If we observe nature and everything that surrounds us, things are always happening. Everything is in motion: the clouds, the leaves of the trees, ourselves or the machines we use. For this to be possible, a type of energy must act. There are different types and there is talk of an energy source to explain the cause of each activity. Human beings live because they have enough energy provided by food. The same happens with other sources: heat, air or water.
One of the energies is light. As its name suggests, it comes from sunlight. The Sun emits light rays and the activity of the Earth is maintained by the action of the light energy of the Sun.
Light energy is present at the origin of most of the phenomena that we observe. Day and night exist by the projection of the Sun's rays on the Earth that is rotating on itself. In the cinema we can observe how light is projected. The mirrors we use are smooth, concave or convex and when light hits them we have a certain angle of view. These simple examples show that light energy is part of the world we live in. It is impossible to imagine a day without observing a phenomenon without light energy.
The understanding of light as a phenomenon and the mechanisms of light energy have been changing from ancient times to the present. Today it is known that light energy comes from light waves, and this also exists in sources other than the sun, such as fire or a simple light bulb. The light waves (for example those of a personal computer or a mobile phone) are perceived by our eyes through the cornea and the retina. In this way we can see things. Although not all rays are visible (ultraviolet ones are the best known).
Let's imagine a situation. An individual with glasses is observing the seashore. Your vision will depend on the type of lenses you use. If they are convex lenses, you will not have good near vision. At the same time, the light hitting the water causes a refraction and the individual with the glasses believes that the water is shallower than it actually is. We imagine this scene because there is light energy, also called light. The main energy of this type is that provided by the Sun and its advantages are very resounding: it is cheap, clean and non-polluting energy, it does not run out and it is respectful with the environment.
