Science Fair: Is a Dog’s Mouth Cleaner Than a Human’s Mouth?

UPDATE: My son took home 1st place at the district science fair with this project!! On to county we go!!

Does anyone else loathe science fair project time?? The experiment itself isn’t so bad; it’s all the other work that I hate: the research paper, the journaling everyday, putting the board together. It’s supposed to be a project for the kid, but let’s be real-it’s a project for the parents. If I let my nine-year-old do this completely by himself, his research paper would have three sentences (which would still take an hour for him to type, by the way) and his board would have a few words quickly scribbled in pencil (most likely sideways) with a few stick figures for illustration. Nope, this isn’t a project for kids. This is a project for mom and dad.

The teachers make sure to let us know that the kids need to be doing the work on this. Every year, I am tempted to just give my kids a go at doing it all on their own and let the teachers see how it turns out when the kid is really in charge. But at the end of the day, I don’t want my kid to be embarrassed when they share their boards with their peers, who will most likely have pinterest worthy boards that their moms spent all night finishing for them.

My husband is a great help when it comes to science fair projects. He loves the experimentation part of it and he helps to take the reins on that. This year we brainstormed lots of great ideas, but one idea stood out more than the rest. In fact, as we contemplated this topic, I had flashbacks of sitting beside my grandma in her car on a hot day, eating ice cream cones. Her poodle sat in her lap as we parked in the lot, licking our cones; grandma taking turns with her poodle to lick her cone. She always told us that a dog’s mouth is cleaner than a human’s and I decided that it was time to put her theory to the test. Time to bust this old myth!

To test our theory out, we used three human test subjects as well as three dog test subjects. We gave our dogs the advantage by choosing three kids for our subjects; surely kids, after Halloween, would produce a good amount of bacteria in their mouths! We bought petri dishes where we cultured the bacteria colonies. We are big fans of bacteria and petri dishes over here. I think this is our third bacteria project; they are fascinating! We swabbed each of our subject’s mouths and rubbed the swab inside a separate petri dish in a “z” pattern. We labeled each dish and put them in a dark place where the bacteria could breed for the next couple of days.

The results were disgusting! I am embarrassed to say that my youngest son had the most bacteria in his mouth (we need to work on that tooth brushing!!) Still, it was nothing compared to the bacteria that grew in the petri dishes belonging to the dogs. There were so many bacteria colonies, we couldn’t even count! Think twice before letting your dog lick you-or before sharing an ice cream cone!!

So I didn’t get too carried away with the board. I thought about getting letter stickers or cut-outs for the title, but then I thought better. I’m not so worried about having a winning project as much as I’m concerned about a good grade. I made Cody sit beside me and help. My OCD wouldn’t allow him to do the cutting, but he did glue all of the labels onto the cardstock. I only had to fix a few. He did choose the colors and he may have done a tiny bit of typing, so I’d say this was definitely his project!

The project is done, and tonight I can go to bed at a decent hour!

If you’d like to do this project, you can find the petri dishes here. The full instructions on how to use the dishes and culture the bacteria are included. It’s really simple and makes for an interesting experiment!

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