Chemistry{♥}

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This blog was opened by (SOPHIAARON) to accomodate (SOPHIA)'s Science journal.
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archives

Videos. (:

-------------Physics------------
Liquifaction.
How to get out of a quicksand.
Math Definitions : What Is Terminal Velocity.
Newton's 3 laws of motion.
Titration Technique using a burette
How to use a pipette.
Indroduction to Frictional force.
Tacoma Bridge Collapsed!
---------------Chemistry----------
Forensic Video
Periodic table song(:

Crystal structures: graphite and diamond
Chromotography- Separation of MIxtures
Separation: Iron from Salt & Sand Mixture
Steam Distillation
Fractional Distillation
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Design: doughnutcrazy
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Physic- 27

A question that Mr Lim has asked us on Thursday:

I posted it in a picture format. Click to enlarge.

I'm not sure if it's clear...

Physic- 25

Question: What is Centre of Mass???????

Answer: The center of mass of a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated. The center of mass is a function only of the positions and masses of the particles that comprise the system. In the case of a rigid body, the position of its center of mass is fixed in relation to the object (but not necessarily in contact with it). In the case of a loose distribution of masses in free space, such as, say, shot from a shotgun, the position of the center of mass is a point in space among them that may not correspond to the position of any individual mass. In the context of an entirely uniform gravitational field, the center of mass is often called the center of gravity — the point where gravity can be said to act.
The center of mass of a body does not always coincide with its intuitive geometric center, and one can exploit this freedom. Engineers try to design a sports car's center of gravity as low as possible to make the car handle better. When high jumpers perform a "Fosbury Flop", they bend their body in such a way that it is possible for the jumper to clear the bar while his or her center of mass does not.[1]
The so-called center of gravity frame (a less-preferred term for the center of momentum frame) is an inertial frame defined as the inertial frame in which the center of mass of a system is at rest.

http://en.wikipedia.org/wiki/Center_of_mass

Physic- 24

I came across this Law while browsing through youtube videos just a while ago and I've decided to blog a little about it.

The law that I've came across is called 'Hooke's Law'. I believe many of us are not familiar with this law because it's totally a new word I've never known that this word actually existed.
So let us explore(:

In mechanics, and physics, Hooke's law of elasticity is an approximation that states that the extension of a spring is in direct proportion with the load added to it as long as this load does not exceed the elastic limit. Materials for which Hooke's law is a useful approximation are known as linear-elastic or "Hookean" materials.
Hooke's law is named after the 17th century British physicist Robert Hooke. He first stated this law in 1676 as a Latin anagram[1], whose solution he published in 1678 as Ut tensio, sic vis, meaning:

"As the extension, so the force."

Reference: http://en.wikipedia.org/wiki/Hooke

An informative video that I've triggered me to upload this post(:

Physic- 23

During Science class today, we did an experiment on the oscillation of the pendulum bob.

What I've learnt today through this experiment:

The dependent variable will always be the time for one full swing, or the period.The three tested independent variables will be the mass, the angle, and the length of string.The controlled variables will be the attachment point of the string, the string itself, the method used to time the pendulum, and the variales we are not currently testing. These will remain the same for each test, so that we know they won't affect the results.

First, we used the 'normal' pendulum bob. After we did 3 tries, we got the average of the 3 readings. The reason behind this is to ensure the accuracy of the experiment.

When we were done with it, we coated the normal pendulum bob with a piece of plasticine. This is the increase the mass of the bob.

To find the period of the pendulum, we would take the average time taken for 10 oscillations and divide by 10. That would give you the period. Please correct me if I'm wrong.

Look around you, we might find something that has oscillation. Saw it? Yeah, it's the grandfather clock. The one with one pendulum bob and swings from right to left? It's an example of an oscillation too! (:

Physic- 22

Refering to Lishan's question on the discussion forum of the IVLE:

What's a burette?

