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Extreme temperatures and its effect on the growth of bacteriaFeatured science projectScience project video


The purpose of this experiment is to investigate if extreme temperatures kill bacteria more effectively, especially so if the bacteria is exposed to extremely high temperatures (as opposed to extremely low temperatures).


Extremely high temperatures will kill more bacteria extremely low temperatures.

Scientific Terms

Bacillus Cereus, Clostridium Perfringens, Mycobacterium Tuberculosis, Salmonella, Bacteria Cultivation, Denaturation, Protein Structure


Nature of Bacteria

Bacteria are single-celled living organelles. This means they are self-sustaining life forms, able to metabolize and reproduce. To facilitate the biological functions of the bacteria, they contain carboxysomes. Carboxysomes are protein based structures containing enzymes.

As such, knowing the nature of bacteria leads us to understand the effect heat has on bacteria.  Being mainly protein-based, bacteria undergo denaturation when it is exposed to extreme heat, acid and hydrolysis. This means the proteins lose their cellular shapes, lose cell activity and this eventually leads to cell death.

An alternative for killing bacteria

Vinegar, widely known for its powerful antibacterial property, is a traditional cleaning agent and it works just as well or even better than common disinfectants.

How do I use vinegar for cleaning purposes?

An easy way to keep the multi-functional vinegar at hand is to have a bottle of pure 5% vinegar near your cutting board or in your bathroom and spray it onto any surface you wish to clean and disinfect. Vinegar gives out a strong smell once exposed to air. However, it disappears within hours.

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Complexity level:
Project cost ($):
Time required:
2 hours to prepare (Day 0), 7 days incubation period (Day 1 to Day 7), 15 minutes each day (from Day 1 to Day 7), 30 minutes to transfer samples on Petri Dish (Day 8) 24 hours for inoculation, Observation on Day 9
Material availability:
The school biology laboratory should provide all the necessary materials.
Safety concerns:

Goggles and gloves must be worn at all times to prevent contamination as we’re dealing with biohazardous materials. Adult supervision encouraged.