Illuminate- Part-II

This is specially written for my friend Mohsin,
Colors
What are colors? Let me guess what you are saying…colors are everywhere, its rascal red, bossy blue and gracious green, cute pink and so on. But …now don’t grab your eyeball out when I say but
But are those colors real. I mean can you touch and feel them. One might say what a stupid question have I asked. Look closely what I have asked. I have asked can you feel it. Answer is obviously no. since it’s a quantity which is measured by totally different quantity and organ. We touch and feel things other than light. Isn’t that right?
Light is thing which we need eyes to rely on to feel and know. So what’s the big deal in that? There is enough big deal. Let’s start from the beginning
Light, it is said to be made of different colors, which one can segregate using a prism. Try it you can discover it yourself. It goes like this. Take a prism, and hold a thin bean of white light (note here that no other light will show this property as well as white light will) and make it pass through that prism, voila! On the other side you find the famous VIBGYOR, remember class 6 lesson of light?
V- Violet, I-Indigo, B-Blue, G- Green, Y- Yellow, O-Orange and R-Red.
The purpose of taking you back to class 6 is to find something between these colors. Let’s choose three colors, which by art teacher are primary colors. Red, Blue, Green, colors before blue are violet and indigo, they have something in them common as in blue and red, going to orange, it has some of red.
Now the shocker is for yellow, what about it, its looks different than other, what possibly it can be in common and so here it is, yellow has blue and green in common. Don’t believe me, try it yourself, take a blue led and green led, pass those light through small pin holes on your white washed walls. Your wall will look yellow.
Still confused? Okay the secret here is that since the only primary colors are RGB (not ram gopal burma)
Other colors are just mixture of these. If you are still confused I will advise you to not to look into your water color box anymore, as I’m not talking in terms of paints, but light.
Light makes colors, light has colors, light is made up of RGB, try again yourself by talking 3 LED’s you will prove my point.
Anyway...so...if light is made up of such colors why don’t we see them directly as an individual?
If you read this correctly, I already said it’s a mixture. What we see are mixture of colors.
Now next question should be then why don’t we see everything white since objects reflect lights?
Correctly asked... and I will be happy to answer that.
We have been taught that objects reflect light and hence we them, this statement is half correct. The correct would be objects reflect colors and hence we see them in those colors.
Now why do they reflect few colors? Why not all, because that thing on your desk was made up of plastic and plastic is shiny, right?
Well it has nothing to do with shiny
Let’s switch off they light for some time. Now what do you see…..anything? Something...nothing?
Why nothing? Because light wasn’t there on any object to reflect. So?
So since there was no light to be reflected you couldn’t see it. You did see black. Black color I define is mixture of no colors. And that’s why when there were no colors there was black and I didn’t see any object but just black everything was black, every that shiny plastic thing on your desk.
Bu wait a sec….my keyboard is black now what? I will answer this question later.
As defined and as said things reflect colors, so a blue shirt will look blue because it is reflecting blue and not red and green. Makes sense doesn’t it?
You said we see objects because things reflect colors, so a blue shirt is actually reflecting blue color and rest is being absorbed. Another example would be plain glass, what color is glass? Can’t say?
Well there is no color actually you see as light passes through it directly leaving something or almost nothing to reflect back. So we don’t see any color of glass.
Similarly when we see water, especially in a glass, we don’t see color, as it allows light to pass through, and sea water? Well it reflects the light of sky, no please don’t ask me why is sky blue. But since you have already I will have to tell you it’s because of refraction. And that’s a long story
Right now, lets ‘focus’ on light right now. So we were talking about light and colors. And now that I have proven my point of light is nothing but combination of colors, and colors of objects are mere reflection of those colors which they don’t absorb. Just imagine how you would look like if you could actually see how you look and not by what color you are reflecting…..
Well you do have one thing at your disposal to look how you do look. Remember those old days when we took pics on a roll of Kodak film…that’s the answer. You guessed it right; the negative is your original look.
Pretty scary huh!!
But that’s the truth.
Now bear you beauty with you and be grateful to light which makes you look beautiful which we aren’t :P
To be continued…..

Illuminate - Lights (Part 1)

Purple, yellow, red and green,

The King cannot reach it, or the Queen;

Nor can old Noll, whose power's so great:

Tell me this riddle while I count eight.

