"In a sense, a liquid is like a very fine powder made of particles with on the order of 10-20 molecules each. However, unlike a fine powder, the particles are constantly trading molecules as bonds break and reform throughout the liquid.

Another analogy is that a liquid is a gas whose molecules are held in close proximity by the external pressure - the pressure of the air. And in fact, the boiling point of a liquid and the melting point of a solid both depend on the external pressure. There are no liquids in a vacuum."