Author Topic: Sharpen Your General Knowledge  (Read 21516 times)

Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #225 on: August 13, 2011, 09:27:39 AM »
How Hot Is Lava and How Viscous Is It?

Exit temperatures—the temperature of lava as it comes from the mouth, or crater, of volcanoes—indicate that lava’s heat varies.

The temperature ranges from 700 to 1,200° Celsius (1,300 to 2,200° Fahrenheit). At its hottest, lava is about 10 times the temperature of boiling water.

It also ranges in viscosity, or how thick or runny it is. Lava can be very thin and fluid, or it can be so thick that it almost doesn’t flow.

The estimated daily lava production of Mauna Loa plus Kiluaea, 2 large volcanoes in Hawaii, would fill 65,000 cement trucks.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #226 on: August 13, 2011, 09:29:13 AM »
How Does Ultraviolet Radiation Cause Skin Cancer?

The prevailing theory involves damage to the DNA of skin cells.

It is the shorter UVB rays, which penetrate only the top layers of the skin, that are suspect, while the longer and more deeply penetrating UVA rays cause wrinkles and aging.

In tissue cultures, UV damages the DNA of cells, but humans have an enzyme that repairs it. Due to a genetic defect, some people lack the repair enzyme.

The hypothesis is that in the body such DNA damage occurs all the time and is constantly repaired, but some cells do not get repaired, or get repaired improperly, and this is how skin cancer begins.

Researchers found a specific kind of DNA damage in a gene called CQ that occurs in this way. In the error, two DNA units of the type designated as thymine are side by side, instead of two units of the cytosine type.

The error is called a thymine dimer. It is presumed that the brakes on cell multiplication come off because of it, leading to uncontrolled proliferation of cells into a tumor.

Ultraviolet radiation is implicated in the vast majority of nonmelanoma skin cancers, like basal cell carcinoma and squamous cell carcinoma. It is also linked to melanoma, though less clearly.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #227 on: August 13, 2011, 09:30:21 AM »
What Is Ozone and How Does It Protect the Earth From Ultraviolet Radiation?

Ozone is a unique form of oxygen, and it lies several miles (kilometers) above Earth in the atmosphere.

It serves as a filter against the Sun’s powerful and dangerous ultraviolet rays.

Without this layer of atmospheric protection, ultraviolet radiation would cause many health problems, from skin irritation to cancer in humans, not to mention the harmful effects on other living creatures.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #228 on: August 14, 2011, 02:14:38 PM »
What Are the Different Kinds of Lava and What Are They Called?

The two most prevalent types of lava worldwide, pahoehoe (pronounced pa-hoy-hoy) and aa (pronounced ah-ah), take their names from the native Hawaiian language.

The state of Hawaii is actually a chain of volcanic islands, where pahoehoe and aa are both found in abundance.

Pahoehoe has the shape of thick cords of rope or puffy billows. It can look something like black whipped cream. When highly fluid lava flows, the outer surface area congeals to form a thin, flexible exterior.

The lava inside continues to run, molding the outside layer into ropelike forms. These shapes remain when the entire mass solidifies.

Aa results from oozing semisolid lava. As aa flows, it carries rough, jagged shards of rock along its path. Aa hardens into sharp, splintery, knifelike edges.

You can walk comfortably on cold pahoehoe barefoot, but aa will slice the soles of your shoes.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #229 on: August 14, 2011, 02:15:28 PM »
How Do Rivers and Lakes Exist Underground?

Rivers run underground for the same reasons, and as a result of the same causes, as rivers on the surface.

Earth’s crust soaks up precipitation until it can hold no more. Some areas of the crust are so absorbent that water gathers deep underground.

If the crust’s material is more easily eroded underground, the water will begin to flow under the surface. It may emerge onto the surface at a later point in its course if the terrain changes. In the same way, a surface river can disappear underground if the rock material is more easily eroded there.

Similarly, underground lakes have the same characteristics as surface lakes. Whether water gathers above ground or underground depends on the ability of the surrounding environment to absorb water.