In case if you do not know how a burette looks like, please refer to the top(: there's a picture(:

--> A burette is a vertical cylindral piece of laboratory glassware with a volumetric graduation on its full lenth and precision top, or stopcock, on the bottom. Burettes are extemely accurate: class A Burettes are accurate to 0.05cm cube. The precision of a burette makes careful measurement with a burette very important to avoid systematic error.

History of A burette:

Francois Antoine Henri Descroiziles developed the first burette(which looked more like a graduated cylinder) in 1791.

Joseph Louis Gay-Lussac made an improved version of the burette that Francois made. The improved version consisted of a side arm. Joseph also coined the terms 'pipette' and 'burette' in an 1824 paper on the standarisation of indigo solutions.

A major breakthrough was done by Kari Friendrich Mohr. He redesigned the improved burette by placing a clamp and a tip at the bottom.

References: wikipedia

Physic- 21

Frictional force can be both useful and nuisance:

Friction between the ground and our feet or shoes helps us to walk/run. Without friction, we might just be probably walking and slipping or just walking on the same spot over and over again.

Nuisance frictional forces such as wear and tear. Or wearing down machines in factories. Friction also produces heat. However, it's wrong to say that heat produced by friction is bad. This is because by rubbing our hands together and producing heat, may warm us up during cold weathers.
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Write down 3 ways on how friction can be reduced:

1) Using lubricant: By using this, the object that is contacting with the other surface would be in a sense 'smoother'. Like windows.

2) Ball Bearings: when we transport heavy loads by putting ball bearings below to make it easier to move.

3)Use of wheels and rollers: Roller blades can be in an instance. It reduces friction because there's lesser contact between the ground and the wheels.

Sophia(:

Physic- 20

What is the densest object on Earth?

I've researched on it and i've gotten various answers:

1) Neutrons.
Explanation: Many subatomic particles are considered points, and thus could be thought of as having an infinite density, the neutron has a measurable size (about 10-15 m in diameter) as well as mass (about 1.7 x 10-27 kg). Those numbers result in a density of about 1018 kg/m3.
That value matches the estimated density of neutron stars, the densest objects known in the Universe. (A black hole's mass is concentrated in an immeasurable singularity). A single neutron is a smaller (MUCH smaller!) version of a neutron star, and the Earth is loaded with neutrons.

2) The densest element on Earth is osmium.
Osmium (pronounced /ˈɒzmiəm/) is a chemical element that has the symbol Os and atomic number 76. Osmium is a hard, brittle, blue-gray or blue-black transition metal in the platinum family, and is the densest natural element. The density of osmium is 22610 kg⁄m³ (22.61 g⁄cm³), slightly greater than the density of iridium, the second densest element. Osmium is used in alloys with platinum, iridium and other platinum group metals. Osmium is found in nature as an alloy in platinum ore. Alloys of osmium are employed in fountain pen tips, electrical contacts and in other applications where extreme durability and hardness are needed.

reference: http://www.physlink.com/Education/askexperts/ae299.cfm
http://en.wikipedia.org/wiki/Osmium

Physic- 19

<-- Example of a 24k gold.

What does 24K gold and 18K gold mean?

Pure gold is 24K. Which means, 18K gold is 18 parts of pure gold and 6 parts of alloy. According to the internet, pure gold is not expensive. It's just that pure 24K gold is soft. Because of that, we might not be able to wear it or something, it might just drop.
So when we include alloys, the 'gold' would be 'harder'.
Alloying gold also produces its varying colors including white, red, green, and blue. The formulas each refinery uses are closely guarded secrets but some common combinations follow. For example, gold when alloyed with silver is white or with copper, reddish.

Done.

