A corn kernel holds a little water sealed inside a tough hull. As it heats, the water turns to steam and the pressure climbs to around ten times atmospheric pressure. At about 180 °C the hull suddenly gives way: the softened starch puffs into foam and sets instantly. The pop comes from the escaping steam.
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.