Interesting Fact about Light

Light is a very important part of our lives. Without light we would not be able to see the beautiful world around us, and it wouldn’t even exist. Light is essential for life to thrive on this planet. Animals and humans depend on plants for their food. Plants make their own food, but they cannot do so without light.

A Light from the Sun takes about eight minutes to reach us on the Earth. This is because sunlight travels at an incredible speed of about 300,000 kilometres per second (186,000 miles per second). Nothing in this universe travels faster than that!

A Light travels in a straight line unless an object is placed in its path. If the object is solid the light bends around the edges of the object, creating a shadow. If you place a mirror in its path, the light hits the surface and gets reflected. If you use a transparent object, the light goes through it, but its direction is altered slightly. This phenomenon is called refraction.

A We are able to see an object when light bounces off that object and reaches our eyes. However, solid objects like a wall block the light from passing through to the other side.

Instead, the light hits the wall and bounces back. Therefore, we are able to see the wall but not the objects on the other side.

The colour of an object is determined by the colour of the light it scatters – an object appears green because it scatters green and absorbs the rest of the colours.

A black object is black because it does not scatter any light.

Polnilne baterije

Light usually bounces straight back when it hits a solid object. We can see the object, but it doesn’t reflect anything. However, some objects also absorb a part of the light that falls on them and reflect it. Others reflect all of the light that falls on them.

These objects create reflections. Reflections are seen best on mirrors as they have smooth, flat surfaces that reflect light better. When you stand in front of a mirror, the reflected light from it falls on you and therefore you are able to see an image of yourself on the mirror.

A The Earth’s atmosphere contains tiny molecules of gas and dust particles. Sunlight entering the atmosphere hits these molecules and dust particles. Colours with longer wavelengths, like red and yellow, can pass through the atmosphere without being scattered by these molecules of gas and dust particles. But the colour blue, with its shorter wavelength, is scattered by the gas molecules and the dust in the upper atmosphere. This is why the sky appears blue.

Blue water

Water is actually colourless. However, large amounts of water act like the sky and scatter blue light. This is why seas, lakes and rivers usually appear blue.

Quick & Dirty :

1. What is a light year?
   The distance that light travels in a year is called a light year.
2. What colour is light?
   Light usually appears white, but is made up of various colours of the rainbow: violet, indigo, blue, green, yellow, orange and red (VIBGYOR).
3. Why does the Sun look like a red disc during sunrise and sunset?
   During sunrise and sunset, the sunlight has to travel a much longer distance than during the rest of the day. The scattered blue light is not able to cover this extra distance and therefore does not reach our eyes. The red light reaches us, as the wavelength of red is longer. This helps red light travel further. This is why the Sun appears like a red disc.
4. What do the words ‘opaque’ and ‘transparent’ mean? Solids are said to be opaque, as they do not allow light to pass through them, while water and glass are transparent as light is able to pass through.

will be continuated ....