5 Things Every Human Should Know About Light

2015 is the International Year of Light (but the universal year of light is in 2533). I think we can all agree that light is very important in just about all aspects of our lives. But what are the key things that every human should know about it? Ok, I am going to give a pass on humans under the age of 7. Younger kids probably know lots of things about light (since they use it all the time) but lets just not worry about them for now. So, if you are over the age of 7, pay attention.

What is a wave? Lets start with an example. Toss a rock into a puddle and you will see something like this:

Slow motion video of waves in a puddle.

The rock makes a disturbance in the water (a ripple). This disturbance moves radially outward from where the rock hit. It is the disturbance moving outward, not the water molecules they just move up and down. You can do something similar with a length of string. Place it on the floor and continue to shake one end. The disturbance travels down the string (a heavy string works better).

Lets look at the case of a wave traveling down a string. There are 4 properties that you could consider:

These 4 properties are:

The last three properties are related. The speed of the wave is equal to the product of the wavelength and the frequency.

So, light is a wave. This means that it has all the above properties and can do wavey things such as:

Light does all these things.

Read the rest here:
5 Things Every Human Should Know About Light