Question

Problem 9

: You are sitting in a coffee shop again, and overhear the following:

“I still don’t understand the Heisenberg uncertainty principle. It says that we can never know an

object’s exact momentum and an object’s exact position. But look at this coffee mug. I know

exactly where it is – it’s right there. And I know its momentum exactly – its momentum is exactly

zero because it isn’t moving. Doesn’t this disprove the uncertainty principle?”

How could you respond to this?

Answer 1

Ans.

The Heisenberg princple works in the realm of atmoic particles (microscopic particles). If we measure the uncertainty of product of position and momentum of the mug (how are we sure that speed is exact zero we need to measure it and there arises uncertainty. Similarly we have uncertainty in the position of the mug) , the uncertainty would be very very small of order 10^-30 which is very hard to detect.

So, this doesnt disporve the uncertainty principle as the coffee mug is not microscopic particle.