A student investigated the effect of temperature on the decay of milk - AQA - GCSE Biology - Question 9 - 2021 - Paper 1
Question 9
A student investigated the effect of temperature on the decay of milk. Figure 15 shows the apparatus the student used.
This is the method used.
1. Set up the appara... show full transcript
Worked Solution & Example Answer:A student investigated the effect of temperature on the decay of milk - AQA - GCSE Biology - Question 9 - 2021 - Paper 1
Step 1
How could the student keep the milk at a constant temperature for 5 days?
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Answer
The student could maintain the milk at a constant temperature by using a water bath. This method ensures that the milk is submerged in a controlled environment, which minimizes temperature fluctuations.
Step 2
Give one variable the student should keep constant.
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Answer
One variable the student should keep constant is the type of milk used in the experiments, as different types may decay at different rates.
Step 3
Complete Figure 16.
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Answer
For Figure 16, label the x-axis as 'Days' and ensure it has a suitable scale with marks at least 1 cm apart. Plot the pH data from Table 2 accurately for each day. Finally, draw a smooth curve that best fits the plotted points, representing the trend in pH over the days.
Step 4
Sketch a line on Figure 16 to show the results you would expect at 25 °C.
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Sketch a line similar in shape to the one plotted for 20 °C, which should begin at the same starting pH but will generally be higher than the 20 °C curve after 5 days, indicating a different decay rate. Label this line '25 °C'.
