Sharpen Your General Knowledge

[Shamim Ansary]

What Are Constellations, How Did Constellations Get Their Names, and How Many Constellations Are There?

Constellations are simply groups of stars that people have named for the sake of convenience.

People have been mapping constellations for thousands of years, usually naming them after mythological characters or common items that the group of stars resembles.

For instance, the constellation Leo looks like a seated lion.

If you were to connect the dots, or stars, you would draw a rough outline of a lion.

There are eighty-eight constellations officially recognized by the International Astronomical Union.

The most familiar may be the Big and Little Dippers, or the Great and Little Bear, respectively, and Orion the Hunter.

[Shamim Ansary]

What Is the Difference Between Dissecting Microscopes and Compound Microscopes?

Compared to compound microscopes, dissecting microscopes, also called stereoscopic microscopes-provide a much larger working distance between the lens and stage in order to dissect and manipulate specimens.

The light source on a dissecting microscope is above the specimen since the specimen is often too thick to allow light to be transmitted from a light source below the specimen.

Dissecting microscopes are always binocular, which provides a three dimensional image.

[Shamim Ansary]

Is It Normal for My Child to Speak Rudely to Me When He Is Angry?

“Be quiet, Dad. You never let me do anything!” “I don’t like you.” “You’re not fair! Leave me alone!”

When a child is allowed to spontaneously express his anger, he may say rude, hurtful things, because he’s too young to consider his parents’ feelings. In the heat of the moment, he says what he’s thinking, and he doesn’t understand adult reasoning.

Anger at parents is a normal part of growing up. Learning how to express negative feelings in socially acceptable ways takes time. It also takes patience on the part of parents. Yet many parents react harshly. “Don’t you dare talk to me that way!” “I don’t want to hear that tone of voice.” If parents overreact toward their child for his disrespectful words, he may learn that feeling angry is bad and that angry thoughts shouldn’t be spoken.

While some parents overreact, others feel helpless when faced with outbursts. “Should we allow this behavior?” “Why does he talk this way?” “Am I setting enough limits?” Many parents grew up with strong restrictions on their speech. “Don’t ever say that again. It’s not nice.” They may be reluctant to impose similar restrictions on their child’s expressions of anger, yet they feel uncomfortable listening to him say things they would never have said as children.

Your child needs a chance to speak his angry thoughts, but you also need to put limits on how he expresses himself. If certain words or attitudes are unacceptable to you, tell him. “It’s all right for you to be mad at me, but you’ll have to change your tone of voice.” “When you stop name-calling, I’ll be happy to listen to you.” “I don’t like it when you talk to me that way.” “You’ll have to find another way to tell me about being angry.” Not only do such statements guide him toward better ways of expressing anger, but they demonstrate a respectful way of communicating that you’d eventually like him to adopt.

As you help him control the way he speaks to you, consider his age; a young child lacks communication skills. Also, remember that your child is greatly influenced by your behavior. If you expect him to speak respectfully, offer examples. Don’t say, “Get over here this minute!” “Stop acting like a baby.” “You better listen to me!” Instead, talk to him and treat him as you would like him to treat others.

With patience, limits, and guidance, he’ll gradually learn to express most of his feelings appropriately. However, if you become concerned that he can’t control his anger, consider seeking outside help, such as a parenting class. The way you treat this issue now will set the tone for communication with your child later.

[Shamim Ansary]

Can Cats See In the Dark and Do Cats Have Night Vision In Complete Darkness?

Cats have excellent night vision and can see at only a fraction of the light level required for human vision.

But even with their powerful night vision, cats cannot see in complete darkness.

No animal can see in the dark without at least a little light, however, cats have a distinct advantage on us in the dark.

For one thing, their pupils can expand three times wider than ours can.

Also, they have a layer of crystalline material behind their retinas that reflects light back out, giving their eyes a second chance to pick up images.

This layer, called the tapetum lucidum, is also the reason that cats’ eyes shine eerily at night when they catch a glint of light.

Unfortunately, what cats gain in night vision they lose in daytime sharpness.

While their eyes are perfectly suited to picking up movement, their overall vision is blurry, so much so that if something stops moving, the cat is likely to lose track of it.

Which is why you sometimes see cats watching television, but almost never catch them reading a book.

[Shamim Ansary]

How Should I React When My Child Says “I Hate You Mommy”?

