Introduction to light

Updated: Jun 18, 2020

By Oleksandr Koliakin and Eric


So, what exactly is light? You may say, light is what helps us see. You are not wrong if you say that. However, light is actually so much more. Visible light is only a fraction of the electromagnetic spectrum. Apart from visible light, there are also radio waves, microwaves, and many, many more! The speed of light in a vacuum is 300 000 000 m/s.

What exactly is light?

Light is weird. You may ask, what is light made out of. This is where things get confusing. Light is a form of energy. However, the interesting part about light is that it behaves like a particle and an electromagnetic wave. Scientists call this unique property wave-particle duality. The particle that carries light is known as the photon. We do know however that light is energy and energy can be converted into mass using Einstein's famous equation:

Where E is energy, m is mass and c is the speed of light. Rearranging the equation gives us:

This shows us that we can literally make stuff out of light. This is actually happening all of the time and that is how most likely all of the matter in the universe appeared. Unfortunately, all the matter that you can hope to create by not turning off your lamp when you leave the room and wasting electricity are a few quarks (for more info on them go to the Quantum Mechanics section of the page.)

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