Reflected images
I can describe and explain the properties of reflections in a plane mirror, and draw diagrams to show how reflections form.
Reflected images
I can describe and explain the properties of reflections in a plane mirror, and draw diagrams to show how reflections form.
Lesson details
Key learning points
- Reflections are the same size as the object, upright, and the same distance behind the mirror as the object is in front.
- In a plane mirror, reflections appear laterally inverted compared to the object when it is facing us.
- Mirrors reflect what is in front of them. Reflections are laterally inverted as objects are turned to face a mirror.
- Reflections are virtual images; they appear where light rays seem to have come from, not where they actually come from.
- Virtual rays show where light rays appear to have come from; they are drawn as dashed lines.
Keywords
Image - a representation of an object
Reflection - (1) the process of light ‘bouncing off’ a surface (2) an image seen in a mirror
Laterally inverted - describes an image that has been ‘flipped’ horizontally
Virtual ray - a dashed line drawn to show where light seems to be (but is not actually) coming from
Virtual image - an image that can be seen but not projected onto a screen
Common misconception
Mirrors must somehow turn images around or ‘flip’ them to make reflections laterally inverted.
Explicitly teach that a mirror merely (and passively) reflects what is directly in front of each part of it. Pupils can observe the reflection of text on clear plastic: the image is the same as what is seen looking through the back of the text.
Equipment
Teachers could consider making mirrors, clear plastic and pens (for writing on clear plastic) available for use this lesson to demonstrate some of the ideas covered.
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
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