask "why is this significant?".

 

Actually, I think I might have worked it out. Is it that in order for something to be said to exist (in the sense that we generally understand the concept), something has to exist in both time and space. But if we can only locate sub-atomic particles in either time or space, we cannot be certain that things made up of atomic and sub-atomic particles actually do exist? Or did I get that quite wrong?

[nightrider]

I think I will get the book that ladyacademic recommended. I'm probably below the level of a gifted kid, but it never hurts to try and make your brain work every now and again (mind you, I tried that recently with Neitzsche - brainhurt! brainhurt!).

 

Anyway - I am now thankfully clear on the proton issue thanks to nightrider. Is it too cheeky/lazy of me to now ask "why is this significant?".

 

Well most/many/all people would assume if you had a measuring device that measured position to an infinite precision (so that you were completely certain where the proton) and another measuring device that measured the momentum to infinite precision you could indeed know both the exact position and exact momentum.

 

What the uncertainty principle does is tell us this seemingly obvious statement above is simply wrong which goes against what we might think on the surface (after all we are all used to seeing where a car is located and measuring its speed).

 

If we call the two uncertainties A and B then what the principle states mathematically is A times B is always larger than a number h (which is very small). So there is a limit on how small you can make the product of A and B and hence A and B cannot both be infinitely small.

[defstef]

go and buy thr dvd called--------- what the bleep do we know it explains it all very good dvd:thumbsup:

Unfortunately, the whole film is nothing more than pseudoscientific bunkum which uses wooly half-truths to lend credence to preposterous mystical ideas. I'd suggest people watch it for a laugh, although it is actually (quite worryingly) the front for a cult, while simultaneously being one of the highest grossing documentaries in US cinemas (perhaps not surprisingly - they should have got Morgan Freeman to narrate it, though - that would've nudged it into top place).

This Columbia University maths department blog: Not Even Wrong (the title a tribute to the late, great Wolfgang Pauli) and this brilliant, short review in NewScientist should hopefully convince you of how ridiculous it is, but if you need convincing, type: |"what the bleep do we know?" "scientific accuracy"| into Google...

 

I'd still recommend "In Search of Schrödinger's Cat" and "Schrödinger's Kittens" by John Gribbin or "The Fabric of Reality" by David Deutsch to anyone wanting to find out more (and avoid wacky American cults).