...my friend and I did an experiment to see the effects of UVC on bacteria without the need for a microscope. I've done this loads of times by the way (for schoolwork). You can see the steps here (in case you want to try it yourself or if your child wants to grow bacteria or fungi for a school project). By the way, instead of Beef stock powder, you can use Knorr Beef Broth Cubes. And, if you're scared to do a swab from the stuff in your house (or from the inside cheeks of your mouth or under your finger nails), you can use yogurt (remember, it has live, good bacteria).