Lets Experiment!

Have you ever walked down the street and had a random stranger smile at you? Did it make you happy? Did you smile back? Let's investigate whether smiling is contagious. You'll need to think of a way to design your experiment. One option would be to take a walk around a park and keep track of how many people smile at you, and whether those numbers change based on whether you smile at them or not. Or maybe you want to see if smiling has a chain reaction by having a friend walk a little ways behind you and see if the number of smiles he or she receives changes depending on whether you smile at the passersby first. However you design your experiment, make sure you're observing many people so that you can draw accurate conclusions!

Inspired from: http://www.sciencebuddies.org/science-fair-projects/project_ideas/HumBeh_p042.shtml