Physic- 18

Ms Gomes was talking about The Big Bang theory in class, which I don't see the reason why but I've decided to post something about the big bang(:

Ok, I know that this concerns nothing about Physics. I just want to express my views.
Although I AM a Christian, but I think I'm certainly a weird one.
I do believe in God, but all these theories about big bang and how the universe is created out there. It's really bizarre if we were to think hard about it. Where is universe? Where is the boundary? To us, the world outside the Earth maybe a universe, but perhaps, the 'universe' we are currently refering to is not the 'real' one? Maybe there's billion or trillions more universe out there. Where is the boundary of the universe? *I'm not against anything* just plainly my views.
It makes us really bemuse of how Earth is formed and everything around us. If the big bang theory really is true, then how are they going to prove how we 'came' to Earth? How animals are formed? Chemicals reaction? This is so weird.
Seriously, there are so many things for us to ponder about on Earth. For science or for others, there are many things that do not have fixed answers. I shall end this here(:

Physic- 17

What is Joules?

One joule is the amount of energy required to perform the following actions:
The work done by a force of one newton traveling through a distance of one meter;
The work required to move an electric charge of one coulomb through an electrical potential difference of one volt; or one coulomb volt, with the symbol C·V;
The work done to produce power of one watt continuously for one second; or one watt second (compare kilowatt hour), with the symbol W·s. Thus a kilowatt hour is 3,600,000 joules or 3.6 megajoules;
The kinetic energy of a 2 kg mass moving at a velocity of 1 m/s. The energy is linear in the mass but quadratic in the velocity, being given by E = ½mv²;

taken from: http://en.wikipedia.org/wiki/Joule

Physic- 16

Quite an interesting question asked by Mr Lim yesterday:

How do astraunauts pee/poop?

This are the steps to poop like an astranauts. *(laughs)*

Step #1: Get a baggie and some duct tape.
Step #2: Put the mouth of the baggie up against your anus.
Step #3: Tape the baggie in place with some duct tape. Make sure you get a REALLY
good seal!
Step #4: Poop. DO NOT PEE!! Peeing is covered in NASA Technology Transfer
Bulletin #A101-753A.
Step #5: When you are done pooping, CAREFULLY remove the baggie from your butt.
Step #6: Wipe. Wiping is covered in NASA Technology Transfer Bulletin #A101-
753C.
Step #7: CAREFULLY dispose of wiping material in baggie.
Step #8: Seal the baggie using the duct tape that held it to your butt.
Step #9: Dispose of the baggie in the nearest trash receptacle.

Not only that, you have to contend with Newton’s Third Law, which is: “For every action, there is an equal and opposite reaction”.
Simply put, this means if you let loose a big one without some kind of restraining mechanism, you’ll go flying right across the space
module, probably upsetting some important experiment involving how bugs reproduce in space.

You know what? I've read on wiki answers that astranauts drink their pee. GROSS! ): Well maybe it's not true. We still can bring water along into space right? One question, will the water float around if you just pour it into the space? If that's the case, I guess it must be really cool(:
Weightlessness is quite amazing after all.

Another set of answers:

Astronauts brush their teeth just like they do on Earth. There is no shower on the Shuttle, so astronauts must make do with sponge baths until they return home. Each Space Shuttle has a toilet that can be used by both men and women. Designed to be as much as possible like those on Earth, the units use flowing air instead of water to move waste through the system.
Solid wastes are compressed and stored onboard, and then removed after landing. Wastewater is vented to space, although future systems may recycle it. The air is filtered to remove odor and bacteria and then returned to the cabin.

That's it for this post(:

Physic- 15

What is terminal velocity?

A free falling object achieves its terminal velocity when the downward force of gravity (Fg) equals the upward force of drag (Fd). This causes the net force on the object to be zero, resulting in an acceleration of zero. Mathematically an object asymptotically approaches and can never reach its terminal velocity. As the object accelerates (usually downwards due to gravity), the drag force acting on the object increases. At a particular speed, the drag force produced will equal the object's weight (mg). Eventually, it plummets at a constant speed called terminal velocity (also called settling velocity). Terminal velocity varies directly with the ratio of drag to weight. More drag means a lower terminal velocity, while increased weight means a higher terminal velocity. An object moving downward with greater than terminal velocity (for example because it was affected by a downward force or it fell from a thinner part of the atmosphere or it changed shape) will slow until it reaches terminal velocity.

