## Conceptual question

$\Delta p \Delta x\geq \frac{h}{4\pi }$

Dakota_Campbell_1C
Posts: 51
Joined: Fri Sep 28, 2018 12:15 am

### Conceptual question

Why is it that we can only know the measurement of either the position or momentum at a given time? I don't understand the idea behind this equation.

Brian Chhoy 4I
Posts: 66
Joined: Fri Sep 28, 2018 12:16 am

### Re: Conceptual question

It plays into the fact that we are only talking about a particle with very little mass, such as that of an electron. When trying to measure the speed of a particle passing by we would count how long it takes to move from one position to another. However, when you do so you are messing up the original path that the particle was going to take and thus have more uncertainty in its position when trying to be more certain about its momentum. The process of measuring its speed would usually involve using a light beam to measure when it passes the two positions. However, since the mass of the electron is so small, the photon hitting the electron can actually cause it to move away form its original path and thus altering our certainty in its position.

Nicholas Kull_3L
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am

### Re: Conceptual question

Heisenberg's Uncertainty Principle states that complementarity (the impossibility of knowing both the precise values of either momentum or position simultaneously), is the reason why, and that position and momentum are inversely related. Once a value of either is known we have to use the uncertainty symbol delta to describe the momentum or position.