Bacteria in a petri dish

Students grow bacteria from unwashed and washed hands on petri dishes.

Steps

1. Prepare petri dishes with agar.
2. Students touch the agar with unwashed and washed fingers.
3. Close the dishes and observe for a few days.
4. Compare the colonies.

Tip: Do not open the dishes after cultivation; throw them away closed.

Materials needed

• Petri dishes with agar (1 set)