Van der Waals forces are weak attractions that occur between molecules or parts of molecules. These forces arise from temporary shifts in electron density, leading to slight positive and negative charges. They play a crucial role in various physical properties, such as boiling and melting points. There are three main types of Van der Waals forces: dipole-dipole interactions, induced dipole interactions, and London dispersion forces. Although individually weak, these forces can collectively have a significant impact on the behavior of substances, influencing how they interact, bond, and form structures in both gases and liquids.