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A group of students wanted to test whether water purifying tablets were effective in making creek water free from bacteria - HSC - SSCE Biology - Question 25 - 2015 - Paper 1
Question 25
A group of students wanted to test whether water purifying tablets were effective in making creek water free from bacteria. They conducted an experiment using a wat... show full transcript
Worked Solution & Example Answer:A group of students wanted to test whether water purifying tablets were effective in making creek water free from bacteria - HSC - SSCE Biology - Question 25 - 2015 - Paper 1
Step 1
Describe a means of addressing ONE identified hazard relevant to this investigation.
Answer
One identified hazard in this investigation is the potential presence of harmful bacteria in the creek water. To address this hazard, the students should wear appropriate personal protective equipment (PPE) such as gloves and masks while handling the water samples. This will help prevent contamination and protect the students from any pathogens that may be present in the water, ensuring safe handling during the experiment.
Step 2
Illustrate the results of this experiment in diagrammatic form.
Answer
To illustrate the results of the experiment, a bar chart can be used. The x-axis can represent the different conditions: 'Treated Water' and 'Untreated Water,' while the y-axis can indicate the level of bacterial contamination (e.g., CFU per mL).
- Treated Water: Bar height shows a significantly lower bacterial count, indicating effective purification.
- Untreated Water: Bar height shows much higher bacterial count, confirming the presence of bacteria.
This diagram can be clearly labeled to indicate the bacterial counts, and a title such as 'Effectiveness of Water Purifying Tablets' can be added for clarity.