Freefalling on a NASA astronaut trainer plane. ZeroG is a physics lesson about the difference between weight, mass, and momentum. Zero weight, but it still hurts when bumping around. Not to much though. Point being that a 170 pound person may weigh zero pounds in zero gravity, but they still hit...

Quantum Physics amazing Double Slit Experiment.

Galileo Galilei (15 February 1564 -- 8 January 1642) was an Italian physicist, mathematician, astronomer, and philosopher who is closely associated with the scientific revolution.