A video about terminal velocity:
http://www.youtube.com/watch?v=1ukf2vntU44

The velocity at which the driving forces are cancelled out by the resistive forces. Terminal velocity depends a great deal upon the shape of the object that is facing the direction it is moving. Once an object has reached terminal velocity, the object is not accelerating (a=0), therefore it is not speeding up or slowing down. It is a constant velocity unless the driving forces or the resistive forces change. Typically, Terminal Velocity is only a possibility when you are dealing with fluid friction as opposed to contact friction like static or kinetic friction.

Resistive Forces
The forces that try to resist motion. The force of fluid friction (from a liquid or gas) plays the main role in creating terminal velocity.

In the movie above, it is important that you notice the following things: (use the arrow buttons on the right side of the movie to go just one frame at a time)
Initially the only force acting on the books is the force of gravity (their weight). Only as the books start falling does the force of air friction (drag) begin acting on the books.
The faster the books go, the greater the force of air friction.
Even though the two books are identical in mass and shape, the one with more surface area facing the direction of motion reaches its terminal velocity first.
The terminal velocity of each book can be seen on the graph when the velocity vs. time graph shows no increase (remains flat). It can also be seen by watching the digital velocity display. When the velocity no longer increases, the book has reached terminal velocity.

source taken from: http://www.regentsprep.org/Regents/physics/phys01/terminal/default.htm

Physic- 14

This was a question asked by Mr Lim on Monday:

*If an object is moving in one direction of a force 1N, would a force of 1N be able to push the object to an opposite direction?

Answer: No, the force of 1N would not be able to push the object to an opposite direction. This is so as the two forces are both equal, but in opposite directions, cancel each other out. I guess it has quite the same theory as Mr Lim sitting on the see-saw with lisa on the other end. By canceling each other out means that both the two object would come to a rest. A greater force would be needed to overcome the object's speed.

********** EVERYONE! please correct me if I'm wrong(: Thank you********************

Tag reply.

Tag reply to Mr Lim's LONG tag:

Hello(:

Firstly, I did post about Newton's 3 laws as I've promised(: I DID!!(: It's under the heading- Physic-9 understand. Yep, it's under there, i'm sure(: I've also posted on the priciples of moment. That's really weird, I posted way before you came to my blog. I posted in the afternoon at around 4.30 pm, and you came my blog at 11.34pm. I think there's something wrong? I hope you'll see this post when you visit.
About the Principle of Moment, it's under the heading- Physic- 13. I think that's about it. Thanks for your compliment, I'll do a better job next time(:
By the way, what about the 'videos' you were talking about? I don't quite understand you>.<>

Sophia.

Physic - 9- understand

Laws of Newton:

1) A stationary object will stay stationary unless you exert a force on it. Similarly, an object in motion will continue moving unless a force acts on it. ie Friction.

2) It is talking about force, measured in newtons, being determined by multiplying mass with acceleration.

3) I think my previous explanation is alright(:

Physic- 13

Principle of Moments:

What I have infered from today's lesson:

These are somewhat related to moments:

1) Lever

2) Beam Balance

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The Principle of Moments, is also known as Varignon Theorem. states that the moment of any force is equal to the algebraic sum of the moments of the components of that force. Moment has the same meaning as torque. Accroding to wikipedia, torque, is an important basic concept in physics. Other than that, torque is often used in civil engineering and mechanical engineering. Mr Lim mentioned that once you have mastered the basics of that, you can actually design and building. Wow...but designing a building for people now is quite off the topic now. heh.

Torque is usually used to describe a rotational force down a shaft, for example a turning screw-driver, whereas "moment" is more often used to describe a bending force on a beam. The turning effect is called the moment of a force(: and it makes work easier for us.

above is a picture of 2 persons balancing on a see-saw.

