can somebody xplain the heisenburg's uncertainity principle?

Question

i dont understand y is it impossible to locate the position and
velocity of an electron simutaneously....... it seems... well......
i dont know......
i wonder what is this- '' probability''

Answer 1

I'll try to explain it through a real world analogy; first in QM it is necessary to note that Heisenberg said position and momentum, rather than velocity.

Picture a person running, this person is going to represent the electron... If you freeze that person in time, say on a piece of film you can get a fairly accurate position for them. However from that snapshot you can not see how fast they are moving nor how much mass they have (these two things are their momentum). Now say you video tape or otherwise tag this person to calculate their velocity, you have a change in position over a change in time which means this can not be done at a single instance, but electrons like people do not have to move in a single path there is however a probability of which path it is likely to take and therefore its next likely position. Now to get the mass think of it this way, like people two electrons do not have to have the same mass so the assumption that one electron=another will not work, not to mention that at extremely high velocities mass can change into energy. Now there is a way to measure the momentum directly and and that is to measure the force that is exerted by the object during a certain time interval, this still requires a change in time.

It essentially boils down to the fact that this principle deals in two different frames that coexist, position is done in any individual frame and can only be known at that one instance, while momentum is done over a range of times.

Answer 2

I struggled searching the web for a simple explanation which we all can comprehend. It is possible to reproduce the mathematical language and complicated terms. That would not make sense for us. Suffice to say that even with the infinitely precise instrumentation it is impossible to determine, at the same time, the POSITION and MOMENTUM of an electron. In other words it is impossible to say where an electron is and where it is going at the same time. This matter pertains to Quantum Mechanics which deals with energy of sub-atomic particles.

Answer 3

In the world of quantum mechanics the idea that you can locate both the position and momentum of a particle is uncertain, and probability is the likelihood the answer is correct. Try this and see if it helps you, it's a fairly concise explanation.

http://zebu.uoregon.edu/~imamura/208/jan27/hup.html

Answer 4

It means that the postion and momentum cannot be determined to 100% accuracy. i.e. if we are using an electron microscope to locate an electron, the photons from the microscope that hit the electrons displace it, changing its position and momentum. If we reduce the resolution(i.e. no. of photons emitted by the microscope), the image on the screen of the microscope appears blurred, again making it difficult to determine the position and momentum of the electron.

calculations showed that

if uncertainty in position - x
and uncertainty in momentum - p

then x * p >= h/4(pi)
where h - plancks constant

p=m*v
where v - uncertainty in velocity
therefore x*m*v >= h/4(pi)

or x*v >= h/4(pi)(m)
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HAPPY NEW YEAR

Answer 5

The principle is related with operators concerns position(p) and momentum(x) of a quantum mechanical particle that arises from the fact that [ x , p ] is not equal to zero.

dP dX > h/2

Answer 6

Basic to the principal is the concept of zero time.
Any entity in the universe is isolated in time. Any direction they look,they are looking into the past.
It may be a millionth of a second but until the information reaches you its existence is uncertain!

Answer 7

Very, very crudely, you can know everything about the position of a particle and nothing about it's speed.

Or you can know exactly how fast it is moving and nothing about it's position.

Or you can know a bit about each quantity. The more you know about position, the less you know about velocity and vice versa.

Answer 8

See http://en.wikipedia.org/wiki/Uncertainty_principle