As a SIIT college student, based on what Mrs. Forcadilla taught us,

the Two kinds of Weathering are

Mechanical- physical forces that broken down rocks into smaller pieces.

and

Chemical- informed transformation of rock into non-chemical composition.

Well, there are a few answers to that:

1. Maybe he just wants to siit next to you like a friend

2. This is the most likely one, he probably has feelings for you, behond friendship and wants you to know.

3. There could be a chance his friends simply dared him to do this but I doubt it.

Ask him if he likes you, he'll probably say yes!!!!