Playing outside in the fresh air is so healthy and good for a kid, right? Well, Tasha Sturm decided to see just how much bacteria was on her son's hand after he had been playing outside. Sturm, a lab technician at Cabrillo College, California, had her son press his hand into tryptic soy agar jelly, incubated it, and after a few days the bacteria below showed up! Don't worry though, it's perfectly normal to have some bacteria on your hands. In fact, being exposed to a safe amount of safe bacteria is necessary for a healthy immune system.