Question

can anybody explain the uncertainty principle to me?

Answer 1

By observing a phenomena you change it. Thus any measurement you try to take there will always be a certain amount of 'uncertainty' or innacuracy related to it. For example measuring the current flowing through a circuit you must place an ammeter in that circuit, which itself has a resistance and changes the flow of current.

Answer 2

If you're referring to Heisenberg's Uncertainty principle, it follows as a result of quantum mechanical laws. Instead of being assigned specific values, systems are described by their so-called "wave function." This wave function contains all possible states that a system can be in as well as the probabilities of being in that state. When a system is then observed, that wave function "collapses" in that only one state remains and it's assigned a probability of 100% (since you just observed it in that state).

The problem is that some properties cannot be measured simultaneously. In Quantum Mechanics lingo, this is referred to as the properties not "commuting". What this means is that the information that one property "extracts" from the wave function is lost if another property is observed beforehand. Specifically, observing where an electron is causes its wave function to collapse. This, however, means that some information is lost; information that would have been necessary to accurately measure the momentum/velocity of said electron. In fact, if we were to measure the position of an electron without error, it would be absolutely impossible to measure its velocity as that information was lost when its position was observed.

When something is measured with an uncertainty, remnants of information are left over that allow a similar measurement (with uncertainty) of a noncommuting property. For this reason, the product of such two uncertainties must be greater than a certain constant.

For the record: what SeanEEE described isn't actually an uncertainty principle, as the uncertainty principles doesn't imply that exact measurements are impossible, just exact measurements of two noncommuting properties.

Answer 3

its simple..u cant calculate actual speed and location of particle at same time..

Answer 4

Thank you. I realize I'm cramping your style by asking stupid questions, but honestly I didn't know who else to ask. My professor isn't very good at dumbing it down for us non-physics majors.

Answer 5

Of course these are all correct, later Einstein along with 2 other famous physicists would cleverly create the theory that you could get past such a dilemma by measuring a seperate piece. For example if you had a collision and 2 electrons flew in opposite directions at the same speed, measuring one would indirectly give you the same information for the electron you did not measure, without "contamination" of the electron you are indirectly measuring.