Page 139 - Knowledge Organiser Yr8 24-25

Knowledge Base: Science 8.7 Electromagnetic Waves Year 8
3. Shiny and Dull Materials
3.1
What is specular reflection?
When all of the light hitting an object is reflected off a surface at the same angle.
3.2
What is diffuse reflection?
When all of the light hitting an object is reflected off a surface at different angles and is scattered.
3.3
What type of reflection is needed to see an image in the object (e.g a mirror or glass)?
Specular reflection.
3.4
Describe the surface that specular reflection occurs on.
Smooth, shiny.
3.5
Describe the surface that diffuse reflection occurs on.
Rough, dull.
3.6
Draw a diagram to show specular reflection.
3.7
Draw a diagram to show diffuse reflection.
4. Colour
4.1
What is frequency?
The number of waves that pass a point each second.
4.2 What is the unit for frequency? Hertz (Hz).
4.3
What is a spectrum?
A series of similar waves arranged in order of wavelength or frequency.
4.4
What is the order of colours in the visible light spectrum from the lowest frequency to the highest?
Red, orange, yellow, green, blue, indigo, violet.
4.5
What is an opaque object?
An object that does not allow light to travel through it.
4.6
Describe why an object will appear red.
4.7
Describe why an object will appear white.
4.8
Describe why an object will appear black.
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