Remember this old nursery rhyme? Probably not. And I will save your time when you try to Google its answer for, it’s simply a rainbow. However I don’t want to test your brains, I would rather tell you about colors. But first we begin we will talk about light.

Light can be defined as waves; normally we say light waves, meaning light as waves. But it has another properties of behaving like an electromagnetic wave and particle. Sounds absurd yeah, light as a particle. But it’s true, sorry to hurt your feelings if you thought light is only an electromagnetic waves, or simply to put, waves. Let’s now define waves and particle.

Waves have wavelength and amplitude and some motion they are going through. This property defines colors. Putting colors again on hold for some time. Since light has wavelength and a motion, it’s like radio waves only difference is that you can’t see radio waves but you can see light, not there waves of course.

Don’t argue you can see the radio.

These waves are of order ranging between 380 nanometers to about 740 nm, nanometer is a billionth of meter, which comes down to a millionth of a millimeter. Now you can imagine why you can’t see a wave. Anyway. So light as we found, is like waves. As it has wavelength and a frequency ranging between 405 THz to 790 THz. However we can see from 390-750. Your next question might be what happens to the rest of light? Yes it is there but we can’t see them as our eyes doesn’t have capacity to see all that wavelength. But you probably heard of infra red and ultra violet rays. Those are beyond our vision but they are present all around us, a common example would be microwaves which we use to cook food.

And this is the range where we can see light and different colors. No we are not yet to colors.

After defining and giving enough proof that light is electromagnetic wave. Lets look other side which tells us light is also a particle.

To put in simple, very simple terms, if light was waves and it has infra red and microwave, these infra red and microwaves are said to have radiation effect. I mean, microwaves are type of radiation right? And same goes with infrared. So what I want to say is that, it is an electromagnetic radiation.

I can explain this in simple way by telling you this that light bounces of objects. If light was wave, It should had passed through mirror, or objects, but instead it bounces back, or reflects back. This property is only explained by particles. It means light is also a particle. Light follows the famous duality theory of Newton, which was later verified by Einstein’s quantum theories. According to duality theorem light will act as wave or particle depending upon the condition it is considered for, for example if light passes through a prism, it will act as waves and all those waves will get refracted (deviated) and we get a nice colorful spectrum. But when same light is falling on objects or mirror to be stern, it will reflect showing the properties of a particle.

Particle property can be only understood at quantum level. As it is hard to understand light’s particle property at normal scale what we face at day to day life, nor I would explain this now as we almost deviated from topic.

But if we are to talk about colors, then we will stick to wave property of light. As I gave example that when light is passed through a prism it will refract and will break up into 7 colors namely and in order of, VIBGYOR

Violet, Indigo, Blue, Green, Yellow, Orange and Red.

All these colors are different only because of their wavelengths.

color	wavelength interval	frequency interval
red	~ 700–635 nm	~ 430–480 THz
orange	~ 635–590 nm	~ 480–510 THz
yellow	~ 590–560 nm	~ 510–540 THz
green	~ 560–490 nm	~ 540–610 THz
blue	~ 490–450 nm	~ 610–670 THz
violet	~ 450–400 nm	~ 670–750 THz

So when you see red color you see actually a wave with wavelength ranging between 700-635nm and frequency ranging between 430THz-480THz

When all these colors combine they form white light. The process when light is passed through a prism is the process where one can learn about the numbers of colors and fair idea of frequency of those colors.

The longer the wavelength the straighter the wave will go and that is why red is on top and violet is at bottom.

So where a rainbow does comes from? Is there a big huge giant prim in sky which refracts light and a rainbow is formed. Answer is obviously no. many things refract light, for e.g. water, when you put a straw in glass or spoon in glass it appears broken at the point of immersion. This is due to same fact that light had bend when it entered into water. So this means things are main culprit and which bend light. But what makes them culprit? It’s their density. When light enters from one medium to another due to difference in density light changes its path. Prism was made up of glass and had density higher than air so it bends and when it leaves prism it again bends. While leaving prism due to many different frequency and wavelength modules inside, it splits and all wavelengths become separate, similar thing happens with rainbow, but here water droplets acts as a prism. Since water has different density that air (duh!) so light will again refract when going into water, but colors will deflect further when leaving water droplet. Imagine what a million of water droplet will do; yes they will create a rainbow. Beautiful beautiful rainbow.

So to conclude everything, light consists of colors, many different colors, we see 7 basic, and combining all these we see white light.