what did Mr. Heisenberg mean. think about it once?

Question

does the uncertainity principle mean that there will always be an uncertainity in 'the values measured of some physical quantities' or does it mean that there will be an uncertainity in 'the values existent of some physical quantities'? both the statements are different from each other. the first means that the values cannot be certainly measured and the second means that there is no certain value existent for them.

i personally think the second statement is more correct.

Answer 1

It is the second one... that there is an actual uncertainty in the velocity/position, not just the measurements. Look up the Einsten-Podolsky-Rosenberg paradox and Bell's Theorem for more information on this.

Edit: Apparently a lot of people aren't actually understanding the uncertainty principle. Yes, the original version says that both the position and momentum of a particle cannot be measured (or known). However, the principle has since been strengthened to say that a particle DOES NOT HAVE both a definite position and momentum.

This has nothing to do with observer effect, but is in fact (as far as we know) a basic fact about the universe. (Unless someone discovers a more basic fact that accounts for uncertainty.)

Answer 2

The Heissenberg uncertainty principle states that it is not possible to measure both the momentun of an electron and its position at the same time. Mathematically, it is quite complicated physics. However, the principle of uncertainty can be more broadly stated by saying that you cannot measure something, without altering the property you are measuring.

Take for example, measuring the temperature of a liquid. When you insert the thermometer into the liquid, the thermometer might be hotter or colder than the liquid, and would either warm it up, or cool it down, so the measured temperature will NOT be the temperature before you iserted the thermometer. In most cases, it wouldn't matter much, because the heat generated by the thermometer will not affect the temperature of the liquid much, because the thermometer is much smaller. Consider however, the case of a thermometer which is very large in respect to the volume of the liquid (say, both are the same volume). In this case, the effect that the thermometer has on the liquid may be very great, making the temperature measurement totally uncertain.

So it is at the scale of quantum mechanics: the electrons, or other sub-atomic particles, are so small that the uncertainty of measurement (or even of observation) is very great.

Answer 3

Two physical quantities of a system can only be measured accurately at the same time if their commutator is zero (paraphasing from W.Heisenberg, Z. Phys., 48, 172,1927)
So if you choose two parmeters (position and momentum are the standard ones) that are interdependent (commutate) then there will be some uncertainty in their magnitudes. Much more convicing is the fact that position is a particle property and momentum is wave-like so obviously something cannot be fully a particle and a wave at the same time.
The magnitude of the uncertainty is also uncertain some books say h/2*pi and some h/4*pi.

Answer 4

The First Statement holds true.
Both the position and the momentum cannot be measured above certain limit.
For a simple example:An electron is moving at a certain momentum and at a particular time is at a particular position. The position and the momentum is totally defined until and unless we start to measure either. When a photon(particle of light) strikes the moving electron, the momentum of that photon moves or pushes the electron so that it is not in its original position[i.e., before the photon hits the electron] In this way we are not able to pinpoint the position the electron.
The uncertainity caused by observation is called the 'Observer Effect'. Our act of observing the particle changes its position/momentum or other conjugate variables. You should understand that the things in the universe itself is not uncertain, it is only our observing that changes the originality.

Answer 5

He meant that there is a fundamental uncertainty in the measured values. You can know both the position and momentum of a particle at the same time, you just can't know them both to an arbitrary accuracy because of limits imposed by nature. However, this raises questions as to whether or not both properties are absolutely existant. If you can't know both the position and momentum values exactly, then does the object still have exact values for both of these properties? Does something you can never know anything about for certain still exist all the same?

Answer 6

Heisenberg gives the principle that "we do not measure the values of displacement and momentum at a time." This gives the uncertainity principle of Heisenberg. That is enough. Hence your 1st choice is correct.

Answer 7

It does"t mean that uncertainty in existence but uncertainty exists in measuring the quantities according to Heisenberg's UN-certainty principle we can't measure two physical quantities simultaneously there is all ways an uncertainty in measurement only.

Answer 8

well, perhaps you can decide your own answer from this.

if im not wrong, the uncertainty principle states that its never possible to know BOTH the position and velocity of a particle e.g. electron at the same time. We can take a 'snapshot' of an electron and see its position or use other methods to determine the velocity or spin of the electron, of which eludes me, but we can never determine both at the same time. Since the most basic considerations we have are that of displacement, velocity and acceleration when we consider the motion of a particle, the motion of a particle is never certain.

hope this helps=)

Answer 9

acc. to the Principle both position and momentum cannot be calculated exactly.
there is uncertainity in any one of them.If one is more uncertain then the other is more certain and vice-versa

Answer 10

i too think the second statement holds better than first statement