Microbiologist  Tasha Sturm, takes handprint of her son after playing outside and incubates the results.

[youtube https://www.youtube.com/watch?v=wWMOly7mA5c?feature=oembed&w=540&h=304]

On the one hand we know that bacteria can be really harmful, on the other hand it seems that if we learn more about them, they can be helful and useful to us.