The primary colours of light are red, green and blue. Mixing these colours in different proportions can make all the colours of the light we see. This is how TV and computer screens work. If you look at a screen with a magnifying glass you will be able to see that only these three colours are being used.
For example, red and green lights are used to make our brain perceive the image as yellow. When coloured lights are mixed together, it is called additive mixing. Red, green and blue are the primary colours for additive mixing. If all of these colours of light are shone onto a screen at the same time, you will see white. This is different when you are mixing paints.
Each colour of paint is absorbing certain colours and reflecting others. Each time another colour of paint is mixed in, there are more colours absorbed and less are reflected. The primary colours for adding paints or dyes, such as for a computer printer, are yellow, magenta and cyan. If you mix all of these colours together, you will absorb all the light and will only see black, because no light will be reflected back to your eyes. You can easily experiment with this. Hold some coloured cellophane in front of your eyes and have a look around.
Notice how some colours are changed and others look similar. Figure out which colours are being absorbed. It sometimes takes a long time for new scientific knowledge to become widespread.
For example, many people used to think that dogs could only see in black and white. It is now known that dogs have two kinds of colour receptors that allow them to see yellows and purples. Even though the initial experiment was done in , many people are still unaware that dogs can see some colours.
Ever wonder why fluorescent colours look so bright? It is all due to energy, as explained in the article Light — colour and fluorescence.
Experiment with mixing the primary colours of lights and paints using these simulations on the Causes of color website. Find out about how dogs do have some colour vision and how they see the world in this article from Live Science. Read this tutorial about Human perception, Spatial awareness and Illusions on Biology Online to learn about human perception.
Add to collection. Nature of science It sometimes takes a long time for new scientific knowledge to become widespread.
Related content Ever wonder why fluorescent colours look so bright? Useful links Experiment with mixing the primary colours of lights and paints using these simulations on the Causes of color website. Go to full glossary Add 0 items to collection. As a conclusion, things do not have color by themselves — only when light energy hits them, we can see colors. Also, remember our eyes can only see a limited range of colours.
But dogs, cats, mice, rats and rabbits have very poor colour vision. Evolution led bees to adapt ultraviolet vision because flowers leave scatter ultraviolet patterns, allowing the insects to easily identify targets and pollinate. This is what spectrometers are for. Tibi is a science journalist and co-founder of ZME Science. He writes mainly about emerging tech, physics, climate, and space. In his spare time, Tibi likes to make weird music on his computer and groom felines.
Home Other Did you know? What makes things coloured — the physics behind it Have you ever wondered where do colours come from? May 10, Reading Time: 5 mins read. This way, when light hits matter one or more of the following phenomena happens: reflection and scattering. Most objects reflect light, but some are more reflective than others, like metals. This is directly related to the number of free electrons that are able to pass from atom to atom with ease.
Instead of absorbing energy from the light, the free electrons vibrate and the light energy is sent out of the material at the same frequency as the original light coming in. The electrons thus absorb most of the incoming energy, with little or no reflection. If the incoming light energy is much lower or much higher than that required for the electrons comprising an object to vibrate, then the light source will pass through the material unchanged.
This way matter will look transparent to the human eye, such as in the case of glass. If the energy of the incoming light is the same as the vibration frequency of the electrons in the material, light is able to go deep into the material, and causes small vibrations in the electrons.
The vibrations are then passed on from atom to atom, each vibrating at the same frequency as the incoming light source. This makes the light inside the material look bent. Example: a straw in a glass of water. Light and matter. Get more science news like this Tags: colour light. Share Tweet Share. All Rights Reserved.
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