What does adhesion refer to in terms of water molecules?

Adhesion in the context of water molecules describes their tendency to cling to other polar surfaces. This phenomenon occurs because water is a polar molecule, meaning it has a partial positive charge on one side (the hydrogen atoms) and a partial negative charge on the other side (the oxygen atom). When water comes into contact with other polar substances, such as glass or plant tissues, the attractive forces between the water molecules and the molecules of the other surface facilitate this clinging.

This property of water is significant in various biological processes. For instance, it plays a crucial role in the movement of water in plants through capillary action, where water travels up through narrow tubes against the force of gravity. This ability of water to adhere to other polar surfaces demonstrates the importance of polarity in affecting interactions among molecules in biological systems.