Year 8 Science · Unit 4 · Lesson 11
Challenge Worksheet
Learning Goals
Read the graph
The line graph below shows the height (cm) of pea seedlings over 30 days for three fertiliser types. Answer the three questions.
Data: simulated plant growth investigation, HSCScience Lab.
(a) Describe the trend for Fertiliser C. What is unusual about the growth pattern after day 20?
(b) At approximately what day do lines A and C cross over? What does this mean for comparing the two fertilisers?
(c) A farmer wants maximum crop height at day 30. Which fertiliser would you recommend based on the graph alone?
Using the graph on page 1, write a full extended CER argument answering the question: "Which fertiliser is best for commercial use?" Complete each scaffolded box.
Claim — Write one clear statement identifying the best fertiliser for commercial use and why.
Evidence — Quote three specific data values from the graph (include day and height) to support your claim.
Counter-evidence — Acknowledge one limitation or weakness of your chosen fertiliser shown in the data.
Reasoning — Explain scientifically why your chosen fertiliser performs the way it does. Use ideas about nutrients, photosynthesis, or plant cell biology.
Conclusion — Write one balanced sentence that states your recommendation while acknowledging the limitation you identified.
Wrap Up
In one sentence, what was the main idea of this lesson?