Year 7 Science · Unit 4 · Lesson 6
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Learning Goals
Sort the variables
A class in Newcastle tests this question: does the height of a ramp affect how far a toy car rolls? For each item below, write whether it is the independent variable, the dependent variable, or a controlled variable.
| Item in the investigation | Type of variable |
|---|---|
| The height the ramp is set to (10 cm, 20 cm, 30 cm, 40 cm) | |
| The distance the car rolls after the ramp | |
| Using the same toy car every time | |
| Using the same smooth floor every time |
Real-world context
A Year 7 group in Newcastle rolled the same toy car down a ramp four times, raising the ramp a little higher each time. They kept the car, the floor and the starting point the same. They measured how far the car rolled past the bottom of the ramp and wrote the results in this table.
| Ramp height (cm) | Distance rolled (cm) |
|---|---|
| 10 | 30 |
| 20 | 55 |
| 30 | 75 |
| 40 | 95 |
(a) If you drew a line graph of this data, which variable would go on the bottom (horizontal) axis, and which would go up the side (vertical) axis?
(b) Describe the trend shown by the data. Is the distance increasing, decreasing or staying the same as the ramp gets higher?
(c) Write a conclusion for this investigation. Answer the question and use two numbers from the table as evidence.
1. The group rolled the car at each ramp height three times and worked out an average each time. Why is repeating the measurement a good idea?
2. Suppose a classmate used a different, heavier car halfway through the test. Explain why this would make the test unfair and the conclusion harder to trust.
Wrap Up
In one sentence, what was the main idea of this lesson?