This is the formulae:

Moment of a force, M = F x D

Moment of a force, M = Force x Perpendicular distance from the fulcrum to the line of action of the force.

So therefore, the S.I. unit of moment of a force is Newton Metre ( Nm ).

Does the beam balance always turn anti clockwise or clockwise?

--No, this is dependable. We would see different direction the beam balance move when we stand at different views.

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Question: If a lever(see-saw) has nothing on the sides, what's the moment acting on the fulcrum?

Answer: The moment is 0. This is so as the concept of moment is F x D, there's no force acting on the lever at all. Well, other than gravity. So, force = 0 and distance from force is also = to 0, then 0 x 0 = 0(:

References: Science matters.

http://en.wikipedia.org/wiki/Moment_(physics

By the way, does anyone knows what's denison?

Physic- 12

What is Liquifaction?

Liquifaction is a made up word, but the process is totally real. If you find some sand that is saturated with water (think shores of the ocean, or on a river bank in a low lying area) you can jump on it. Go up and down a bunch of times and continue jumping while keeping your feet over the same spot each time. Pretty soon, you'll feel the ground start to get soft, and jiggle, and then, you'll sink into it!It's the closest thing to quicksand that you'll find this side of the Sahara and it's tons of fun...that is, until you can't get out and the tide starts coming in.

I think quicksands are related to liquifaction too. Do you think so?

Soil liquefaction describes the behavior of soils that, when loaded, suddenly go from a solid state to a liquefied state, or having the consistency of a heavy liquid. Liquefaction is more likely to occur in loose to moderate saturated granular soils with poor drainage, such as silty sands or sands and gravels capped or containing seams of impermeable sediments [1]. During loading, usually cyclic undrained loading, e.g. earthquake loading, loose sands tend to decrease in volume, which produces an increase in their porewater pressures and consequently a decrease in shear strength, i.e. reduction in effective stress.

source from: http://en.wikipedia.org/wiki/Soil_liquefaction

I posted a video under my video link, please take a look at it(:
It's about liquifaction.

Physic - 11

Find out what is quick sand and what is the best way to get out of it.

Basically, a quicksand is a colloid hydro gel consisting of fine granular matter (such as sand or silt), clay, and salt water. Water circulation underground can focus in an area with just the right mixture of fine sands and other materials such as clay. The water moves up and then down slowly in a convection-like manner throughout a column of sand under optimal conditions, and the sand remains a generally solid mass. This lubricates the sand particles and renders them unable to support any significant weight, since they move around with very little friction, behaving more like a liquid when exposed to stress. Since the water does not usually go all the way up through the sand, the sand above does not appear to move at all, and can support leaves and other small debris, making quicksand difficult to distinguish from the surrounding environment. Quicksand is basically just ordinary sand that has been so saturated with water that the friction between sand particles is reduced. The resulting sand is a mushy mixture of sand and water that can no longer support any weight.

If you step into quicksand, it won't suck you down. However, your movements will cause you to dig yourself deeper into it. In this article, you will learn just how quicksand forms, where it's found and how you can escape its clutches if you find yourself hip-deep in it.
Quicksand is typically not very dangerous, but it’s one of the last things you’d want to run into if you were sand boarding. Check out the sand boarding article, video and images at Discovery’s Fearless Planet to learn more.

"With quicksand, the more you struggle in it the faster you will sink. If you just relax, your body will float in it because your body is less dense than the quicksand."

When you try pulling your leg out of quicksand, you are working against a vacuum left behind by the movement, according to The Worst-Case Scenario Survival Handbook. The authors of the book advise you to move as slowly as possible in order to reduce viscosity. Also, try spreading your arms and legs far apart and leaning over to increase your surface area, which should allow you to float.

