Area 10
Optics
Light rays, mirrors and lenses
Optics is about light: how it travels in straight lines, bounces off mirrors and bends when it passes into glass or water. Lenses and mirrors use these rules to form images in cameras, glasses and telescopes.
Who it suits
Children who like puzzles with angles and shadows, and anyone curious about glasses, cameras and rainbows.
What you will learn
- How light travels as rays and casts shadows
- How a mirror reflects light: the angle in equals the angle out
- Why light bends (refraction) when it passes into glass or water
- How lenses gather or spread light and form images
Example experiments
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Aim a light ray at a mirror and measure the angles before and after it bounces.
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Shine a ray into a glass block and watch how its direction changes.
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Move a lens along an optical bench and find where the image becomes sharp.
Things you can build
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A periscope with two mirrors
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A magnifying glass set-up
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A model camera with a lens and a screen
These examples show the kind of work in this area. The published lessons may differ.
What the simulation simplifies
- Light is treated mainly as rays (ray optics); wave effects such as interference and diffraction are beyond these lessons.
- Lenses and mirrors are ideal shapes; real lenses have flaws and can blur colours.
Every simulation simplifies reality. Knowing how it does so is part of learning engineering.
Links to school subjects
Physics (light), mathematics (angles and geometry), biology (the eye), art and photography
Connections to other areas
Optics links to electrical circuits (light sources and sensors), to structures and materials (glass and transparency) and to robotics (cameras and light sensors).
Good to know
Your eye has a lens too: it focuses light on the back of the eye, much as a camera lens focuses light on its sensor.