About Light

• 1 Light travels at a speed of about 300,000 km per second – nothing in the universe can travel as fast as light!
• 2 The sunlight you see outside right now actually left the sun about 10 minutes ago – travelling 149 million kilometres to get to the earth.
• 3 Light is a form of energy that is made up of electric and magnetic fields, called electromagnetic radiation. 
• 4 Of all the forms of radiation and light on the electromagnetic spectrum, humans can only visibly see a very small amount of light.
• 5 The visible light we see as humans is not the same as how many other living things see the world. In fact, dogs can only see things in black, white and grey, and some insects see colours that none of us can see.
• 6 Space is dark because light is only visible when it has an object of which to bounce off.
• 7 Lasers are a special form of light that does not occur in nature and can only be created by human technology.  Laser light is different to natural light in that it contains only one colour (making it monochromatic),  and all the waves in laser light travel in one direction parallel to each other (which is why you get the strong ‘beam’ of light lasers are well known to have). Lasers are important to modern technology, and are used in many ways – including medical technology, bar code readers in stores, and DVD players use lasers too!
• 8 A rainbow occurs occurs when drops of rainwater meet sunlight. The multi-color arch is produced by a fundamental process called refraction, or the “bending” of light.
• 9 Sunsets are also a result of refraction. In astronomy, sunset is the point when the trailing edge of the Sun’s sphere disappears below the horizon. The brilliant array of colors that appear in the sky during a sunset are created by scattered airborne particles passing through rays of white sunlight traveling through the atmosphere. Because the evening air contains more particles than morning air, sunsets are typically more radiantly coloured than sunrises.
• 10 Photosynthesis is an important process where plants use energy from sunlight to convert carbon dioxide into food – making light a key source of life!