What is light?

What is Light? What is Light made of? Is it a wave or a particle? If both then how?

WHAT IS LIGHT?

In acient Greek Pythagoras proposed that light is emitted from the eye of a person which enables him to see whereas Epicurus argued that objects emitted light. These theories may seem pointless to many of us today but were a big deal at that time.The ray diagrams of light which quite successfully showed how light bounces of an object were given by Euclid.

In the beginning, we are taught that light is a form of energy which provides us with the sensation of sight but as we grow the definition changes and says that light is an electromagnetic radiation having a certain amount of electromagnetic spectrum. Now, what is radiation? The most simple words in which radiation can be defined is that it is the emission of energy as electromagnetic waves.

WHAT IS LIGHT MADE OF?

Today we say that Photon is the fundamental particle of visible light which travels at a speed of approximately 299,792 kilometres per second but the things were not same at the time of Newton. Newton believed that light is a collection of particles which he called corpuscles. According to him, these particles travelled in a straight line when not acted upon by any external force. No doubt that Newton strongly believed in particle nature of light. Now, the question arises is that what is the particle nature of light?

PARTICLE NATURE OF LIGHT

As already discussed above that light is made of Photons so it will show particle nature. The fact that light seems to travel in a straight line and casts a shadow behind the obstacles is one of the strongest evidence of this. Newton explained the laws of reflection of light on the basis of elastic collision of the particles of light with the surface it is incident upon and the laws of refraction were explained by assuming that the particles of light are strongly attracted by the particles of the denser medium which causes a bending at the surface. 

WAVE NATURE OF LIGHT

Light is made up of particles and these particles have wave like motion because of the continuous collisions with other atomic particles. The wave length is so small that it 'seems' to be a straight line. So, light shows the wave-like nature due to the disturbance caused. Dutch physicist Christian Huygens was the first to suggest that light may be a wave phenomenon but his principal went unnoticed for almost a century. Newton's writings were then challenged by Thomas Young who conducted the double-slit experiment. This experiment established that light coming from two sources interferes and produce maxima and minima.this theory led to the establishment of light as a wave phenomenon. 

So at the end, we can say that light has dual character (both wave and particle) not only light but all the matter around us shows this dual nature. Photo electric effect, reflection are some examples for its particle nature whereas the glaring example of the wave like nature of light is interference i.e they don't hit each other they interfere and then comes diffraction particles don't diffract waves do. Approximately 70% of the phenomena are explained by the wave nature and 30% by the particle nature. 

What is light according to you? wave or a particle? let me know in the comments below.