When your young child gets angry with you, she may shout, “I hate you. You’re dumb!” This outburst might come after you’ve said she can’t go outdoors or have a friend over or do something else she wants to do.

A preschooler has a hard time putting her exact feelings into words. She doesn’t know how to say, “Daddy, I think you should let me stay up later tonight because…” or “I’m angry with you because you said…” She’s too young for such articulation and too young to show that kind of respect. Instead she expresses her feelings and anger by saying, “I hate you.”

Some parents accept and understand these words as the beginning of their child’s expression of angry, negative feelings. But all parents can feel betrayed when their child, after receiving love and attention, turns on them over a minor disappointment. It can be frustrating when adult reasoning, logic, and caring fail to keep a child from yelling, “You mean Mom!”

Parents may be tolerant of a three-year-old yelling, “You dumb Mom!” but it’s harder to be understanding when a four-or five-year old says, “I hate you.” A child’s words can feel threatening to parents who don’t like their children to be angry with them. And parents worry that a bad habit could develop.

It is common for parents who hear “I hate you” to say to their child, “That’s not nice! Don’t let me hear those words again.” But a child needs to release her angry feelings somehow, and if she isn’t allowed to express them verbally, she’ll find other, perhaps more destructive ways. She might turn to aggressive behavior such as hitting, or she might take out her anger by becoming deliberately slow, acting excessively silly, or pretending she doesn’t hear her parents. However, if her angry feelings are acknowledged and allowed to be expressed, she’ll eventually learn to state her feelings more appropriately.

If your child says, “I hate you,” offer her other ways to tell you how she feels. Suggest she say, “I’m mad at you,” or “I’m angry,” or “I don’t like what you did.” Acknowledge her feelings, but say, “I want you to tell me in different words.”

And remember, children are natural mimics. Your child uses the word “hate” because she hears it so often. Adults say, “I hate this dress,” “I hate when it rains,” or “I hate it when people do that.” It’s natural for your child to use the word to express her dislike of something or someone, or to point out when you’ve said the word: “Aw, you said hate.” You can take advantage of the fact that she’s a mimic, stop using the word hate, and gradually teach your child to express her anger in acceptable ways.

When your child says, “I hate you,” rather than make an issue of the words, simply restate her words and feelings. Say back to her, “You’re really angry at me, aren’t you? You don’t like it when I say it’s time to come in.” If she hears you express her anger and disappointments in this way, she’ll gradually begin to use similar statements herself.

[Shamim Ansary]

What Is the Most Common Vegetable In the World?

The vegetables that are grown in the largest quantities around the world are the tomato and the potato. But the most widely used vegetable is the onion!

The onion appears in more dishes and in more countries than any other vegetable. In some places, the onion is used to flavor dishes, while in other countries it’s eaten by itself as a vegetable.

The ancient Egyptians ate onions both ways, for the onion was the most common vegetable in Egypt 5,000 years ago. During the Middle Ages, the onion and a relative of the onion, the leek, were the only common vegetables in Europe.

Today, more than 20 billion pounds of onions are produced around the world each year!

Emperor Nero of Rome ate leeks because he thought they would improve his singing voice!

[Shamim Ansary]

What Is the Most Common Vegetable In the World?

The vegetables that are grown in the largest quantities around the world are the tomato and the potato. But the most widely used vegetable is the onion!

The onion appears in more dishes and in more countries than any other vegetable. In some places, the onion is used to flavor dishes, while in other countries it’s eaten by itself as a vegetable.

The ancient Egyptians ate onions both ways, for the onion was the most common vegetable in Egypt 5,000 years ago. During the Middle Ages, the onion and a relative of the onion, the leek, were the only common vegetables in Europe.

Today, more than 20 billion pounds of onions are produced around the world each year!

Emperor Nero of Rome ate leeks because he thought they would improve his singing voice!

[Shamim Ansary]

Why Is the Sky Blue On a Clear Day and How Does Rayleigh Scattering Cause the Red Colors at Sunset?

The sky is blue on a clear day because of a process called Rayleigh scattering.

Light arriving from the sun hits the molecules in the air and is scattered in all directions. The amount of scattering depends dramatically on the frequency, that is, the color of the light.

Blue light, which has a high frequency, is scattered ten times more than red light, which has a lower frequency. So the background scattered light we see in the sky is blue.

This same process also explains the beautiful red colors at sunset.

