How do I Grow Bacteria in Test Tubes?
Bacteria are microscopic organisms that grow and live everywhere, from the human mouth to the surfaces we touch. Humans carry bacteria, some of which are harmless and some that can cause serious illnesses. To study bacteria and learn their effects, students grow them in designated Petri dishes or test tubes. Students looking for an educational science fair project or experiment for science class can grow their own bacteria.
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Things You'll Need
- Fat free chicken or beef broth
- Stove
- Pot
- Coffee filter
- Pipettes
- Infected liquid
- Incubator
Instructions
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Boil fat-free chicken or beef broth in a stove-safe pot. Boil for one to two minutes and then remove the mixture from heat. This will prepare a sterile environment to grow your bacteria.
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Allow the broth to cool to room temperature. Filter the broth through a coffee filter or another clean cotton cloth until it runs clear.
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3
Transfer 10 mL of broth solution to a test tube. Add two mL of saliva, tap water or another liquid that contains bacteria. Cap the test tube. Use multiple test tubes if you want to test different locations for bacteria.
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4
Place the test tube in an incubator, which is any place where the temperature is near 90 degrees Fahrenheit (35 degrees Celsius). The bacteria should grow within three days. You will know they are growing because the liquid will become cloudy or develop a foul smell.
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Tips & Warnings
If you want to use your saliva to grow bacteria, take a sample in the morning before you brush your teeth or rinse your mouth. Cleaning your mouth eliminates the bacteria.
Purchase equipment for this experiment at science supply stores, hobby stores or Internet retailers.
Use a greenhouse or warm cabinet for an incubator, or purchase a professional incubator.
Do not come in direct contact with the bacteria once they start to grow, as some bacteria can cause serious illness.
References
- Photo Credit Bacteria Colonies image by ggw from Fotolia.com
