Lord Rayleigh noticed that nitrogen taken from air was about 0.5% heavier than nitrogen made chemically. Refusing to dismiss the gap, he investigated with William Ramsay and in 1894 isolated an unknown gas that makes up almost 1% of the air you breathe. Since it barely reacts with anything, they named it argon, Greek for "lazy."
Cooled below −183 °C, oxygen turns into a pale blue liquid. Pour it between the poles of a strong magnet and, instead of flowing away, it hangs suspended between them. The reason lies in its unpaired electrons, which respond to the magnetic field. Liquid nitrogen, by contrast, is colourless and pours straight through.
In 2012, Felix Baumgartner jumped from a capsule hanging beneath a balloon, about 39 kilometres up. In that extremely thin air almost nothing slowed him down, and he reached around 1,358 km/h in free fall, or Mach 1.25. He became the first person to exceed the speed of sound with nothing but his own body.