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Madeline's Science Project, 6th Grade


Awards Earned:

2nd Place, 6th Life Science, PCA Science Fair
2nd Place, 6th Life Science, ACSI Regional Science Fair

Photograph of Madeline's Science Project
Problem to be Solved:

Do canines or humans have more bacteria in their mouths?


Canines will have more bacteria in their mouths for several reasons such as the way they take a bath, what they eat, and lack of brushing their teeth.


1] Black Labrador mix, female, 12 years old.
2] Golden Retriever, male, 6 years old.
3] Shitzu, male, 2 years old.

1] Causasian, female, 11 years old.
2] Caucasian, male, 12 years old.
3] Asian, female, 12 years old.


1] Prepare agar and pour in marked petri dishes.
2] Swab dogs and humans mouths using sterile swabs. Swab around teeth and gums for ten seconds each. Swab between 3:40 and 5:00 P.M. so that it has been at least two hours after food has been in the mouth.
3] Lightly brush the swab over marked area of petri dish.
4] Keep petri dishes in a warm area at around 21 degrees C.
5] Record bacteria growth in petri dishes after any change has been noticed.
6] Compare bacteria growth from canines and humans.


The hypothesis that canines would have more bacteria in their mouths was correct. There was more bacteria growing in the canine petri dishes than in the human petri dishes.  This proves that the old wife's tale that says that a dog's mouth is cleaner than a human's mouth is incorrect. The one quiestion I have left is, "What kind of bacteria is in the marked area of each petri dish?"

Biblical Application:

God saw all that He had made, and it was very good (Genesis 1:31a). When God created the Earth, it and everything in it was perfect. Harmful bacteria did not exist.

Nevertheless, death reigned from the time of Adam to the time of Moses, even over those who did not sin by breaking a command, as did Adam, who was a pattern of the one to come (Romans 5:14). When Adam and Eve sinned, God punished all humans by taking away perfect health and giving us death. People, from the time of Adam to the present age, can die from many diseases. Diseases can be caused by harmful bacteria.

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