What Is Quantum Mechanics Good for?

It is “good for”: Explaining the bizarre manner in which certain elementary sub-atomic particles behave.

If you roll a marble, you can be pretty certain where it will move to using “Newtonian Mechanics”. This is not true when a very small sub-atomic particle like an electron or photon moves.

The best one can do is to calculate a “probability “ value for the eventual destination of the particle.

It is a bit like predicting what the result will be if I roll a pair of dice.

the probability that the sum of the top two faces is “two” (from 2 “ones”) is 1/36, but the probability of getting a sum of “four” is three times higher at 3/36 - since {1,3} {2,2} or {3,1} are all just as likely as the single {1,1} combination that gives a “two”.

Quantum Mechanics is also essential in attempting to come up with a “Grand Unified Theory” of matter. Such a theory would go a long way towards explaining how and why the universe exists, and how we may gain best advantage from the natural Physics of the universe, e.g. finding new ways of extracting mater from any source of matter, (or even perhaps from empty space).

– Best wishes - Majikthise.