What is Light?

Light plays a very important role in our everyday life. Without light life maybe impossible to observe in our planet. Imagine life without light, our planet Earth will be dark and dead. We are very grateful that we have the sun, as our source of light. Without light we cannot see the beauty of mother Earth. During the day, sunlight provides heat and light which are two types of energy. This is the reason why life exists on Earth. Light helps plants to grow on land and in the sea, providing food for Earth’s animal life. Heat energy keeps the Earth at a suitable temperature for life to exist.

Light is a form of energy visible to the eye. Nothing travels faster than light. As we observe in our weather we can see lightning first before hearing the sound of thunder. Its speed in a vacuum is about 300,000 kilometers per second, but it travels slightly slower through materials such as air, glass or water. Light travels from its sources as a series of electromagnetic waves. Scientist draw arrow-shaped lines called rays to show the direction of travel these light waves. When an object is placed in a beam of light, the object casts a shadow that matches its own shape. This is because light travels in straight lines through space.

The earliest speculations about light were hindered by the lack of knowledge about how the eye works. The Greek philosophers from as early as Pythagoras, believed light issued forth from visible things, but most also through vision as distinct from light, proceeded outward from the eye. Some early ideas of Greeks however, were correct. The philosopher and state man Empedocles believed that light travels with finite speed. The philosopher and scientist Aristotle accurately explained the rainbow as a kind of reflection from raindrops. The mathematician and astronomer Ptolemy was the first person on record to collect experimental data on optics. Through logic and experimentation the Egyptian scientist Ibn Al Haythen he finally discounted Plato’s theory that vision issued forth from the eye. His work influenced all later investigation on light.

We should be very thankful to all the scientist and philosophers that studied out light, because of them we may appreciate light and predict it's cause.