what is the difference between adhesion and cohesion?

The difference between adhesion and cohesion lies in the type of molecules involved in their attractive forces. Adhesion is the force of attraction between molecules of different substances, such as water molecules sticking to glass. Cohesion, on the other hand, is the force of attraction between molecules of the same substance, such as water molecules sticking to each other to form droplets. Adhesion causes liquids to spread across surfaces, while cohesion causes liquids to form droplets. Both forces are crucial in phenomena like surface tension and capillary action, and they result from different molecular interactions—adhesion involves interactions between dissimilar molecules, often including hydrogen bonds and van der Waals forces, while cohesion is mainly due to intermolecular forces within the same substance.