I'm just currently reading my science book and I just thought of a few questions.. Why are water molecules have a high attraction of glass? And why are their adhesion higher than their cohesion?
The high attraction between water molecules and glass is due to a phenomenon called "polarity." Water molecules are polar, meaning they have a partial positive charge on one side (hydrogen atoms) and a partial negative charge on the other side (oxygen atom). Glass is also polar, with some of its atoms having a partial positive charge and others having a partial negative charge.
To explain why water molecules have a higher adhesion to glass than cohesion between one another, we need to understand cohesion and adhesion. Cohesion refers to the attraction between molecules of the same substance, while adhesion refers to the attraction between molecules of different substances.
In the case of water, the strong hydrogen bonding between water molecules creates a cohesive force that holds them together, giving water its high surface tension. However, when water comes into contact with glass, the polar water molecules are attracted to the polar glass molecules, resulting in adhesion.
Adhesion is higher than cohesion for water because the attractive forces between water and glass are stronger than the cohesive forces between water molecules. The polar nature of water and glass allows them to form hydrogen bonds, which are a particularly strong type of intermolecular force. These hydrogen bonds between water and glass overcome the weaker forces of cohesion within the water, causing water to spread out on a glass surface instead of forming droplets.
To summarize, the high attraction of water molecules to glass is due to the polarity of both substances. The adhesion of water to glass is higher than its cohesion because the attractive forces between water and glass are stronger than the cohesive forces between water molecules.