Under normal conditions on earth, the separation between liquids and gases is usually a bit mundane: the level of water in a drinking glass simply falls as the liquid evaporates into a gas, since the liquid is denser. Two liquids of different densities, such as the oil and vinegar of salad dressing, are similarly unexciting; the oil just floats to the top after a period of time. However, when the effects of gravity are taken away, such as in the environment of the International Space Station (ISS), this separation creates far more interesting and complex patterns.
