Source: http://en.wikipedia.org/wiki/Synthetic_oil

For detail, refer to the website.

Synthetic oil is oil consisting of chemical compounds which were not originally present in crude oil (petroleum) but were artificially made (synthesized) from other compounds. Synthetic oil could be made to be a substitute for petroleum or specially made to be a substitute for a lubricant oil such as conventional (or mineral) motor oil refined from petroleum. When a synthetic oil or synthetic fuel
is made as a substitute for petroleum, it is generally produced because
of a shortage of petroleum or because petroleum is too expensive. When
synthetic oil is made as a substitute for lubricant refined from
petroleum, it is generally to provide superior mechanical and chemical
properties than those found in traditional mineral oils.

Read this

http://en.wikipedia.org/wiki/Motor_oil

http://www.carbibles.com/engineoil_bible.html


Actually no need to read, one change car in less than 10 years, no need to bother too much .... your engine won't fail you so easily unless you're extreme ....

http://www.bobistheoilguy.com/whatisoilanalysis.htm

Read for the sake of reading?

I think for fun, i'll do a UOA on my motul 300v 5w30 on an 100k engine. Let's see what is the figure and what story it is going to tell