A diamond is just carbon, like coal, with its atoms arranged differently. Heated to several hundred degrees in oxygen, it burns and turns into carbon dioxide, leaving no ash at all. In the 18th century, Lavoisier and then the English chemist Smithson Tennant burned diamonds, proving they were made of carbon.
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.