Year 8 - Science
Refracting light
Making images
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores the transmission of light, including absorption, scattering, and reflection, and the use of the ray model in imaging, refraction, and lenses. It also covers energy transfer in various processes, using safe techniques, making accurate observations, and improving reliability.
Lesson Summary
You will learn to describe and draw how a ray of light refracts when it moves from one medium to another, and explain how refraction can cause virtual images.
Key Notes
- Light changes direction when it moves into a new medium (material) at an angle to the normal. This is called refraction.
- When light enters a transparent material from air, it turns towards the normal.
- When light leaves a transparent material and re–enters air it turns away from the normal.
- A ray that enters and leaves glass through parallel sides ends up in its original direction, but displaced to the side.
- Refraction can cause virtual images of objects to appear where light seems to be coming from.
Vocabulary To Learn
- transmit: when light moves into and through a new medium
- medium: the material that light is travelling through
- refraction: when light changes direction when it enters a new medium
- normal: a line drawn at 90° to the surface of a material
- virtual image: a representation of an object seen where light appears to be coming from, not where light actually comes from
Common Mistakes To Avoid
- A ray of light curves as it passes through glass, perspex or water.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Light changes direction when it moves into a new medium (material) at an angle to the normal. This is called refraction. When light enters a transparent material from air, it turns towards the normal.
2. Define this scientific word and use it in context. 'transmit'
when light moves into and through a new medium. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: A ray of light curves as it passes through glass, perspex or water. Correction: Use a perspex block with the bottom painted white to demonstrate the path of a ray of light through it. Avoid putting too much emphasis on the term 'bending' light, instead try to primarily refer to light changing direction at a boundary.
More Lessons In This Unit
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