
Bacteria Survival at Extreme Temperatures
Hard
Can bacteria survive boiling water or dry ice? You expose three species -- E. coli, Streptococcus, and Bacillus -- to five temperatures. These range from -78 degrees Celsius (dry ice) up to 100 degrees Celsius (boiling).
Each sample sits at its assigned temperature for two hours. Then you transfer the bacteria to agar Petri dishes and wait five days.
Bacteria exposed to 60 and 100 degrees Celsius show no growth at all. Bacteria held at -78 and 0 degrees Celsius still grow normally.
Hypothesis
The hypothesis is that bacteria will be deactivated and destroyed at temperatures above 60 degrees Celsius.
Method & Materials
You will divide the Petri dishes and test tubes into three groups, label them according to the species of bacteria, and place them in beakers with different temperatures. After two hours, you will swab the test tubes onto the Petri dishes and incubate them for five days.
You will need 15 agar Petri dishes, 15 disinfected swabs, a bottle of disinfected water, 15 test tubes and a rack, a measuring cylinder, 50 ml E Coil bacteria culture, 50 ml Streptococcus bacteria culture, 50 ml Bacillus bacteria culture, a marker pen, 5 beakers, 2 hot plates, 3 thermometers, a bag of ice, a bag of dry ice, and a clock.
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See what’s includedResults
The results showed that the high temperatures of 60 degrees Celsius and 100 degrees Celsius destroyed the bacteria, while the lower temperatures of -78 degrees Celsius and 0 degrees Celsius were still within the optimal range of temperatures for bacteria growth. The control group, which was left at room temperature, showed significant growth.
Why do this project?
This science project is interesting because it explores how temperature affects the growth of bacteria, which is an important factor in understanding how bacteria can spread diseases and cause people to become ill.
Also Consider
Variations of this project could include repeating the experiment with different temperatures and species of bacteria, such as Staphylococcus or Campylobacter.
Full project details
Additional information and source material for this project are available below.Related videos
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