A different student repeated steps 1 to 5 of the method four times using 0.50 g of zinc powder.
Table 2 shows the results.
<br/><br/>
<table border="1" cellpadding="12" cellspacing="0" style="border-collapse: collapse; font-family: Arial, sans-serif; font-size: 15px; border: 2px solid black;"> <caption style="font-weight: bold; font-size: 18px; margin-bottom: 10px;">Table 2</caption> <tr> <th style="border: 1px solid black; padding: 12px;"></th> <th style="border: 1px solid black; padding: 12px; text-align: center; font-weight: bold;">Trial 1</th> <th style="border: 1px solid black; padding: 12px; text-align: center; font-weight: bold;">Trial 2</th> <th style="border: 1px solid black; padding: 12px; text-align: center; font-weight: bold;">Trial 3</th> <th style="border: 1px solid black; padding: 12px; text-align: center; font-weight: bold;">Trial 4</th> </tr> <tr> <td style="border: 1px solid black; padding: 12px; font-weight: bold;">Highest temperature reached in °C</td> <td style="border: 1px solid black; padding: 12px; text-align: center;">37.6</td> <td style="border: 1px solid black; padding: 12px; text-align: center;">37.2</td> <td style="border: 1px solid black; padding: 12px; text-align: center;">37.8</td> <td style="border: 1px solid black; padding: 12px; text-align: center;">37.4</td> </tr> </table> <br/><br/>
Calculate the mean highest temperature reached.
Include the uncertainty in your answer.

How to approach this question

1. **Calculate the mean:** Add all the temperature values together and divide by the number of values (which is 4). 2. **Calculate the range:** Find the difference between the highest and lowest temperature values. 3. **Calculate the uncertainty:** The uncertainty is half the range. 4. **Write the final answer:** State the mean followed by the ± symbol and the uncertainty value.

Full Answer

**1. Calculate the mean:** The mean is the sum of the values divided by the count of the values. Mean = (37.6 + 37.2 + 37.8 + 37.4) / 4 Mean = 149.0 / 4 Mean = 37.5 °C **2. Calculate the uncertainty:** Uncertainty in a set of repeat measurements is calculated as half the range. Range = Highest value - Lowest value Range = 37.8 - 37.2 = 0.6 °C Uncertainty = Range / 2 Uncertainty = 0.6 / 2 = 0.3 °C **3. Combine the results:** The result is written as the mean ± uncertainty. Mean highest temperature = 37.5 ± 0.3 °C

Common mistakes

✗ Forgetting to calculate the uncertainty. ✗ Calculating the range but not halving it for the uncertainty. ✗ Rounding the mean incorrectly.

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