Here's a video that I've found on YouTube. This video actually summarised everything above:

Here's the link: http://www.youtube.com/watch?v=JHCW_bqWLTo

Reference links:
http://en.wikipedia.org/wiki/Quicksand
http://science.howstuffworks.com/quicksand.htm

Physic - 10

2 questions were given by Mr Lim on Thursday, sorry for the late post. I'll post the answer to each question on separate posts.

Here's the first one:

1) What's concave and convex meniscus?

Answer:

Diagram A is the concave and diagram B is convex meniscus.

A convex meniscus occurs when the molecules have a stronger attraction to each other than to the container.

Conversely, a concave meniscus occurs when the molecules of the liquid attract those of the container.

yeah, this is about it.

referances: http://en.wikipedia.org/wiki/Meniscus

Physic - 9

Sir Isacc Newton's 3 laws of motion:

First law
There exists a set of inertial reference frames relative to which all particles with no net force acting on them will move without change in their velocity. This law is often simplified as "A body persists its state of rest or of uniform motion unless acted upon by an external unbalanced force." Newton's first law is often referred to as the law of inertia.

Second law
Observed from an inertial reference frame, the net force on a particle of constant mass is proportional to the time rate of change of its linear momentum: F = d(mv)/dt. This law is often stated as, "Force equals mass times acceleration (F = ma)": the net force on an object is equal to the mass of the object multiplied by its acceleration.

Third law
Whenever a particle A exerts a force on another particle B, B simultaneously exerts a force on A with the same magnitude in the opposite direction. The strong form of the law further postulates that these two forces act along the same line. This law is often simplified into the sentence, "To every action there is an equal and opposite reaction."

Taken from: http://en.wikipedia.org/wiki/Newton's_laws_of_motion

Looking at the first law of Newton, I don't really get what he really meant. I think that the first law is trying to get to us that unless a force is acted to a stationery object, it would not move. I don't really know. I think I will blog about it when i understand its meaning behind it.

Second law is as confusing. I think it is trying to say that the speed of the object swing is dependant on the mass of the object, is that right? I doubt so): similarly, i will blog as soon as possible when i got the answer.

Third law: It's trying to tell us that the force will be passed on the the next object when the force is tranferred to it by the initial object. The last sentence of the law has explained everything we need to know(: hooray! I'll get better explanation next time, hopefully tomorrow or the day after tomorrow.

I promise(: I will post the explanations? (:

Physic - 8

First of all, I'm going to talk about what we did and I learnt on Thursday's science lesson(:

On Thursdy, Mr Lim let us watch Home Alone. It was the first time of me watching it.
Well, this is not the main point of today's post.
In that movie, forces were used almost everywhere. There were tension used. Friction was against the rolling wheels. I believe everyone of us take forces for granted in our everyday lives, right? I'm not the exception too.
Let's think about it this way, without forces, are we able to do work? The answer is no. Like for example. If there happens to be no gravitational force on eath at all, what would happen? We would be floating around the earth like nobody's business. Worst of all, we know that we living things need food and water. Without gravity, we won't be able to consume our food too! See how important forces are! However, there are harmful forces too. Such examples are: Earthquakes and volcano eruptions. These are terrible natural disasters.

Weight is a force. Weight is a gravitational pull from the centre of the earth. Mr Lim pointed out some misconceptions within us too:
The apple did not drop on Sir Isacc Newton's head. He SAW the apple dropping down the tree.
Thanks Mr Lim(:

Sir Isacc Newton, is the father of mechanic, statics and some other great dicoveries. He came from a very poor family. Isacc always self-studied, he was a genius. His father was poor and not educated. Therefore, when Isacc was born, his father did not know what to name his son. He then decided to name his son after his own name, Isacc Newton.

According to Mr Lim, he said that debates were going on about whether Isacc was a gay or not. Was he really a gay? Does that really matter? What really matters is what the great scientist had contributed to the world, isn't it? Facts are facts, we can't change facts even if we continued debating. More over, that happened decades ago, what could be possible be done?

