A candle does not burn solid wax: heat melts it, the wick draws it up, and it then vaporises. In the flame, some of that carbon forms tiny grains of soot heated beyond 1,000 °C. These are what glow yellow. Near the base, where oxygen is plentiful, combustion is complete and the flame stays blue.
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.