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Sharpen Your General Knowledge

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Shamim Ansary:
How Do Fish See in the Dark?

Since sunlight never reaches the deeper parts of the sea, these regions are always totally dark. Yet fish live here and swim about without bumping into each other.

How is this so? . . . Well, fish actually “see” without their eyes; they use other sensory organs.

The next time you catch a fish, look for a line running along its skin, from the gills to the tail. All fish have this marking, called the lateral line. All along the lateral line are openings in the fish’s skin. These openings allow water vibrations to reach sensory organs which are located under the lateral line.

These sensory organs, in turn, are connected to the fish’s nervous system, and are very sensitive to slight vibrations in the water.

By reading the vibrations in the water around it, a fish can tell when another fish is approaching, what direction it’s coming from, and how far away it is. The fish can also tell when a rock or other object is close by, because these objects cause vibrations as water flows around them.

So a fish can navigate through the darkness without striking another fish or a rock, and can “see” even in total darkness!

Shamim Ansary:
Where Did the Word “Personality” Come From and How Did the Word “Persona” Originate?

In the Greek and Roman theatres, actors wore masks to indicate the different characters they were playing.

The Latin word for mask, persona, came to mean a personality other than that of the actor.

Today, persona, or personality, still refers to the mask a person wears to hide his or her true character while playing a role for the outside world.

Shamim Ansary:
How did the Chinese make the Great Wall of China so long during the Ming Dynasty?

Initially, the Great Wall of China was built by thousands of people working for a total of seventeen straight years.

Many parts of the wall cover mass graves of the workers who died while building it. And it didn’t stop with the Qin dynasty.

For hundreds of more years during the Ming Dynasty, peasants, soldiers, prisoners of war, or criminals were pressed into working on the wall. There are terrible stories of hardships endured by the workers, living with extreme weather and under cruel circumstances.

Most knew that if you were picked to work on the wall, there was a good chance you’d never return home. That’s the basis for one of China’s most well-known, historical poems.

It was written in the first or second century by the poet Ch’en Lin, and it’s titled “Song: I Watered My Horse at the Long Wall Caves.”

Here are some parts of the poem from a translation from The Columbia Book of Chinese Poetry:

I went and spoke to the Long Wall boss:

“We’re soldiers from Taiyuan, will you keep us here forever?”

“Public works go according to schedule, swing your hammer, pitch your voice in with the rest!” A man’d be better off to die in battle
Than eat his heart out building the Long Wall!

I sent a letter to my wife: “Better remarry than wait any longer, serve your new mother-in-law with care and sometimes remember the husband you once had.”

Shamim Ansary:
How Does a Copying Machine Work?

When you put a piece of printed paper into a copying machine, a lens focuses the letters onto a drum or plate coated with a metal that is very sensitive to light.

This metal has an electric charge, but the electric charge disappears from the areas of the drum that the printing isn’t focused on, in other words, it disappears from all the “white” spaces on the page.

Next, the machine spreads a powder over the surface of the drum. This powder is electrically charged too, but it has a charge opposite to the charge of the metal on the drum. Since opposite electric charges attract each other, the powder sticks to all parts of the drum that are still charged, that is, to all the parts covered by the printing.

Finally, a piece of paper is pressed against the drum. Then an electric charge under the paper attracts the powder left on the drum. Since the powder had stuck only to the parts of the drum covered by the printing, the paper now contains a duplicate of the original page. Heat fuses the powder to the paper, and a finished copy rolls out of the machine.

Some copying machines are so fast that they can turn out two copies per second!

Shamim Ansary:
How Long Will the Universe Exist?

Scientists have tried to figure out how long the universe will exist, but they haven’t been able to agree with one another yet.

Some scientists believe the universe will go on forever, even after all the stars are burnt out. The universe will then be completely dark and cold for the rest of time.

But other scientists believe that the universe will someday explode and start all over again. Right now, the universe is getting bigger, and all the stars are getting farther apart from one another.

Perhaps at some time in the distant future, the universe will begin to grow smaller, and all the stars will move toward one another. After many millions of years, all the matter in the universe will be crushed together in a small area, and then it will explode again, beginning the universe all over again!

Scientists have no way of knowing if the universe has already expanded, shrunk, and exploded many times!

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