Year 9 Science · Unit 4 · Lesson 9
Challenge Worksheet
Learning Goals
Compare four light interactions
Complete the table to compare the four main types of light interaction. Fill in every blank cell — most rows require all four columns.
| Feature | Specular reflection | Diffuse reflection | Refraction | Absorption |
|---|---|---|---|---|
| What happens to the light ray | ||||
| Surface or material type required | ||||
| Can you see a clear image? | ||||
| Everyday Australian example | ||||
| A practical application |
Design a mini-experiment
A scientist wants to test: “Does the angle of reflection always equal the angle of incidence for a flat mirror?” Plan the investigation below.
| Aim | |
| Equipment (list at least 4 items) | |
| Method — write 5 clear steps | |
| Data table (draw a table to record 5 different angles of incidence and the measured angles of reflection) | |
| Expected result | |
| One source of error and how you would reduce it |
1. If your results showed that the angle of reflection was consistently 2° less than the angle of incidence, would this disprove the law of reflection? Explain whether this is more likely to be a real physical result or a measurement error, and how you could find out.
2. The Sydney Opera House tiles produce complex specular reflection patterns. Would a rough concrete wall in the same location produce specular or diffuse reflection? Explain the science and describe what you would observe in each case if you stood 5 metres away and shone a torch at the surface.
Wrap Up
In one sentence, what was the main idea of this lesson?