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Easy Kids Science Fair Experiments About Germs

by Darlene Peer, studioD

Science projects about germs can show kids how germs are transferred to our hands and bodies when we touch surfaces. It's a chance to think about how many people touch different surfaces and how often those surfaces are washed. It's also an effective way to remind everyone to wash their hands on a regular basis.

Bacteria Grows Quicker in Damp Places

For this project, you'll need five agar petri dishes, five disinfected swabs, sterilized water and a marker. It's important to keep the petri dishes in the fridge until you're ready to apply the swabs and then let them reach room temperature before starting the experiment. Label the petri dishes by location, according to the swab. Before swabbing a sample, dip the cotton swab in sterilized water so it will be damp. Take samples in five different locations around the house or outside of it. Try the bathroom door knob, a sink, a computer keyboard, the climbers at the park, the handle bar of a shopping cart, a wallet, an elevator button, a school door handle or any other high traffic area. Roll the swab on the agar in the petri dish and put on the cover. Repeat for each location. Keep the dishes in a cool place and then count the bacteria spots after five days and take pictures for the project. Display the results on a chart comparing the numbers. The sink or other damp location should have a higher number of cultures show up.

Is a Dog's Mouth Cleaner than a Human's Mouth?

This experiment requires four agar petri dishes, four cotton swabs, sterilized water and a marker. Keep the agar petri dishes in the fridge and then let them reach room temperature before applying the swabs. Label the petri dishes so you can keep track of the results. Dip a swab in sterilized water and then scrape it along the inside of your cheek. Roll the swab over the agar in the dish and cover. Repeat with a friend or adult. Next, obtain a sample using a swab in a dog's mouth and roll the swab over the agar. Younger children may need a parent to obtain the sample from the dog. Try it with a second dog if possible so the sample size is larger. Cover the dishes and store them in a cool place for five days. Open and count the spots the bacteria have formed. Show the results in the project using pictures and charts.

Which Part of the Hand is Hardest to Wash Germs Off?

This project uses Glo Germ, a material used to teach proper hand washing, which you can order online. You'll also need at least five volunteers, running water, an ultraviolet pen light and soap. Each person will need to rub a nickel-sized drop of Glo Germ onto the palm of their hands, spreading it all over the palm and fingers by rubbing their hands together. It's important to spread the Glo Germ all over the front and back of the hand, including between the fingers and on the fingernails. Ask your volunteer to wash his hands with soap and water as he normally would. After he's finished, look at his hands with the ultraviolet light. Any remaining Glo Germ will glow. You can check the hands in a darkened room if you're having trouble seeing the Glo Germ in normal light. Take notes on where the lights are showing. You can make a graph with different areas of the hand, such as fingernails, between fingers, palm and back of the hand, and whether each volunteer had Glo Germ showing there. To avoid embarrassing your volunteers, label their results by letter instead of name. Call the first volunteer "A" and the second "B".

Which Grows More Germs, Frequently Touched Items or Virtually Ignored Items?

This project explores whether the frequency of touch affects how many germs can be found in different areas. For this project, you'll need seven agar petri dishes, sterile swabs, sterilized water, bacitracin and a marker. Keep your agar petri dishes in the fridge and then let them reach room temperature before starting the experiment. Label the petri dishes by location. Start by dipping the cotton swab in sterilized water so it will be damp. Take three samples from areas that receive a lot of touch, like a telephone, television remote control, computer mouse or front door knob. After rubbing the damp swab on an item, roll the swab on the agar and then cover the dish. Next, find three areas that aren't touched as much, such as a fan, window sill, wall or a picture frame. Roll each swab on the agar as it's collected and then cover. As a control, roll a sample of bacitracin in the last petri dish. This will show you how much bacteria will grow over the eight day observation period without being influenced by germs collected. Leave all dishes covered and in a dark place for eight days. Using charts and photos, use your project to show which type of area has more bacteria and fungi. What impacts the results? Are frequently touched places cleaned more often?

About the Author

Darlene Peer has been writing, editing and proofreading for more than 10 years. Peer has written for magazines and contributed to a number of books. She has worked in various fields, from marketing to business analysis. Peer received her Bachelor of Arts in English from York University.

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