Well, when one has a science project, it usually means that another one does too. Taya & Bladen both had to prepare a project for the Elementary School Science Fair this year. Both wanted to do something with bacteria so it worked out perfectly. Taya's was quite interesting.
She wanted to see if the "5 second rule" really was true. Does food really NOT pick up bacteria in 5 short seconds? Or does it?
First she picked 3 types of foods to try out:
a piece of bread
a sucker (wet with bottled water so it would be slightly sticky)
& chicken nuggets
Next she picked 3 locations/floors to test out:
our kitchen floor,
the floor of McDonalds,
& the floor/ground where the kids eat lunch at her school.
The first thing she did was swab each of the foods before putting them on the floor so she could see if they contained any bacteria to begin with. Then she tested each of the floors to see what bacteria grows naturally there.
Then she did her real experiment by dropped each food item at each location for 5 seconds each, then swabbing them for bacteria after the 5 seconds was up. She used 15 petri dishes to complete the experiment.
It takes 48 hours for bacteria to grow, so she put her petri dishes in a closet with a space heater set to 87 degrees for 48 hours. We were AMAZED at what we learned.
Sure enough, the sucker, bread, & chicken nuggets alone (before putting on the ground) had NO bacteria on them. All 3 petri dishes were clean, even after 48 hours.
And the ground swabs were gross. Even my kitchen floor had bacteria, even though I sweep & mop it regularly. Our house floor & the McDonald's floor were equal in grossness. But the biggest surprise was how disgusting the ground was where the kids eat lunch at school. The SMELL!!! Oh my heavens. It was beyond DISGUSTING.
The results of the actual experiment was interesting. The bread acted like a sponge & picked up bacteria from all 3 locations, even after 5 seconds. The more bacteria on the ground, the more it soaked up, so the school ground was the worst with the bread.
Surprisingly, the chicken nugget picked up VERY little bacteria in all 3 locations, including the dirty lunch table ground. The hardness of the nugget probably prevents it from soaking up much.
And REALLY surprisingly, the wet sucker (which we thought would be compltely sticky & pick up everything) didn't pick up much at all. Again, the dirtier the ground, the more bacteria was picked up.
The smell from all these dishes were awful. . . mostly due to the lunch table petri dish. The stench was literally gag inducing.
Then it was time for her to put all her results together on her science board.
Her conclusion was that the dirtier the ground, the more bacteria will be picked up by your food. Spongy or soft foods will most likely pick up more bacteria than hard foods.
I can't even tell you how many times my kids have dropped SANDWICHES on the ground & then picked them up & ate them. It makes me gag just thinking about it. It's amazing that that has more bacteria that a sticky sucker!!!!
Taya worked SO hard on her poster. She typed everything up & arranged it SO nicely on her board. I was very proud of her work. She's a perfectionist like her big sisters.