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General Medicine & Health Science Fair Project

Is a dog's mouth cleaner than a human's?

Is a dog's mouth cleaner than a human's? | Science Fair Projects | STEM Projects
Ever wondered who has more bacteria in their mouth, dogs or humans? In this science project, you'll swab the mouths of dogs and humans and compare the bacteria growth in petri dishes.


The hypothesis is that dogs will have more bacteria in their mouths.

Method & Materials

You will swab the mouths of dogs and humans, lightly brush the swab over marked area of petri dish, and keep petri dishes in a warm area.
You will need agar, petri dishes, sterile swabs, and a thermometer.


The hypothesis was correct - dogs had more bacteria in their mouths than humans. This proves that the old wife's tale that says that a dog's mouth is cleaner than a human's mouth is incorrect.

Why do this project?

This science project is interesting because it tests an old wives' tale and provides evidence to prove it wrong.

Also Consider

Variations to consider include testing different breeds of dogs and humans, testing different ages of dogs and humans, and testing different times of day.

Full project details

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