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.
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.
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.
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
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).
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.
