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Molecular Biology Science Fair Project

Bacteria and Toothpaste

Bacteria and Toothpaste | Science Fair Projects | STEM Projects
Let's see if brushing your teeth with toothpaste can reduce the amount of bacteria in your mouth. We'll measure the size of the bacteria colony before and after brushing with different types of toothpaste.


The hypothesis is that the amount of bacteria in your mouth will be reduced after brushing your teeth with toothpaste.

Method & Materials

You will prepare 8 agar petri dishes, use a disinfected swab to take samples from the participant's mouth, brush the teeth with 4 different types of toothpaste, and measure the size of the bacteria colony after 5 days.
You will need 8 agar petri dishes, 8 disinfected swabs, 1 bottle of disinfected water, 4 toothbrushes, 1 participant, 1 cup and water, 4 types of toothpaste, and 1 marker pen.


The results showed that all the petri dishes with bacteria samples taken after brushing with toothpaste had a smaller amount of bacteria growth. The petri dish with Colgate toothpaste had the smallest sized bacteria colony.

Why do this project?

This science project is interesting because it shows how toothpaste can help reduce the amount of bacteria in your mouth and help keep your teeth healthy.

Also Consider

Variations: This science project may be repeated, this time, with swab sample from different locations in the mouth like the tongue. Modify the science project experiment, using different brands of mouthwash.

Full project details

You can find additional information and details for this science fair project here. Have fun exploring!

Related videos

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