Exploring the Future Potential of AI-Enabled Smartphone Processors
Temp. vs. Bact G4 - Group 25
1. Temperature vs. Bacteria Independent Variable Temperature (Hot Water Bath) Dependent Variable Amount of bacteria, presence of coliform bacteria Controlled Variable Amount of water (20mL) Amount of time heated (2min) Incubator Temperature (35/40 degrees Celsius) Amount of water used for coliform test (1mL) RESEARCH QUESTION AT WHAT TEMPERATURE WILL THE BACTERIA FROM POND WATER BE KILLED? HYPOTHESIS As temperatures increase the amount of bacteria decreases thus by boiling point (100°C) all bacteria that are harmful to humans will be killed. Alan Wu, Robert Lee, Jason Woo & Janita Zhang
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3. Procedure – Prior to Main ExperimentCollect sample of pond water and cultivate bacteria Procedure – Main Experiment Place test tubes of distilled water in hot water bath Adjust to desired temperature (lowest to highest temperature) Temperature reached – add bacteria from agar plates into the test tube, leave in for 2min. Agar Plates & Coliform Test
Reason for using coliform bacteria as an indicator is because it is usually from a similar source as pathogens (i.e. fecal contamination usually contains both coliform bacteria and pathogens). Coliform is easier to identify, and finding pathogens in a sample is often troublesome, unfeasible, and may even be hazardous. So coliform testing is a reasonable indication for whether pathogens exist or not. Total coliform bacteria count is often used as a primary indicator for water contamination.
Agar plates showed inconsistent results because they all showed growth of bacteria. However, the coliform tube tests showed a gradual colour change from lower temperatures to higher temperatures, the liquid in the lower temperatures changed to a yellow/greenish colour and the higher temperatures maintained the purple colour displaying that coliform bacteria does not exist. Since the presence of coliform bacteria is a good indicator of pathogens (bacteria that is harmful to humans), the bacteria present in the agar plates of higher temperatures is possibly bacteria that is not harmful to humans. Since the agar plates did not narrow down to cultivating a specific bacteria, all kinds of bacteria, whether harmful or not to humans, could grow on the agar plates thus the agar plates support that not all bacteria can be killed at high temperatures, however, according to the Wilderness Medical Society, water temperatures above 70° C kill all pathogens within 30 minutes and above 85° Cwithin a few minutes. So in the time it takes for the water to reach the boiling point (100° C) from 70° C, all pathogens will be killed. Of the majority of the coliform results, this can be supported. The first test tube that stays purple lands on the test tube of 70° C. Comparing the results from 40° C-65° C and 70° C-100° C it is significant that coliform bacteria is certainly present in the lower temperatures and not present in the majority of the higher temperatures.
Since the presence of coliform bacteria is a good indicator of pathogens (bacteria that is harmful to humans), the bacteria present in the agar plates of higher temperatures is possibly bacteria that is not harmful to humans. Since the agar plates did not narrow down to cultivating a specific bacteria, all kinds of bacteria, whether harmful or not to humans, could grow on the agar plates thus the agar plates support that not all bacteria can be killed at high temperatures, however, according to the Wilderness Medical Society, water temperatures above 70° C kill all pathogens within 30 minutes and above 85° Cwithin a few minutes. So in the time it takes for the water to reach the boiling point (100° C) from 70° C, all pathogens will be killed. Of the majority of the coliform results, this can be supported. The first test tube that stays purple lands on the test tube of 70° C. Comparing the results from 40° C-65° C and 70° C-100° C it is significant that coliform bacteria is certainly present in the lower temperatures and not present in the majority of the higher temperatures.
Errors Higher temperatures hard to control because evaporation of heat (large uncertainty)Possible risk that lids can cause contamination (high temperatures)Amount of time at each temperature (according to the Wilderness Medical Society, water temperatures above 70° C kill all pathogens within 30 minutes and above 85° Cwithin a few minutes)Agar Plates – air contaminationConclusionTo answer our experimental questions, based on our experimental results and research all bacteria from pond water will not be killed even when the water is boiled to 100 degrees. But however, local villagers only need to boil water to 70 degrees for 5 minutes, since this shows no more coliform bacteria from our experiments. Bacteria that is present in water when it’s boiled past the 70 degree mark is, according to the coliform test results, not harmful to humans. Therefore boiling water to 70 degrees will be sufficient.
