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Grade 8 ScienceColours
How was light discovered?
In the seventeenth century, Sir Isaac Newton placed a prism so that a thin beam of light could pass through it. When the white light passed through the prism, bands of colour emerged from the other side. This is because different colours will refract at different angles producing a rainbow effect.
Dispersion of White Light
From Coloured Light back to White Light
The Colour Spectrum
When white light refracts into different colors, the result is called a spectrum. The colours that form the spectrum are:
- Red- Orange- Yellow- Green- Blue- Indigo- Violet
Place your finger in between the two blocks. What do you see?
Additive Primary Colours
The three additive primary colours are red, green, and blue
How to create other colours
Using the three additive colours in proper amounts, you can create the three secondary colours: Yellow, Cyan and Magenta
Subtractive Primary Colours
The three subtractive primary colours are Yellow, Magenta, and Cyan
How to create other colors
Using the three subtractive colours in proper amounts, you can create the three secondary colours: Red, Green, Blue
What are the differences and similarities
How many cells are in our retina?
Answer
2
The Rods and Cones
Rods - Rods detect the presence of light
Cones - Cones detect colour
Cones
There are three types of cones in our retinas
The first type of cones respond to light of long wavelengths
The second type of cones respond to light of medium wavelengths
The third type of cones respond to light of short wavelengths
Colour Blindness
Although white light contains red, orange, yellow, green, blue, indigo, and violet light, cones in the human eye responds mostly to red, green, blue light.
Cone cells in some people’s eyes are unable to detect certain colours resulting in colour blindness