Year 9 Science · Unit 4 · Lesson 18
Challenge Worksheet
Learning Goals
Find the mistake
A student submitted the following investigation plan for "Does ramp angle affect car speed?" It has 5 data quality problems. For each problem: classify the type of error using the categories provided, and suggest a specific improvement.
Error categories: Validity error · Reliability error · Range error · Graph type error · Measurement precision error
| Problem in the student's plan | Error type | Suggested improvement |
|---|---|---|
| Only 1 trial was done at each angle | ||
| A carpet surface was used for one trial and a wood surface for another | ||
| Angle was measured with a protractor rounded to the nearest 10° | ||
| Only 2 angles were tested (10° and 20°) | ||
| A bar graph was drawn to display the data |
Design an original investigation
Design your own investigation into a wave OR motion phenomenon of your choice. Complete every box below. You must justify each decision with reference to working scientifically principles.
(a) Write a testable research question. It must involve a specific wave or motion variable you can measure in a school lab (e.g. wave speed, pendulum period, car acceleration, sound intensity). The question must be in the form "Does [IV] affect [DV]?"
(b) Identify all three variable types. For the DV: state exactly how you will measure it (instrument, units). For controlled variables: list at least three and explain why each must be kept constant.
| Independent variable | |
| Dependent variable (+ instrument & units) | |
| Controlled variable 1 + why | |
| Controlled variable 2 + why | |
| Controlled variable 3 + why |
(c) List your 5 IV values and explain why you chose this range. Then state how many trials you will run at each value and justify your choice using the concept of reliability.
(d) Justify why a line graph is appropriate for your investigation's data. What pattern do you expect? Sketch the shape of your expected graph in the box, with axes labelled.
Sketch your expected graph shape here. Label both axes with variable name and units.
(e) Identify one specific safety consideration for your investigation. Describe the hazard and the control measure you would use to manage it.
Wrap Up
In one sentence, what was the main idea of this lesson?