I will blog about the 3 laws of motion later(:

Physic- 7

This is what we have learnt today(:
It’s about how Mr Lim managed to find out the density on the Moon.

W=Weight mg=mass
W=mg--> gravitational acc
Mass:[kg] -->beam balance

Weight[N]-->Spring balance
On earth, our density --> 10m/m³
on moon--> 1.6 N/kg
Wm=40(1.6)
=64N
We=40(10)
=400(N)

So basically, Newton is '10 times' more than W.

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Things about time:

1 Milli seconds = 0.01 seconds

Athletes heartbeat are always at a very constant low rate. Why?
That's because they will need a lot of energy to compete, and if the heart beat too fast at the before the competition, their enerygy would be used up very quickly.
*When heart beat really fast, it would pump out more blood around the body.*

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Question: Why do you need to take average?
Ans: That's the ensure the accuracy of the experiment.

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What is the significant/importance of speed?

Importance of speed:

Without speed, we might be all for late for everything! Imagine us being late for exams, work, school and everything? That would be definitely horrible. Speed helps us to get things done.

I would like to talk about speed of light(:

The speed of light in the vacuum of free space is an important physical constant usually denoted by the symbol c0 or simply c. The metre is defined such that the speed of light in free space is exactly 299,792,458 metres per second (m/s). The speed of light is 186,000 miles per second or 299,792,458 meters per second or the time it takes for the light to turn green before the guy behind you starts honking. When people refer to light, they are referring to light in a vacuum, though many vacuums are so full of dirt and dust and cat hair that not much light can travel through it. The speed of light is of fundamental importance in physics. It is the speed of not just visible light, but of all electromagnetic radiation, and it is believed to be the speed of anything having zero rest mass,[3] and of gravitational waves. Einstein's theory of relativity together with the principle of causality requires that no matter or information can travel faster than the speed of light.[4][5] Speeds faster than that of light are encountered in physics but, in all such cases, no matter or information is transmitted faster than c.

referance taken from: http://en.wikipedia.org/wiki/Speed_of_light and http://www.why-is-the-sky-blue.tv/speed-of-light.htm .

Looking at the second website, I just felt like asking why is the sky blue? LOL, I have never thought it before in my life. I just took it for granted. Maybe it's how the earth is formed and create. Everything is so incredible(: Why is the sea blue? Reaearch has shown that there's no definate answers to the second question yet.

As you ponder the clear, blue sky, you may wonder just what produces such a beautiful color. The sky is not haphazardly blue; its color is no accident of nature. There is a real scientific phenomenon behind the color of the sky. The sky is blue because of a process called Rayleigh scattering. This process involves the scattering of light off of molecules in the atmosphere. Though the sky is blue from your position on the ground, it actually looks black from space or on the moon. Since there is no atmosphere in space, the light from the sun is not scattered and colored light doesn’t reach your eyes. Without our atmosphere, we would look up to see black sky. Even a slightly thinner atmosphere would change our sky, making it appear lighter blue.

referance taken from: http://www.wisegeek.com/why-is-the-sky-blue.htm

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We have also learnt about GMT today(:

GMT simply represents: Greenwich Meridian Time. It sounds so complicating.

Times zones are configured based on using an agreed upon starting point. This has been referred to as Greenwich Mean Time, universal time, and Greenwich Meridian time. Since GMT is point zero for calculating times, all time zones are understood as being a certain number of hours ahead or behind this universal time. Taking this as the basic standard, time zones are established into fifteen degree slices all around the world. The use of fifteen degrees as an acceptable standard was first developed in the late 19th century, and remains the basis for the twenty-four time zones that currently operate around the world. An interesting fact is that while the starting point for fixing the arrangement of time zones remains the same, the actual facility that once resided at the median time location is no longer there. During the 1950s, the famed Greenwich observatory, the starting place for the concept of developing time zones, was moved to Sussex, in England. However, the original site is still considered to be the prime meridian that sets the foundation for all time zones.