Year 7 Science · Unit 3 · Lesson 5
Challenge Worksheet
Learning Goals
Design a mini-experiment
A scientist wants to test: "Does the mass of an object affect how far it slides along a flat surface after a pushing force is removed?" Plan a fair test investigation below.
| What I will change (independent variable) | |
| What I will keep the same (controlled variables — list at least 3) | |
| What I will measure (dependent variable) | |
| My prediction (using Newton's First Law and inertia) | |
| How I would know if my prediction is wrong | |
| One limitation of this experiment |
1. NASA's Voyager 1 spacecraft (launched 1977) is currently travelling through interstellar space at about 17 km/s, with its engines off. Its speed has barely changed in decades. Explain this using Newton's First Law. In your answer, name the forces that would be needed to change Voyager's speed and explain why they are almost absent in deep space.
2. The "tablecloth trick" — pulling a cloth quickly from under dishes — relies on inertia. Explain why the trick works when the cloth is pulled fast but fails when pulled slowly. Use the terms "inertia," "unbalanced force," and "time" in your answer.
Wrap Up
In one sentence, what was the main idea of this lesson?