Bacterial Petri Dish Culture Garden

Project Overview: Real biotechnology labs use Petri dishes filled with agar to grow and study bacteria, but you don't need anything fancy to build your own version at home. In this project, you'll make a homemade "agar" out of gelatin and broth, then swab different surfaces around your house to see just how much invisible life is living all around you.

Materials Required:

1. 2 cups water

2. 2 beef or chicken bouillon cubes

3. 2 tablespoons unflavored gelatin

4. A small pot 

5. 3 to 4 small clear plastic containers with lids 

6. Cotton swabs

7. Tape and a marker (for labeling)

Instructions:

1. Heat the water with the bouillon cubes until fully dissolved, then stir in the gelatin until it dissolves completely.

2. Carefully pour a thin layer of the warm mixture into each plastic container, let it cool and firm up in the fridge for about an hour, with the lids left off until set.

3. Once firm, label each container with what you're about to test (for example: "doorknob," "phone screen," "hands before washing," "hands after washing").

4. Rub a cotton swab firmly across each surface, then gently sweep it in a zigzag pattern across the surface of your gelatin.

5. Put the lids on, tape them shut, and store the containers in a warm, undisturbed place for 3 to 5 days.

6. Check daily without opening the lids, and observe any colonies of mold or bacteria that begin to grow.

Congratulations, you just cultured your own microbiology samples at home.

Fun Fact: Scientists estimate there are more bacterial cells living on and inside your body than there are human cells, most of them completely harmless, and many of them actually helping you stay healthy.