How does light work?

What is light? Light can be described as a form of energy and the ability to do things. There are lots of forms of energy, like heat, sound, motion, chemical reactions and electricity.

Light is a form of electromagnetic energy that travels in waves at almost 300,000 km per second or 186,000 miles per second!

Light can pass through some materials, like glass or water, these are called transparent materials. Light can be stopped by other materials, and these are called opaque materials. When some light passes through matter and some is absorbed, this phenomenon is called translucent

Light travels primarily in straight lines and strikes objects, it bounces off these objects which allows us to see images. So whatever the source of light is, the energy travels forth in straight lines in all directions striking objects, bouncing off in other directions until the light runs out of energy, and the light fades.

Reflection and refraction

When light interacts with different objects and materials some really cool things can happen. When light “bounces” off something it’s called Reflection, and there’s different levels of reflection based on how much light is absorbed by the material, or if light is scattered the the surface of the material.

Most objects scatter light when they reflect the energy, this is called diffuse reflect, a mirror on the other hand has 100 percent reflection in the same angle as the light source, this is spectacular reflection. There are few naturally occurring materials that produce spectacular reflections,, still water on a bright day is one of them.

The invention of the mirror dates back to over 6000 years ago from evidence of polished stone tools. Modern mirrors use both polished metals and glass to create almost 100% perfect reflection of light. Since we’re looking at an image of ourselves, we see light reflecting off a surface so when we raise our right hand our image raises their left. This means we see the opposite side of our bodies moving and working.

Perception of light

We see images all around us based on how light is reflected off the surfaces of the materials and objects around us. When light enters our eyes it meets a host of cells in the back of the eye called the retina. Cells of the retina are composed of two types, rods that allow us to see shape and movement while cone cells allow us to see color.

The shape of our eye affects how we see as well, if our eyes are more oval in shape we might have near sightedness or far sightedness.

Glasses help shape light by bending the beams, this is called refraction. If we’re nearsighted we can see things that are close to us, so we need light waves to spread out more then we can see things that are far away.

If we’re farsighted, we see things that are far away more easily, so our glasses need to bring light waves closer together and we can then see things that are close to us.