A stubborn belief says microwave ovens heat food from the inside. In fact, the waves only penetrate one to a few centimetres. There they jostle water molecules, and the heat then reaches the centre by conduction, just as in a regular oven. That is why a large dish stays cold in the middle unless you stir it.
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.