The 5 Second Rule
Which type of food
will grow the most
being dropped on
the ground for 5
We found our
I went onto Google.com and
looked up experiments
clicked on the link to
Education.com and found
the five second rule.
Bacteria will spread on
the piece of food and
contaminate it. Not so
much that you can’t eat
it but will spread
● Food items to be tested (e.g., wet
item like lunch meat and dry item
like a jelly bean). You will need six
of each item tested.
● Sterile swabs
● Sterile gloves
● Prepared nutrient agar in sterile
● Notebook to record results
1. Prepare 12 sterile plates containing nutrient agar.
2. Put on sterile gloves (do not touch any non-sterile surface
when wearing gloves).
3. Select two types of “ground."
4. Drop the first test item (e.g., a piece of lunch meat) on the
first type of ground.
5. Start the timer.
6. Remove the item from the ground after five seconds.
7. Swab the item with a sterile swab (do not touch anything
else with the swab).
8. Remove the top of the petri dish. Keep the top of the dish
in your hand away from any non-sterile surface.
9. Gently run the swab back and forth in a zigzag pattern on
the surface of the agar plate. Do not touch any part of the
10. Put the top of the petri dish back on and label.
11. Change your gloves.
12. Repeat the test with the first item (e.g., a new piece of
13. Repeat the test twice with the second item (e.g., two
separate jelly beans).
14. Change types of ground and perform the test twice with
15. Swab items that have not been dropped on any ground.
Create 2 “control” agar plates for each item tested.
16. Place the petri dishes in an environment that is as close
to 37ºC as possible. Bacteria will take longer to grow at
room temperature. Ensure that all petri dishes are placed
in the same location.
Results Our experiment was a
success. It was a cracker
that had the most bacteria.
We thought that the cheese
would have grown the most.
The experiment was fun to
In conclusion this is a great experiment that any 5th grader would be
happy to do. It does get a bit gross but is also super cool. When you
see what has grown on the foods you will be surprised on how you
might have thought that the most bacteria would grow on one food
and may grow on another. So, this experiment was a total success
and we suggest you to try it out yourself.
1.Which mouth has more bacteria a Mini Rex rabbit, a
bearded dragon lizard, Sulcata tortoise or a human?
2. We found our sources by Mrs. Abernathy.
3. We think that Thunder will have the most bacteria in his
4. Sterile gloves, Sterile glove and
Prepared nutrient agar in sterile plates
5. Take 4 cotton swabs and place them in each of the
mouths. Prepare the nutrient agar in sterile plates.
Animal v. Human
5.After you have swabbed the mouths place each
of the cotton swabs into a petri dish and keep in a
cool dark spot for 5-9 days.
6. The results are that Thurman the Sulcata
tortoise had the most bacteria on his swab which
surprised us all.
7. In conclusion we were so so surprised that
Thurman had the most bacteria in his mouth. We
are very glad that we did this experiment.