Q:

What causes anything to smell?

We all know that we can see anything because of Light Absorption and all. We can hear things because of caused vibrations. But what makes an object smell? I read somewhere about the presence of odorous chemical compounds in the objects which makes them smell. Then, What gives smell to those odorous chemical compounds?

A:

What gives smell to those odorous chemical compounds

Your nose and your brain. First of all, there are just some molecules flowing through your nose. There are many receptor neurons that react to those molecules and send "signals" to your brain. In the end, you smell something.
It's the same with light: light really is just an electromagnetic wave of certain wavelength and humans happen to have cells that react to such waves.

