write a paper on alcohol. Why we can't drink 200 proof alcohol (pure alochol has benzene in it, it will kill you) how the different concentrations affect the body and how ethanol is used as a common solvent in the lab and what its good for. That kinda touchs your topic I guess.
The acid rain one isn't bad, You could do the Haber process, which deals with concentrations of production of ammonia from nitrogen in the air, its really famous.
You're not drunk if you can lie on the floor without holding on
(n.): Something that can be looked down on and approved of at the same time.