Question

what are cohesion and adhesion?

Answer 1

Cohesion allows similar molecules to stick together. For instance, water molecules are generally in a beaded form when it's on a car after it rains. Whereas, adhesion occurs when a molecule can stick to a substance. Such that: an adhesion performs like glue to another object. We could say, if a piece of paper gets wet the water basically sticks to that.

Answer 2

Cohesion is the property of a substance by which its molecules are attracted to each other.
eg: mercury
Adhesion is the property of a substance by which it is attracted to molecules of another substance.
eg: Water