Question

How did Heisenberg discover the uncertainty principle?

Answer 1

I'm not sure???? Sorry, couldn't resist!

Working on the new quantum theory, Heisenberg discovered a problem in the way that the basic physical properties of a particle in a quantum system could be measured.

Explanation:

OK... rest of the real history is here:
https://www.theguardian.com/science/2013/nov/10/what-is-heisenbergs-uncertainty-principle