Light Watch

Light is everywhere in our world and we need it to see. It carries information from the world to our eyes and brains. Seeing colors and shapes is second nature to us, yet light is a perplexing phenomenon when we study it more closely.

Our brains and eyes act together to make extraordinary things happen in perception. Movies are sequences of still pictures. Magazine pictures are arrays of dots.

Red, green and blue are the primary colours of light. Mixing them in various ways will make all other colours, including white.

Photo by J.Borno

Visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Other animals can see parts of the spectrum that humans can’t. For example, a large number of insects can see ultraviolet (UV) light.

Photo by J.Borno

The speed of light in a vacuum is defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). Now that, is fast!

Light takes 1.255 seconds to get from the Earth to the Moon.

It takes 8 minutes 17 seconds for light to travel from the Sun’s surface to the Earth.

Sunlight can reach a depth of around 80 metres (262 feet) in the ocean.

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