Shinning a light through the darkness can certainly make things feel more safe. But what is light. What is it about light that causes it to shine? To understand this simple phenomenon, you need to know how the light works.
Light is made up of waves that travel through space at 1 million meters per second, or 186 thousand miles per second. That is incredibly fast! These waves are made up of tiny particles called photons. A photon is a tiny bit of energy, and it is only considered light when the photon’s frequency (number of waves that pass in one second) matches the spectral pattern humans can see.
Sounds like this may be hard to understand right? It is! Even though we tend to take light for granted, there are many things that we don’t understand about it. For example, even though light travels really fast, it still can not go through objects!
This is because everything in the universe has mass, including photons. Since energy cannot pass through mass without being absorbed, when a photon hits an object it cannot pass through, it stops moving and becomes part of that object itself! Such as when we shine a light through a stone wall, the photons slow down and become part of the wall.
Other times the light will pass through an object. When this happens we say that the object is transparent. The photons are not absorbed by the object, but instead pass through it. All objects have different amounts of transparency. For example, water is mostly transparent, while milk is almost completely translucent.
Sometimes light will also reflect off of an object! Try shining a flashlight at your mirror sometime! When this happens, the photons hit the mirror? They are neither absorbed, nor pass through it. Instead, they are reflected off. Which is why you can see your own reflection.
So, to recap: light is composed of tiny particles called photons that travel at the speed of 186 thousand miles per second through space, objects can absorb or reflect these photons, making them appear opaque or transparent. Objects will also absorb the photons, but reflect them at the same time. This happens when light reflects off of an object and we can see it.
Light is a complicated thing that physicists are just beginning to understand!
Light is truly an amazing part of our universe! It can brighten up a dark room just by traveling through it. Light can also teach us about the special qualities that matter has.
