Bacteria:

Use petri dishes and agar to grow bacteria.

• What effect do household cleaners have on a bacteria culture? What about temperature? What is the best or worst environment in your house for bacteria growth?
• Are there substances in your kitchen (garlic, red pepper, curry, tea tree oil, etc.) that have natural antibacterial properties?
• Use the Gram stain method for testing whether Gram-positive or Gram-negative bacteria is more common in your house. Do common antibiotics interact differently with Gram-positive and Gram-negative bacteria?
• Studying mold growth conditions also makes an interesting experiment. What types of food mold the quickest? How does temperature affect mold growth? Are there some practical ways to slow down the growth of mold? Experiment with different types of preservatives to see how they prevent mold growth.
• Does bacteria grow in a predictable pattern? Try an experiment by making thumbprint, fingerprint, or handprint bacteria cultures using agar and petri dishes.
• How much bacteria grows in the mouth and what effects do common cleaning techniques have on bacteria growth? Consider brushing with a dry toothbrush, comparing different toothpastes, mouthwashes, and flossing as well as time spent cleaning teeth to find which methods work best to keep the mouth clean.
• Is a dog's mouth really cleaner than a human's?
• Use GloGerms to simulate the behavior of germs. Experiment to find the best ways to eliminate germs from hands and surfaces. (Test water temperature, soaps, length of time spent washing, etc.)