Year 8 Science · Unit 4 · Lesson 5
Apply Worksheet
Learning Goals
Find the mistake
A student's graph choice
"I investigated the germination rates of five different plant species (Grevillea, Wattle, Banksia, Kangaroo Paw, and Bottlebrush) after two weeks in identical conditions. I drew a line graph with the five species along the x-axis and germination rate (%) on the y-axis. I connected all five points with a single line."
(a) Why is a line graph the wrong choice for this investigation? Be specific about the type of data on the x-axis.
(b) What graph type should be used? Explain why it is more appropriate.
(c) List four features the correctly drawn graph must include.
Choose and justify
Two investigations, two different decisions
Investigation 1: A student measures heart rate (beats per minute) every 2 minutes during 20 minutes of exercise, then every 2 minutes for 10 minutes of recovery.
Investigation 2: A student measures the average height (cm) of bean plants grown with four different fertiliser types (Osmocote, Seasol, Powerfeed, no fertiliser) after 4 weeks.
For each investigation, complete the three response boxes.
| Question | Investigation 1: Heart rate over time | Investigation 2: Fertiliser type vs plant height |
|---|---|---|
| Best graph type | ||
| Justify your choice, why does this graph type suit this data? | ||
| List 4 required features for your graph |
1. Why does connecting categorical data points with a line give a misleading impression to the reader?
2. A student wants to show that 78% of air is nitrogen, 21% is oxygen, and 1% is other gases. Identify the best graph type and explain why it suits this data.
Wrap Up
In one sentence, what was the main idea of this lesson?