Smell

Yeah we all know what is it, at times smells like shit, at times like a beautiful rose.
But what is smell? What is it made up of. Why or how do different things have different smells? If I smell a apple, then are apple particles going inside me or something?

yes.

So when I smell shit, shit is going inside me!?ewe
But what is smell?

Smell is one of our senses. It is a sensation we have in our noses when certain particles get sucked in there.

Trying to define it much further is like trying to define the colour blue.

we eat fecal matter when we brush our teeth, i dont think a few particles goin up your nose will cause to much damage

Uuuuh we do?

yep.
http://www.courierjournal.com/features/health/2004/02/hf-front-brush0212
-5683.html

I had read some time ago that smells are produced from oils in the air- there was a fantastic article in Nation Geographic many years back that talked all about smell it was very fascinating- it might still be kicking around here.....

some more fart facts a s well...
http://www.heptune.com/farts.html
answers many questions about farts not so many about the science of smell....