Looking for a science experiment you can do at home with just a few materials? Why not test to see if a dog or human mouth is cleaner?
Whose Mouth Is Cleaner: Human or Dog?
This experiment is really easy, and a lot of fun! My daughters loved it so much that we are now planning to test how dirty all sorts of things are compared to our dogs’ mouths.
What You Need For This Science Experiment
You don’t need a lot to do this science experiment at home! The most important thing is Agar Plates. You can, of course, create your own with Petri dishes and agar solution, but I found buying this Science experiment kit on Amazon was the best option.
You will also need an incubator, or, you can create your own out of household items. This is what we used.
- Science Fair Experiment Kit – comes with agar plates, sterile cotton swabs, and directions.
- saran plastic wrap
- Tupperware large enough to hold the Petri dishes side by side
- desk lamp with non-LED bulb
- sharpie marker
- scotch tape
- bottled water
- portable thermometer
How To Perform This Experiment
STEP ONE: Using the Sharpie marker, label agar plates with names of all participants (humans and dogs). Carefully open the Agar plate, avoiding contaminating the dish. Be sure it is label side down, and the cover is close by.
STEP TWO: Open the cotton swabs and remove one. Dip it in some bottled water – DO NOT USE TAP WATER OR YOU CAN CONTAMINATE THE EXPERIMENT. Swab mouth, being sure to turn the swab 360 degrees inside the mouth.
STEP THREE: Immediately rub the swab in the center of the Agar plate, being careful not to press too hard. Roll the swab around 360 degrees and then spread out from the center like a sun. Then, roll the swab and fill in the spots in between the lines. Put the cover on your Agar plate.
STEP FOUR: Carefully tape the plate shut with scotch tape. Place Agar plates side by side in a Tupperware with the thermometer so you can monitor the temperature.
STEP FIVE: Repeat steps 2–4 using a separate, fresh cotton swab for each participant.
STEP SIX: Once all sealed agar plates are in the Tupperware container, cover the whole container in Saran plastic wrap.
STEP SEVEN: Place sealed Tupperware container under desk lamp. If you use an LED bulb the incubator will not get hot enough (I learned this the hard way). Keep between 80 and 100 degrees for 4–5 days. Too low or high and the bacteria could die. Condensation in the incubator is normal. After about 24 hours, you should start to see some growth.
STEP EIGHT: To determine results, look at the thickness of the lines of bacteria. The thicker the lines, the dirtier the mouth. The thinner the lines, the cleaner the mouth.
Conclusion: How did you compare to your dog?
Download printable experiment directions here: TLAD-Science-Experiment
About Think Like A Dog
Dogs Best Friend is about a 12-year-old tech prodigy whose science experiment goes awry and he forges a telepathic connection with his best friend, his dog. The duo join forces and use their unique perspectives on life to comically overcome complications of family and school.
THINK LIKE A DOG is available on Digital, On Demand, Blu-ray, and DVD June 9!
