A dipole moment is a measure of the separation of positive and negative electrical charges within a molecule. It indicates the polarity of a molecule, which affects how it interacts with other molecules and external electric fields. The dipole moment is represented as a vector, pointing from the negative charge to the positive charge, and is quantified in units called Debye (D). In simple terms, molecules with a significant dipole moment, like water (H2O), have a positive end and a negative end, making them polar. This polarity influences properties such as solubility and boiling points, as polar molecules tend to interact more strongly with other polar substances.