Van der Waals forces are weak attractions that occur between molecules or parts of molecules. They arise from temporary shifts in electron density, which create small, fluctuating dipoles. These forces play a crucial role in various physical properties, such as boiling and melting points, and are significant in the behavior of gases and liquids. There are three main types of van der Waals forces: London dispersion forces, dipole-dipole interactions, and dipole-induced dipole interactions. Although individually weak, these forces can collectively have a substantial impact on the structure and stability of larger molecules, including biomolecules like proteins and nucleic acids.