Year 7 Science · Unit 3 · Lesson 8
Apply Worksheet
Learning Goals
Compare two
Complete the table to compare snowshoes and stiletto heels. Fill in both columns for each feature using information from the lesson.
| Feature | Snowshoes | Stiletto heels |
|---|---|---|
| Force applied to the ground (force from the person's weight) | ||
| Contact area with the ground surface | ||
| Pressure created on the surface (high / medium / low) | ||
| Best suited environment and why | ||
| Risk of sinking into a soft surface (e.g. snow or soft lawn) |
Scenario
A 70 kg person walks across an old wooden deck in a backyard in Melbourne. The deck has some planks that are soft and slightly rotten. At one point, the person stops walking. In the first situation, they are standing on both feet (with runners). In the second situation, they shift their weight onto just one foot — the same body weight, now on half the contact area.
(a) Predict: In which situation is the plank more likely to crack or break under the person — standing on two feet, or balancing on one foot? Write your prediction clearly.
(b) Justify your prediction using the scientific ideas about pressure, force, and area from this lesson. Mention what stays the same and what changes between the two situations.
1. Farm tractors in Australia use very wide tyres. Explain why, using the concept of pressure. What problem would narrow tyres cause for the crops in the field?
2. Dams in Australia (such as the Warragamba Dam in NSW) are built with walls that are much thicker at the base than at the top. Explain why engineers design dams this way, using the idea of how pressure in water changes with depth.
Wrap Up
In one sentence, what was the main idea of this lesson?