That's what a lot of people were asking at the 2009 Intel International Science and Engineering Fair in Reno a few months ago. Two 16 year olds in San Antonio, Texas, worked together to try and find out. Keystone High's Sehar Anjum Salman and Jada Nicole Dalley showed that third hand smoke—all the toxic chemicals left behind on furniture, car upholstery or clothing after the cigarette smoke floats away—produces as many mutations in newborn fruit flies as second hand smoke—when someone blows their cigarette smoke near you and you breathe it in.
These photos taken by Jada and Sehar show some of the fruit flies they used for their study. Different genetic mutations can affect the color and shape of the flies' eyes, the color of their bodies, the shape of their wings, the number of bristles they have, and many other features. Compare the normal fruit fly (left) with the mutant fruit fly (right) - do you see a difference? (Hint: the mutant fruit fly is probably going to have some trouble flying).
Sehar and Jada won a First Place NIDA Addiction Science Award at the Super Bowl of science fairs for cleverly showing the dangers of third hand smoke—something scientists don't know a lot about. It makes you think twice about hanging out with smokers, even if they're not lighting up! For more information on Sehar and Jada's project, see NIDA's Web site.