Precipitation falling on saturated ground might erode the softer earth underground until it reaches a resilient layer instead of pooling on the surface.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #230 on: August 14, 2011, 02:16:00 PM »
Why Do We Have Fingerprints and What Beneficial Purpose Have Human Fingerprints Evolved to Serve?

Fingerprints help us in gripping and handling objects in a variety of conditions.

They work on the same principle as the tires of a car.

While smooth surfaces are fine for gripping in a dry environment, they are useless in a wet one.

So we have evolved a system of troughs and ridges, to help channel the water away from the fingertips, leaving a dry surface which allows a better grip.

The unique pattern is merely a useful phenomenon that is used by the police to identify individuals.

Fingerprints are the visible parts of rete ridges, where the epidermis of the skin dips down into the dermis, forming an interlocking structure, similar to interlaced fingers.

These protect against shearing, or sideways stress, which would otherwise separate the two layers of skin and allow fluid to accumulate in the space, and form a blister.

They appear on skin surfaces which are subject to constant shearing stress, such as fingers, palms, toes and heels.

The unique patterns are simply due to the semi-random way in which the ridges and the structures in the dermis grow.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #231 on: August 14, 2011, 03:55:42 PM »
Why Do We Have Fingerprints and What Beneficial Purpose Have Human Fingerprints Evolved to Serve?

Fingerprints help us in gripping and handling objects in a variety of conditions.

They work on the same principle as the tires of a car.

While smooth surfaces are fine for gripping in a dry environment, they are useless in a wet one.

So we have evolved a system of troughs and ridges, to help channel the water away from the fingertips, leaving a dry surface which allows a better grip.

The unique pattern is merely a useful phenomenon that is used by the police to identify individuals.

Fingerprints are the visible parts of rete ridges, where the epidermis of the skin dips down into the dermis, forming an interlocking structure, similar to interlaced fingers.

These protect against shearing, or sideways stress, which would otherwise separate the two layers of skin and allow fluid to accumulate in the space, and form a blister.

They appear on skin surfaces which are subject to constant shearing stress, such as fingers, palms, toes and heels.

The unique patterns are simply due to the semi-random way in which the ridges and the structures in the dermis grow.
"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 #232 on: August 18, 2011, 09:51:49 AM »
Why Do We Have Fingerprints and What Beneficial Purpose Have Human Fingerprints Evolved to Serve?

Fingerprints help us in gripping and handling objects in a variety of conditions.

They work on the same principle as the tires of a car.

While smooth surfaces are fine for gripping in a dry environment, they are useless in a wet one.

So we have evolved a system of troughs and ridges, to help channel the water away from the fingertips, leaving a dry surface which allows a better grip.

The unique pattern is merely a useful phenomenon that is used by the police to identify individuals.

Fingerprints are the visible parts of rete ridges, where the epidermis of the skin dips down into the dermis, forming an interlocking structure, similar to interlaced fingers.

These protect against shearing, or sideways stress, which would otherwise separate the two layers of skin and allow fluid to accumulate in the space, and form a blister.

They appear on skin surfaces which are subject to constant shearing stress, such as fingers, palms, toes and heels.

The unique patterns are simply due to the semi-random way in which the ridges and the structures in the dermis grow.
"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 #233 on: August 18, 2011, 09:53:06 AM »
How Does a Camera Lens Create an Image On the Sensor?

The diagram below shows what would happen if there were three pinholes, each creating an inverted reproduction of the object.

Now, if a converging lens is placed just behind the pinholes it will bend the rays going through it. If the focal length of the lens and the distance between the lens and screen are chosen correctly, then the three reproductions from the pinholes will all be at the same location.

Light rays from the top of the object will converge on the appropriate point on the image. Note that the image is inverted and the same size as the reproductions. What would happen if you had a multitude of pinholes at the location of the lens? The reproductions from all the pinholes would be at the same location, and many more rays from the object would end up at the same place on the image.

The image would be much brighter. So, you can model the formation of an image by a lens as a collection of reproductions of pinholes. The larger the lens, the brighter the image.
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Offline Shamim Ansary

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Re: Sharpen Your General Knowledge
« Reply #234 on: August 18, 2011, 09:54:04 AM »
What Is Soil Made of and How Is It Formed?

