Earlier this school year, the kids both did Petri Dish labs.
Jay tested if toothpaste killed germs, if soap killed germs, & if antibiotic ointment killed germs. He also grew cultures from his & Dea's toes and yogurt.
Dea tested 4 different antibiotics. We got antibiotic discs to use for the lab. She collected samples from the most disgusting place in the house (the toilet) and tested the different antibiotics to see what effect they had.
For extra fun, we tested the antibiotics on water from the local river. Each dish has 2 antibiotics - one on each side & river water on both sides.
The results were somewhat disturbing. The river water ate through the gel, and the antibiotics had no effect at all.