Smiley Thumb Award

Hi,
when I get one of those awards I always wonder who are those people that make these awards! I mean, this must be some special group or what? Maybe I could one day create my own award

hell no.

Anyway I was nominated in the first round of this award because Chape created this brand new award, thanks man for nominating me. So here it is.

The rules:

1. Show your new cool award.

2. Thank whoever nominated you and provide a link to their blog.

3. Tell us what makes you smile.

XKCD makes me smile

4. Select other blogs you want to give the award to. How many is up to you.

I will nominate three which I have never nominated before:

1. Jim Ruebush
2. Aubrey’s Arch
3. A Frank Angle

5. Copy and paste the rules.

Thats done.

Dragallur

 

Advertisement

Why do we use CMYK instead of RGB? (Very colorful post)

Hi,
maybe you too wondered why there is written CMYK on printers. If you have printer or you found out what it means you too know that it is abbreviation for: Cyan, Magenta, Yellow (and K which I will tell later).

What CMY stands for?

 

 

---

Those are the colors that you have to fill inside the machine to print you stuff. Sure this is ok, but why do not we use RGB (red, green, blue)? It seems to be used everywhere so why not in printers?

I thought this because I was thinking that from RGB you can get any color, and sure you can, but only in additive process. Such a process happens for example with light, white light is made up of many different parts with different wavelengths that ADD up. So what does mean that something is red(?), well it reflects only red light absorbing the rest. If you put there blue the material will be even more darker because it will reflect only the combination of blue and red. If you combine everything it would not reflect at all, the object would be black.

This is an example of substractive process with colors. You can see that RGB is darker since you will get it by substracting CMY.

So what you want to do is to start with lighter colors, those are cyan, magenta and yellow. They too are able to add up to all other colors + lighter than RGB in this subtractive form. Even then colors are not perfect in printers so you can not add up to some, bright red, blue  and green wont be displayed very well.

CMYK

RGB

 

 

 

 

 

 

What the “K” stands for? It stands for “Key” which is the color black (it is the KEY thing). While CMY can add up to black, it would not be very pure since the colors can not be clean, it was decided that there will be black added because in most texts black is used. The letter “K” was used because “B” was already used in the RGB model.

Dragallur

PS: check out these two links about colors shared by Jim Ruebush, they are truly amazing:
1) 2)

 

How does optical fiber work?

Hi,
so again, as I was studying some optics I found something that interested me. This time it was optical fiber which is the cable that may be running under your way to work bringing you some interner connection.

---

Optical fibers are cables that are carrying signal. They are made of two pieces of glass with different indexes of refraction. When electromagnetic radiation (light) travels through this tunnel that is made by this cable it bounces off the sides if it is in big enough angle.

There is value called critical angle in which light will always bounce on the edge of two mediums. It depends on refractive index.

This kind of communication is very useful one because glass is very cheap compared to some metals and the communication can not be destroyed by some magnetization. Also

The optical fibre has to be protected in some material, the core itself may be in micrometers.

Optical fibres are usually packed in nice groups.

 

 

 

 

 

those tubes made up of glass are quite flexible.

---

 

By transmitting signal on one side usind some diode you can few kilometers away decode this signal based for example on the number of pauses and number of incoming light waves. Such a communication may reach amazing speeds of tens of gigabytes per second.

There are two main types of optical fibers. First one are multi-mode fibers.Those are the ones for a shorter distance, roughly 600-1,000 meters. There is lot of light running there and it is used to deliver signal in buildings. If you would use it for longer distance the light would stop traveling predictably.

The second type is single-mode fiber. This is much thinner and works on the distance of tens of kilometers. It is used between countries and cities.

Dragallur

 

 

 

Cycling faster than light

Hi,
so while I was learning some optics, I bumped into this page that talked about refractive index which I was just studying. I wondered what is the highest refractive index ever found and there it was, not in number though I think we can calculate it.

---

Refractive index

Since you probably have not read my post about refractive index or you have not heard about it, it is dimensionless value that shows how much is light (electromagnetic radiation) slow in the medium where it travels and also how much it will change its direction when traveling through one medium into the other. You can calculate the index like this:

n=c/v

Where n is the refractive index, c is speed of light in vacuum and v is the velocity in the medium you are talking about. From this, it is easy to see that vacuum and only vacuum has the refractive index exactly 1 because there is nothing that blocks its way and you just divide speed of light in vacuum by speed of light in vacuum.

---

So as the index of refraction increases the only thing that can change is velocity in the medium and it is decreasing.

I found that scientists were able to create stuff in which the light was traveling in “only” 17 meters per second! This is 61.2 kilometers per hour. From steep hill or if you are really good cyclist you can be faster than that, though I think it is bit more easier and safer to do it in car.

So what is the refractive index of this miraclous stuff? Roughly 17,647,059. While normally n lies somewhere between 1 to 3.

What is this thing made of? 

… gas of sodium atoms – a high-tech version of the insides of the bulbs of street lamps – cooled to within a fraction of a degree above absolute zero … the effect of cooling reduces thermal effects, and this in itself contributes to the retardation of light.