Soil is generally made up of many different minerals, elements, and organic matter.

The dirt of different areas has specific components—such as aluminum, iron, quartz, sand, acid, or salt—which is why some plants grow better in some places than in others.
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Re: Sharpen Your General Knowledge
« Reply #235 on: August 18, 2011, 09:55:04 AM »
What Makes You Totally Different From Anyone Else In the World?

If you look down at the tips of your fingers and toes, you will see patterns of circles and swirls on the ridges of your skin. No other person in the world, living or dead, has exactly the same pattern as you, nor will anyone yet to be born. Even though your body grows and changes in many different ways, the exact patterns of circles and swirls of your fingers and toes, your fingerprints and footprints, will remain the same all your life.

You can get a clearer picture of what your prints look like by pressing your finger tips or your feet on an inked pad and then on white paper. Your prints will be reproduced in exact detail. You will see one or more of three main patterns: an arch, or small hill; a loop, or hairpin turn; or a whorl, or circular pattern. You may have all whorls or all arches, or a combination of loops and whorls or arches and loops. Not only are these prints different from anyone else’s in the world, but each of your fingers is different from the next.

Fingerprints and footprints provide foolproof identification of newborn infants by hospitals and of missing persons, amnesia victims, and criminals by police.

The FBI in Washington, D.C., has the largest collection of fingerprints on file in the world, nearly 2,000,000!
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Re: Sharpen Your General Knowledge
« Reply #236 on: August 18, 2011, 09:59:20 AM »
Where Does Sand Come From?

Grains of sand are really very tiny particles of rock. It takes time and certain kinds of weather to turn rock into sand. Rain, frost, and wind can do the job. At beaches, the tide hitting against the rocks forms sand. Salt water, too, forms sand by dissolving minerals in the rocks.

Since rocks are made up of minerals and since sand comes from rocks, you would expect to find lots of minerals in sand. There are, in fact, large quantities of quartz and also some lime, gypsum, feldspar, and even iron ore in sand.
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Re: Sharpen Your General Knowledge
« Reply #237 on: August 24, 2011, 10:55:08 AM »
What Are Minerals and How Are They Formed?

A mineral is a unique composition of elements. For instance, silicon and dioxide interact chemically to form quartz.

The most common mineral, feldspar, which makes up about half of Earth’s crust, is aluminum plus sodium, calcium, or potassium.

Minerals will separate from cooling magma and make their way through veins into surrounding rock, called ore.

Miners search for these veins to find the minerals they contain. Some veins contain single-element minerals such as copper.
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Re: Sharpen Your General Knowledge
« Reply #238 on: August 24, 2011, 10:57:01 AM »
What Plant Has the Biggest Leaves?

Can you imagine a tree as tall as a seven-story building? Sure, some trees in your neighborhood may be that tall. But can you imagine a single leaf that big?

The raffia palm is a tree that grows in the tropics of South America and Indian Ocean islands.

While the average size of most palm leaves ranges from 4 to 20 feet long and 1 to 4 feet wide, a single leaf of the raffia palm can be more than 70 feet long and 19 feet wide!
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Re: Sharpen Your General Knowledge
« Reply #239 on: August 24, 2011, 10:58:32 AM »
Which Plant Has the Biggest Seed In the World and Where Does the Seed Come From?

A tall palm tree called Lodoicea maldivicia, which grows only in the Seychelles in the Indian Ocean, produces the largest single seed in the world known in the plant kingdom.

The two-lobed seed can be twenty inches long.

It grows in huge fruits that look something like two coconuts joined together in an almost heart-shaped arrangement.

To the European sailors who first saw the seeds floating in the ocean, the shape was suggestive of female buttocks.

To the tourists who eventually followed, they looked like wonderful souvenirs, and the trees are threatened in the wild because local residents collect the seeds to sell.

The seeds are also much sought after by amateur palm growers, but they are not easy to cultivate. They have a very slow germination time of several years.

Eventually a shoot grows out of the seed and then goes underground.
"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"