If an atom's nucleus were the size of a marble, its electrons would roam hundreds of meters away, making the atom as big as a stadium. Nearly all of its mass sits in that tiny core; the rest is essentially empty space. What feels “solid” when you touch a table is mostly electric forces pushing electrons apart.
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.