- What is Mechanics? A part of the car which always breaks down?
  And Thermodynamics? A kind of aerobic, but in hot springs?
These are branches of Physics. Mechanics is a Science on motion, thermodynamics - science on heat.
- And what is Physics?
- Physics, by an ancient thinker, Aristoteles, is the knowledge of Nature,
  i.e. on everything that you can touch.
- So I can touch Physics?
- Sure! And everything what you can NOT touch was, by Aristoteles,
  called extra-nature or metaphysics.
- So may I play with it
- Sure! And you will certainly discover something.

Welcome in playing-with-everything-that-you-can-touch. At least virtually, i.e. on the computer screen.

(And what we can not touch, let's leave it to meta-physicist.)