In 1989, a Hitachi team fired electrons one by one through the equivalent of a double slit. Each electron leaves a single dot on the screen. Yet as thousands of hits pile up, interference stripes emerge, exactly like a wave would make. Each electron behaves as if it took both paths at once, something classical physics simply cannot explain.
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.