Click for more "Microbes After Hours" videos Most of the
microbes on our bodies and other surfaces are harmless, but some
are pathogenic or disease-causing. For this reason, we want to
control the number of microbes around us. The odds of becoming
infected increase with the number of microbes on surrounding
objects. But what can we do to affect the number of microbes on
surfaces around us? In this activity, you will test a chosen
fomite for the presence of microbes and the effects of a
disinfectant by growing colonies of bacteria in a medium on
petri plates. A medium has food, vitamins and salts that help
microbes grow. You usually don’t see bacterial colonies like
those that form on petri plates on everyday surfaces. That’s
because there is rarely such a perfect concentration of
nutrients on fomites in nature. Note: This is an activity that
you will start on one day and finish on a different day. What To
Do: 1. If you have long hair, tie it back to keep it from
dangling into the petri plates as you’re workin