
Disinfectants and Bacteria Survival
Hard
Which household disinfectant kills the most types of bacteria? Products like Bleach and Lysol all claim to clean surfaces. This project puts four of them to a real test against six bacterial species.
You mix each disinfectant with bacteria in sterile tubes. After five minutes you spread the mixture onto agar plates and incubate overnight at 35 degrees Celsius. The next day you count surviving colonies on each plate.
The results show which product leaves the fewest living bacteria behind. One common household cleaner stood out above the rest.
Hypothesis
The hypothesis is that bleach will work the best in killing the bacteria.
Method & Materials
You will culture several species of bacteria, add disinfectant to the bacteria, spread the mixture on a nutrient agar plate, and incubate overnight.
You will need 40 microliters of each type of bacteria, 60 microliters of each type of disinfectant, 30 nutrient agar plates, 30 sterile loops, 30 sterile tubes, 1 pipette, and 1 incubator.
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See what’s includedResults
The results indicate that bleach worked the most effectively to kill bacteria. This stands out because it is an oxidant, which is a powerful disinfectant.
Why do this project?
This science project is interesting because it helps us to understand which disinfectant is the most effective in killing bacteria.
Also Consider
Variations to consider include testing different types of bacteria and testing different concentrations of disinfectant.
Full project details
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