There is also special state of matter created that packs those atoms closer together.

Dragallur

 

How to! 4) Go stargazing for the first time

Hi,
since I went out stargazing couple of times already, I would like to mention few things here for you, when you decide to go alone or maybe with your boyfriend/girlfriend stargazing. While I live on northern hemisphere all of these tips will be useful to south people.

---

Preparation

Check out the time when the sun sets where you live. This page is quite useful for that, you just need to insert your location.

It is quite useful to know what these terms mean, astronomical dusk is what you are looking for.

So you need to watch out for the time when first stars/planets appear which will be some time after the dusk, of course there must be clear sky which you need to check on Google forecast [1] or in TV.

Then while it depends on the time of year, it is good to take some extra clothes, because most probably you will be standing still for some time, so you might get cold.

---

How to stargaze

First option: take some sky map on paper with you. You can print some from internet but check if you are printing the right hemisphere. For this, you will need also some light, but not white, since you would never build night vision, take red, eyes are not so sensitive to it.

Second option: take your smartphone and download application with stars, I use Star Walk 2 Free and it is pretty good, especially because there is option for night vision so it is red, this is very useful though you must never lock your phone, because when you want to use it again the light from you display would pretty much destroy the night vision you build up.

What is night vision anyway? It is the activation of all your non color sensors in eyes and the adjusting of your vision in darkness by enlarging the part that collects light, it take about 30 minutes though you may see the effect even after 4 or 5.

---

Pick a good location

Be sure to pick a good location. If you are in big city, than make sure to drive to countryside because the light pollution would just waste your time.

Best is hill though it is good to be on some field or place where there are no trees.

Keep away from any buildings and streets. It is important for you to keep the night vision, one single mistake when you look in street light could destroy the whole process.

---

Enjoy 😉

Dragallur

PS: it is better to go stargazing when there is new moon, otherwise, full moon spoils the view of huge part of sky.

[1] To get in Google forecast just type “weather” and “your location”.

Book review 7) No Country for Old Men

Hi,
today I will continue with the book that I finished last week, it is another McCarthy’s novel.

Book: No Country for Old Men

Author: Cormac McCarthy

Genre: Neo-western, thriller

Pages: 309

Rating: 9/10

---

This has been special experience since it was my first book of such genre. It is novel that meets its purpose, to be: thrilling, bloody and unique.

The story starts when guy named Moss finds $2.4 million when he goes hunting. From this event on, the story speeds up and as the events take turn. There are more and more victims of this “innocent” act because somebody wants the money back and he is willing to do it in the “hard way”.

There are other character paths alongside Moss, those are Anton Chigurh who is the hunter that is trying to get the money and Ed Tom Bell, the sheriff who has to protect Moss but at the same time he is always step back.

I think that you wont regret it and read it in one breath as me. Though I must say that in the end, there were some to me unnecesary parts that were not very important for the main story.

Dragallur

Why are radio telescopes so large?

Hi,
take a Hubble telescope, it has primary mirror 2.4 meters tall. Now take this:

The giant Arecibo radio telescope

I mean the thing above which is Arecibo radio telescope has diameter of 305 meters. Both things are for the same thing, to observe the Universe.

---

So the answer lies in the name. Arecibo is a RADIO telescope which means that it works on quite different wavelengths, actually magnitudes bigger wavelengths since the wavelength of for example visible light for Hubble is 550 nanometers which is quite small while radio waves can have wavelength of hundreds of meters.

This is essentially the key. If you want to see clear image in light (that we can see) you need just a small telescope. Both work the same way though from what I understand you need larger area to collect all of those waves and reflect them on the focus which is above. The equation shows it clear:

θ=1.22*λ/D

Where θ shows how close two points can be to each other without you being able to distinquish them. λ is the wavelength of the light and D is the diameter of your telescope. So you will see best when wavelength is small and diameter is huge since this will lower the angle that you are not able to distinquish. Of course that there is huge difference when you insert meters instead of nanometers so you must compensate it with the diameter of the telescope.[1]

If you want to have a clear image in radio waves, well you have to build Arecibo.. really? Isn’t there another option?

Yes there is! You can build a lot of small radio telescope that would alone be very weak but if you take lot of them you can have a Diameter of kilometers. Such a device is called interferometer which means that is “operates by myltiplying the data from each pair of telescopes together to form interference patterns”.

There is more of them and this one is ALMA observatory.

So those are huge fields or rows of smaller (even 60 meter) discs that collect data. They have to be extremely accurate what is time concerned (atomic clocks).

Dragallur

[1]1.22 is just an empirical value.

Can you see a coin from 400 kilometers?

Hi,
no, probably not with naked eye, I think, though if it would be some special coin, maybe? The point is that you can use some cool things to see such a coin, for example Hubble Space Telescope!

---

Ok, I found some page with physics problems and one of the first was to calculate what is the smallest angle that Hubble Telescope can distinquish. I calculated that it is roughly:

0.0127”

This means 0.0127 arcsecond!!!

