Quoting Eilennaei (Reply 19):
*On the other hand, we know that even with a single atom a full description will be impossible because an act of measuring will destroy the very information needed. This is one quantum effect* |

yes that is "collapsing the wave function", that is one of the basic principles of quantum mechanics, as well as the uncertainty principle, if you measure position very every very accurately (with minimal error)you compromise your momentum measurement and vice versa.

Quoting Pope (Reply 17):
*Can someone explain this in simple terms?* |

another way to look at the entanglement Eilennaei mentions, is as follows..(I will try my best):

imagine flipping a coin, before you disclose the outcome on your hand, we all know there is a 50 - 50 chance to get heads or tails. this is because we assume the coin is "COMPLETELY RANDOM".

However what If I tell you that before you lift your hand, the coin is actually in a superposition of heads and tails??? that sounds weird...i mean how can it be heads or tails at the same time....

but it turns out that at the atomic level this actually happens....you get these "weird states" where physical properties

CAN be in a SUPERPOSITION i.e both at the same time...or even weirder...things can be in many places at the same time...

so it turns out that you can manipulate these superpositions, and take advantage of the fact that things are delocalized and (in our example delocalized is the coin being head and tails at the same time) to get usefull outcomes.

In communication, you can think of having two coins....you flip them and before you disclose the answer...you could say they are in a weird superposition...they are "entangled"

So metaphorically, what scientist are doing is, manipulating these superposition of two coins and get them both to ALWAYS land heads or ALWAYS land tails....not random any more!!

so you ask how do you do that....thats because the two coins were not REALLY random, they were in a superposition that we understand and can manipulate.

Now if the two coins were miles apart but "entangled", then to continue our analogy, if one can affect the outcome of the other and do so in a predictable way then one can convey information from one point to another miles away!

I don't claim to have the best explanation, but I gave it a shot...

particles and waves are the same thing, but who knows what that thing is...