Year 8 Science · Unit 4 · Lesson 15
Challenge Worksheet
Learning Goals
Read the graph
Enzyme activity at five temperatures — student depth study data
Data: student investigation, school laboratory, 2026.
(a) Describe the overall trend in enzyme activity as temperature increases from 20 °C to 60 °C. Use data values in your response.
(b) Calculate the percentage decrease in enzyme activity from the peak (37 °C) to 60 °C. Show your working.
(c) Write a CER conclusion for this data. Your Claim should state the optimal temperature; your Evidence should quote at least two values from the graph; your Reasoning should explain the trend using what you know about how temperature affects chemical reactions.
Find the mistake
A student's investigation report
"The dependent variable was the temperature, which was set at 20, 30, 37, 45 and 60 °C. To show the trend over these continuous temperature values, I drew a bar graph. The outlier at 45 °C — which was much lower than the peak — was deleted from the results to make the graph look cleaner. Accuracy was improved by conducting three trials at each temperature. In conclusion, the experiment was successful and showed that enzymes work better at higher temperatures."
The report contains five errors spanning the whole unit. For each error, identify it, classify the type of mistake, and write the correct version.
| Error (quote from the report) | Type of error | Corrected version |
|---|---|---|
| "The dependent variable was the temperature." | ||
| "I drew a bar graph to show the trend over continuous temperature values." | ||
| "The outlier at 45 °C was deleted from the results." | ||
| "Accuracy was improved by conducting three trials." | ||
| "In conclusion, the experiment was successful." |
Wrap Up
What is the most important working scientifically skill you have developed in Unit 4, and why?