How far away football has to be to have the angular diameter of one arcsecond

What about a human eye how good is it? Well eye can distinquish only things that are 1′ away from each other [1], which means one arcminutes, one degree has 60 of those so it is pretty good but not so much as Hubble. But anyway, back to the title, how small is a coin?

I measured the second largest Czech crown to have 2.55 centimeters.

Now how far away do you need to be to not be able to see it with naked eye? We will use this formula to get the diameter:

θ=D/r

Where the diameter (D) is 0.0255 meters. The distance (r) is what we are trying to find and the angle eye can distinquish is θ (in radians). [2]

r=D/θ

If all the calculations went right it should be:

r=87.6625 meters

But beware this is not counting air, humidness and so on so you will most certainly not be able to see coin on this distance.

What about the Hubble telescope? We can use the same equation but for θ we will insert much smaller value!

And yes, you can see the coin from 414,153.744827 meters! Which means that you can see one freaking coin from London 50 kilometers behind Paris! One coin![3]

This is so cool.

Dragallur

[1]You can try this by drawing two dots on paper and then moving away from it, at one point when you are far enough you should be able to see only one.

[2]This equation is simplified but it should work for small angles.

[3]Again, this works only in space because there is nothing that would block your sight.

 

Why is HClO4 stronger than HClO?

Hi,
so this monday we had chemistry class again and because we are learning about halogens our teacher mentioned some acids and she explained why some of them are stronger than other. She got to the point of comparing HClO4, HClO3, HClO2 and HClO. She arranged them in this order in decreasing acidicity explaining why. As I found out over time, she is oversimplifying things, in this post I will try to show why they are in this order.

Almost like water, the picture of perchloric acid. (HClO4)

---

So here we have four acids (to make it faster I will compare only first and last one). Both are same except that there are three more oxygens in HClO4 and the oxidation number of Cl is VII on the left and I on the right. Now this has to be the reason for different properties.

In all of those molecules Cl is the middle one, which means that all oxygens are connected to it with double bond, except one with only simple one which has hydrogen on the other side.

The picture shows the structure of these molecules.

So as you probably know water has what is called “dipole moment”. This is a term that is used for molecules that have partiall charge on one side and the other charge on the other side.

This has very interesting properties but what is important is that HClO4 has this too, and much more than HClO because there are oxygen ions which have charge of -II making chlorine in the middle of them a lot “ripped off” because there are those oxygens with higher electronegativity that are trying to get those electrons to get on the configuration of noble gases.

Now before the conclusion we must clear out the definition of acidic molecule. Such a molecule is acid when it is good at giving H+, so now the question is, why is HClO4 better in giving H+ than HClO?

So the key lies in what happens when these acids break up. When HClO4 becomes ClO4- there is not so much stress into getting the hydrogen back because delocalized electrons from the other oxygens [1] can ease it up making the molecule more stable while in HClO loses only one of two donors of oxygen making the molecule want it back a LOT.

Simply:

Electron withdrawal increases strength.

If you are not sure about this, ask me in the comments or check out the resources that I used.

Dragallur

Resources: 1|2|3|4|5|6

[1] Yes oxygens here have all two free electron pairs which are doing some wonders!

 

 

Book review 6) The Road

Hi,

Last Sunday I finished book: The Road, this was the first book I was able to finish in my dead-line which is one week per book, and wow:

Book: The Road

Author: Cormac McCarthy

Genre: Post-apocalyptic sci-fi

Pages: 287

Rating: 10/10

---

The Road is novel which is about father and boy. It is post-apocalyptic, it is not said what happened but there must be lot of dust in the air because they can not see the Sun and snow is falling grey, also there are trees falling often.

Father and son are trying to get to the south shore of USA. Cities are abandoned, there is not much food and they need to dodge “bad people” how the son calls them.

It is very interesting that in whole book their names are not mentioned, it is narrated mostly through fathers point of view and the son calls him “papa”.

When they are talking to each other it is not usually written who says what and this has very interesting effect, I will quote one of the conversations (There is no main spoiler, it just says what problems they have):

What is it? the man said.

Nothing.

We’ll find something to eat. We always do.

The boy didnt answer. The man watched him.

That’s not it, is it?

It’s okay.

Tell me.

The boy looked away down the road.

I want you to tell me. It’s okay.

He shook his head.

Look at me, the man said.

He turned and looked. He looked like he’d been crying.

Just tell me. We wouldnt ever eat anybody, would we?

No. Of course not.

Even if we were starving?

We’re starving now.

You said we werent.

I said we werent dying. I didnt say we werent starving.

But we wouldnt.

No. We wouldnt.

No matter what.

No. No matter what.

Because we’re the good guys.

Yes.

And we’re carrying the fire.

And we’re carrying the fire. Yes.

Okay.

The book has very interesting effect on you. As you read it and the characters walk on the Road you will find yourself extremely thrilled to what will come, and it is really worth it.

Dragallur