Which liquid gets solid when heated?

Why does everything change from a solid to liquid as it is heated but when you boil an egg and it gets hotter it changes from a liquid to a solid?

• Answer:

  When You heat things, you add energy to them. When this energy is sufficiently high, bonds between molecules start to break, and that's how you get melting of solids, or boiling of liquids. In eggs, the bonds that break are intramolecular bonds that keep the molecules in the eggs (the proteins) in a certain structure (like a helix, or a sheet for instance) - i.e. bonds between one part of the molecule to a different part of it. When those bonds break, the proteins are more prone to form other bonds, this time intermolecular ones, and when you get enough of those, you get a solid.