Year 8 Science · Unit 4 · Lesson 7
Challenge Worksheet
Learning Goals
Read the graph
Study the bar chart below showing dissolving time at five temperatures. Answer the three questions that follow.
* Orange bar = suspected outlier. Data based on a typical Year 8 class investigation, 2025.
(a) On the chart above, draw a dashed line showing the expected trend if the 60°C result followed the pattern of the other four temperatures. Describe the overall trend using the lesson sentence structure: "As temperature increases from ___ to ___, dissolving time ___."
(b) Identify the outlier and suggest two possible causes — one that is a measurement/recording error and one that could be a genuine scientific reason.
(c) The four non-outlier results at 20–50°C give an average dissolving time of (85+62+41+24)÷4 = 53 s. If the 60°C result were excluded from the full five-trial average, calculate what the new average would be. Show your working.
Ethical dilemma
After plotting their results, a student notices the 60°C bar "ruins" the smooth downward trend they expected. They are tempted to simply delete the result from their table before submitting, reasoning that it was "probably a mistake anyway." Their teacher has not yet seen the raw data.
(a) Explain why deleting the 60°C result without any investigation or acknowledgement is scientific misconduct. What makes it different from legitimately excluding a data point?
(b) How do peer review and replication protect science against data manipulation? Explain each process and why both are needed.
(c) Describe a real-world example where data manipulation or concealment in science caused serious harm to people or the environment. Identify what was done wrong and what the consequences were.
Wrap Up
In one sentence, what was the main idea of this lesson?