The chemist who changed the planet’s atmosphere more than any other living thing in history; the physics of falling bullets; why two events can be both simultaneous and not simultaneous at the same time; and old people smell.
Thomas Midgley Jr. invented leaded fuel and CFCs; he may have done more damage to our atmosphere than any other single living creature in history.
If you fire a gun straight up into the air, what happens when the bullets fall down again?
Einstein was the first to discover that two events can be both simultaneous and not simultaneous, depending on your frame of reference.

Is there a chemical basis for the distinctive smell of old people?
For more about the highs and lows of alchemy and chemistry, and the surprising and counterintuitive corners of physics, begin here: