Sharpen Your General Knowledge

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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #75 on: May 22, 2011, 05:53:49 PM »
Why Does Black Tea Lighten or Change Color When You Add Lemon Juice and What Causes the Chemical Change?

The simple answer to why black tea changes color is that adding lemon juice alters the acidity of the tea and the color change is an indication of this.

The color change is the same way that litmus paper changes color.

A similar effect can be observed by substituting the tea with some cooked red cabbage juice.

Tea leaves are rich in a group of chemicals known as polyphenols that amazingly account for almost one-third of the weight of the dried leaf.

Both the color of the tea and much of its taste are due to these compounds.

One group of polyphenols, the thearubigins, are the red-brown pigments found in black tea and constitute between 7 percent and 20 percent of the weight of dried black tea.

The color of black tea is also influenced by the concentration of hydrogen ions in the water.

Thearubigins in tea are weakly ionizing acids and the anions, or negatively charged ions, they produce are highly colored. If the water used to brew tea is alkaline, the color of the tea will be deeper due to greater ionization of the thearubigins.

If lemon juice, which is an acid, is added to the tea, the hydrogen ions suppress the ionization of thearubigins, and that makes the tea lighter.

Interestingly, the theaflavins, the yellow-colored poly-phenols in black tea, are not involved in the change in color that is associated with a change in acidity.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #76 on: May 23, 2011, 09:18:00 AM »
Why Are Traffic Lights Red, Yellow, and Green and What Do the Different Colors Mean for Signaling?

Red, green, and yellow traffic lights developed directly from the trial and error of controlling railways during the nineteenth century.

Trains needed advance warning to prevent fatal accidents and collisions.

The first choice was red for stop, which was logical because red had symbolized danger for thousands of years.

During the 1830s, engineers tried using green for caution and clear for go, but sunlight reflecting off clear lights gave false signals.

So engineers solved the problem by introducing yellow for caution and making green stand for go.

The very first traffic light using this system was introduced in Cleveland, Ohio, in 1914.
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Re: Sharpen Your General Knowledge
« Reply #77 on: May 23, 2011, 09:19:39 AM »
What Airline Is the World’s Largest?

The national airline of the Soviet Union, Aeroflot, which is owned by the Russian government, is now the largest airline in the world. Aeroflot has 1,300 planes and 400,000 workers, and carries about 90 million passengers a year to 65 different countries.

The largest airline in the U.S., and the world’s largest airline not owned by a government, is United Airlines, which has 365 planes carrying about 30 million passengers a year.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #78 on: May 23, 2011, 09:22:52 AM »
How Does the Earth’s Rotation Around the Sun Cause the Stars to Rise and Set at Different Times Every Night?

You may notice that when you are stargazing in your yard at 10:00 every night, the stars appear slightly to the west of where they were the night before.

Stars rise 4 minutes earlier every night, and set 4 minutes earlier.

Therefore, over the months, the starry night changes.

Over the period of a year, those minutes add up to 24 hours, so that every 12 months, the same stars show up at the same positions in the sky.

The difference in the stars’ rising and setting times results from Earth’s rotation around the Sun.

The celestial sphere remains relatively still, but Earth moves around the Sun.

The stars appear to be in a different place at the same time each night because, in fact, you are in a different place in space every night.

Because it takes 365 days for Earth to rotate around the Sun, you have 365 slightly different night skies to study.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #79 on: May 23, 2011, 09:23:19 AM »
When Was the Hubble Space Telescope Launched Into Orbit and Who Is the Hubble Telescope Named After?

Two months after the Hubble Space Telescope’s launch in 1990, it was discovered that the primary mirror had not been ground properly, among other problems.

The telescope could not be focused.

While this was a major embarrassment, the dangerous and complex repair mission was a coup.

The space shuttle Endeavor was launched in December 1993.

Its crew captured the Hubble Space Telescope, fixed it, and released it successfully.

The images and data returned since have more than outweighed the early difficulties, promising that the Hubble Space Telescope will be remembered for its scientific achievements rather than its flaws.

Many Hubble observations have led to breakthroughs in astrophysics, such as accurately determining the rate of expansion of the universe.

The Hubble Space Telescope is named after the astronomer Edwin Hubble.
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Re: Sharpen Your General Knowledge
« Reply #80 on: May 24, 2011, 09:47:40 AM »
Where Is the Busiest Airport In the World and What Is the Busiest Cargo Airport Terminal On Earth?

O’Hare International Airport in Chicago, Illinois, was the world’s busiest passenger airport before 2005.

It beat out the previous world’s busiest airport, Hartsfield International Airport in Atlanta, Georgia, in 2001.

O’Hare had 911,861 takeoffs and landings in 2001.

O’Hare International Airport serves as the primary and largest hub for United Airlines and as a hub for American Airlines.

In 2010, Hartsfield–Jackson Atlanta International Airport, located seven miles south of the central business district of Atlanta, regained its ranking as the busiest passenger airport in the world.

The Atlanta Airport has served about 88 million passengers per year since 1999, and has 151 domestic and 28 international gates.

The busiest cargo airport in the world is in Memphis, Tennessee, which happens to be the hub for Federal Express.
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Re: Sharpen Your General Knowledge
« Reply #81 on: May 24, 2011, 09:48:08 AM »
How Is the Earth’s Magnetic Field Important to Life On Earth?

The magnetic field of Earth is very important to life on Earth because it helps deflect harmful cosmic rays and solar wind.

If we were fully exposed to these charged particles the effects on us could be devastating.

Communication systems would be disabled and the particles could cause damage to all living things.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

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Re: Sharpen Your General Knowledge
« Reply #82 on: May 24, 2011, 10:41:24 AM »
Why Do Stars Always Appear to Rise In the East and Set In the West and What Is a Circumpolar Star?

Many of the stars you will see in the night sky follow a path across the sky from horizon to horizon.

Circumpolar stars, however, appear to circle the northern and southern celestial poles without ever rising or setting.

This is because the celestial sphere appears to rotate on the axis between its poles, in fact, it is Earth that is rotating on its axis.

If you draw a circle around the celestial pole in your hemisphere, the North Star in the Northern Hemisphere, at a distance equal to the number of degrees of your latitude, the stars within that circle remain above your celestial horizon all night.

For example, if you are stargazing at 40° latitude, any stars within a 40° radius of the North Star do not rise or set, but are always visible traveling around the celestial pole.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

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Re: Sharpen Your General Knowledge
« Reply #83 on: May 24, 2011, 10:51:21 AM »
What Do the Different Numbers On the Richter Scale Mean and How High Does It Go?

The Richter scale is a logarithmic scale that gauges the magnitude of an earthquake’s force.

Invented by Charles Richter in 1935, it is measured on a seismograph machine, interpreting the data the machine picks up from the Earth’s vibrations.

Each number is 10 times more powerful than the previous number.

For example, a quake that registers 8.0 is 10 times stronger than one that measures 7.0; 100 times more powerful than one that measures 6.0; and 1,000 times more intense than one that measures 5.0.

The scale is from 1 to 9 but is technically open-ended.

Many factors influence what occurs during a quake, but the basic scale is as follows:

1.0 Detectable only by instruments

2.0 Barely detectable, even near epicenter 3.0 Felt indoors

4.0 Felt by most people; slight damage

5.0 Felt by all; damage minor to moderate

6.0 Moderately destructive

7.0 Major damage

8.0 Total and major damage

9.0 Devastating in areas several thousand miles across.

10.0 Never recorded.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #84 on: May 29, 2011, 11:17:24 AM »
How Does the Richter Scale Work and How Many Different Ways Are There to Measure Earthquakes?

The Richter scale measures the magnitude, or size, of an earthquake by using a seismograph to measure the ground motion an earthquake produces.

The scale is logarithmic. A measurement of 7 means an earthquake that has 10 times the ground motion of an earthquake that measures 6.

We can’t feel an earthquake that has a magnitude of less than 2.

Magnitude 5 earthquakes begin to cause real damage. The scale has no top number.

Another way to measure earthquakes is the modified Mercalli scale, which measures the intensity of an earthquake based on observations of the physical damage done.

It uses Roman numerals I through XII, in which I means no damage, VI means slight damage, and XII means total damage, with no structures left standing and objects thrown into the air.

A third way to measure earthquakes is the moment magnitude scale, which uses a seismogram to measure the movement of the Earth’s surface during the quake.
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Re: Sharpen Your General Knowledge
« Reply #85 on: May 29, 2011, 11:17:58 AM »
How Does NASA Brew Beer In Space, What Does Space Beer Taste Like, and How Do You Drink a Coke In Space?

NASA is indeed interested in the questions raised by brewing beer in a microgravity environment.

Scientists who study the physics of gas-liquid mixtures would like to understand, for example, what happens when there is no buoyancy to bring the bubbles to the surface of a fizzy liquid, and the characteristics of fermentation in microgravity.

Two separate space shuttle experiments tackled these questions.

The first investigated how well yeast performs in orbital free fall, not only to see if brewing space-beer might be possible, but also to provide valuable information to pharmaceutical companies with a keen interest in the biology of orbiting microbes.

The space-beer turned out essentially the same as that brewed on Earth.

Its specific gravity and the yeast’s performance when used to brew subsequent batches of beer was comparable to that of control samples on Earth.

However, the total yeast cell count and the percentage of live cells in the space sample were lower. Despite this, the fermentation was significantly more efficient.

This raises the question of whether we can modify the fermentation process, or the yeast itself, to reproduce this effect on Earth.

The second experiment, flown on the shuttle by the Coca-Cola Company, was to test its system for dispensing Coke in a weightless environment.

The challenge was to dispense a fizzy beverage yet keep the gas in solution until the cola is drunk. Because bubbles don’t rise in free-fall, changes in temperature, pressure, or even physical agitation tend to cause the whole thing to degenerate into a foamy mess.

A computer-controlled device adjusted the temperature of the drink during mixing and dispensing, and minimized agitation by dispensing the drink into a collapsible bag inside a pressurized bottle.

The pressure around the bag was slowly released as it filled with drink, keeping the drink under constant pressure and preventing the gas from coming out of solution too quickly.

The end result was a space version of the world-famous fizzy drink.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

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Re: Sharpen Your General Knowledge
« Reply #86 on: May 29, 2011, 11:18:41 AM »
Why Did NASA Put the Hubble Space Telescope In Space and Why Do Space Telescopes Take Sharper Images?

Since telescopes were first used by Galileo in the early seventeenth century, astronomers have dreamed of placing them where Earth’s atmosphere would not get in the way of viewing the universe.

The Hubble Space Telescope (HST) fulfills that dream.

The Hubble Space Telescope, a reflecting telescope, is not the largest telescope made on Earth.

Its amazing clarity comes from its position beyond the distorting interference of Earth’s atmosphere.

Hubble’s earth orbit also allows it to take extremely sharp images with almost no background light.

The HST has a primary mirror that is 7.9 feet (2.4 m) in diameter.

In addition to the telescope unit itself, the Hubble Space Telescope has two cameras, two spectrometers, to break up the components of light, and a photometer, to measure brightness.

Its control system for locating stars uses gyroscopes and special star-tracking and sensor devices.

The Hubble Space Telescope is NASA’s baby, but an international effort went into its construction and outfitting.

In return for the help, other countries get observation time using the HST.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

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Re: Sharpen Your General Knowledge
« Reply #87 on: May 29, 2011, 11:19:26 AM »
Can the Hubble Space Telescope See the End of the Universe?

The space telescope Hubble that was put in orbit in 1990 is able to see seven times farther into space than any other telescope.

The space telescope was carried into orbit by the space shuttle. It is 45 feet long and consists of five separate astronomical instruments.

Astronomers expect to be able to zoom in on many things they do not now understand, such as quasars, pulsars, and black holes. Astronomers are wondering whether or not they will actually be able to see the ends of the universe.

The space telescope will provide us with a clearer picture of the heavens for two basic reasons. First, it will be beyond the dust in our atmosphere, so that its pictures will be much clearer. Second, some of the light from outer space is “screened” out by our atmosphere, which means that some information from distant stars and galaxies is not “getting through” to us.

The Hubble telescope is able to see everything much clearer than telescopes on earth.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

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Re: Sharpen Your General Knowledge
« Reply #88 on: May 29, 2011, 11:20:03 AM »
Why Do Stars Always Appear to Rise In the East and Set In the West and What Is a Circumpolar Star?

Many of the stars you will see in the night sky follow a path across the sky from horizon to horizon.

Circumpolar stars, however, appear to circle the northern and southern celestial poles without ever rising or setting.

This is because the celestial sphere appears to rotate on the axis between its poles, in fact, it is Earth that is rotating on its axis.

If you draw a circle around the celestial pole in your hemisphere, the North Star in the Northern Hemisphere, at a distance equal to the number of degrees of your latitude, the stars within that circle remain above your celestial horizon all night.

For example, if you are stargazing at 40° latitude, any stars within a 40° radius of the North Star do not rise or set, but are always visible traveling around the celestial pole.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"

Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #89 on: May 31, 2011, 02:43:49 PM »
What Was Wrong With the Hubble Space Telescope When It Was First Put Into Orbit?

An error (1/50th the thickness of a human hair) in the curvature of the main mirror caused major focusing problems for the Hubble Space Telescope.

The 2.4 meter (94.5 inch) diameter mirror, was not able to focus all the light it collected to the correct point in the telescope.

NASA suffered great embarrassment for this multi-million dollar mistake.
"Many thanks to Allah who gave us life after having given us death and (our) final return (on the Day of Qiyaamah (Judgement)) is to Him"