I have been thing about this, seems logical in a way, most reactions increase with concentration surface area, temperature and catalysts. Some of the factors are listed here:- http://library.thinkquest.org/12497/factors.htm They seem pretty similar to the one I put in the answers to my Chemistry A level (a level below degree level, but I went on to do electronics instead). You see some people say talking to plants improves them and I was wondering if this could be due to them breathing out more concentrated CO2, or maybe it is a load of rubbish, I don't know. I am growing some plants so I might start talking to some of them as an experiment!! Makes a change from talking on here lol Anyway this link says so:- http://www.timesonline.co.uk/tol/news/science/article6539405.ece I am not sure if that is peer reviewed, but anyway they were played music so I guess that's not the same.