Reflecting light from mirrors
I can investigate the reflection of light from mirrors by tracing beams of light and measuring angles, and compare results to the known laws of reflection.
Reflecting light from mirrors
I can investigate the reflection of light from mirrors by tracing beams of light and measuring angles, and compare results to the known laws of reflection.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Light travelling in one direction (along a ray) that hits a mirror reflects (bounces off the mirror) in one direction.
- The ‘normal’ is an imaginary line drawn at 90° to the point of reflection.
- The angles of incidence and reflection are measured to the normal.
- The angle of reflection is always equal to the angle of incidence, the other side of the normal.
- On a graph, a line of best fit highlights the main pattern of the data, ignoring small errors.
Keywords
Protractor - a device used to measure angles
Normal - another way of saying ‘at 90°’ - a ‘normal line’ is at 90° to a surface
Reflect - to reflect off a surface means to hit the surface and ‘bounce’ off
Incident - an adjective meaning 'incoming'
Angle of incidence - the angle between the incident ray and the normal when light hits a mirror
Common misconception
Some pupils think that a ray of light can reflect off at an angle different to that at which it hits a plane mirror and perhaps in several directions.
Give pupils practical experience of measuring the angles at which light reflects off a plane mirror to confirm the correct rules; share results to confirm; and discuss potential sources of error that may lead to small discrepancies.
Equipment
Class practical: ray boxes (and power supplies if needed), suitable mirrors, protractors. Please see the additional materials for teacher and technician notes on this practical.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
Loading...
Starter quiz
6 Questions
Exit quiz
6 Questions
An imaginary line drawn at 90° to the point of reflection at a mirror.
An arrow showing the direction of light before it hits a mirror.
An arrow showing the direction of light after it hits a mirror.