When the sun is low on the horizon, its light has to pass through a large amount of atmosphere on its way to us. During the trip, blue light is scattered away, but red light, which is less susceptible to scattering, can continue on its direct path to our eyes.

According to classical physics, an accelerated charge emits electromagnetic radiation.

Conversely, electromagnetic radiation may interact with charged particles causing them to oscillate. An oscillating charge is continually being accelerated and hence will re-emit radiation. We say that it becomes a secondary source of radiation.

This effect is known as the scattering of the incident radiation.

The atmosphere is, of course, composed of various gases that together form air. We may treat each air molecule as an electron oscillator. The electron charge distribution of each molecule presents a scattering cross-section to the incident radiation.

This is essentially an area upon which the incident radiation must fall for scattering to occur. The amount of scattered radiation will depend upon the magnitude of this cross-section.

In Rayleigh scattering the cross-section is proportional to the fourth power of the frequency of the incident radiation. Sunlight is composed of various visible frequencies ranging from low frequency (red) to higher frequency (blue) light.

Because it is of a higher frequency than other visible components, the blue part of the sun’s spectrum will be scattered more strongly. It is this scattered light that we see and so the sky appears to be blue.

Incidentally we are also able to explain why sunsets are red. When the sun is close to the horizon its light must travel through more atmosphere.

The blue light will be scattered strongly whereas red light, because it is of lower frequency is less prone to scattering and so is able to travel straight to the observer.

[Shamim Ansary]

How Did Copernicus Change the Ptolemaic System?

The system introduced by Nicolaus Copernicus (1473–1543) was that Earth and all of the planets revolved around the sun in concentric circles. Copernicus was further able to reduce the number of postulated epicycles to 34, still saving the appearances, or not contradicting what was observed. This shifted the fundamental frame of astronomical reference from Earth to the fixed stars. As he wrote:

First and above all lies the sphere of the fixed stars, containing itself and all things, for that reason immovable; in truth the frame of the Universe, to which the motion and position of all other stars are referred. Though some men think it to move in some way, we assign another reason why it appears to do so in our theory of the movement of the Earth.

Of the moving bodies first comes Saturn, who completes his circuit in xxx years. After him, Jupiter, moving in a twelve year revolution. Then Mars, who revolves biennially. Fourth in order an annual cycle takes place, in which we have said is continued the Earth, with the lunar orbit as an epicycle. In the fifth place Venus is carried round in nine months. Then Mercury holds the sixth place, circulating in the space of 80 days.

Copernicus’ conclusions were based mainly on mathematics, drawing on the perennial value of simplicity and the doctrine that nature always behaves in the most “commodious” (simple) way. To the objection that objects would fly off a moving earth, he responded that a moving sky, because it was larger, would move even faster and do more damage.

[Shamim Ansary]

How Much Newspaper Must Be Recycled to Save One Tree?

One 35 to 40 ft (10.6 to 12 m) tree produces a stack of newspapers 4 ft (1.2 m) thick; this much newspaper must be recycled to save a tree.

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What Great City “Disappeared”?

Late in the 16th century, an architect building an underground water main in southern Italy came upon the buried ruins of an old city under 30 to 50 feet of ashes, stones, and mud as hard as concrete.

The city was Pompeii, a flourishing town during the days of the ancient Romans that had “disappeared” and had been forgotten through the Middle Ages. In 1748, workers began to dig out the ruins of the old town, and today Pompeii can be visited by anyone who wants to see what life was like in ancient Italy.

Pompeii “disappeared” after an eruption of the volcano Mt. Vesuvius on August 24, 79 A.D. An estimated 20,000 to 30,000 people perished, as volcanic dust and ash settled on Pompeii and the nearby town of Herculaneum, covering them to a depth of up to 20 feet.

When the city was dug out, many of the homes looked just as they had in 79 A.D., at the moment of the eruption. Some kitchens still contained food that had been buried by the volcano and remained untouched for almost 1,700 years!

Vesuvius erupted during an election campaign in Pompeii, and some houses still have election slogans on their walls!

[Shamim Ansary]

How Many Volcanoes On Earth Erupt Every Year?

About 60 volcanoes in the world erupt somewhere on land every year.

Many others erupt on the ocean floor.

United States is third in the world in volcanic activity, behind Indonesia and Japan.

Volcanoes are usually found near tectonic plates that are diverging or converging.

The Pacific Ring of Fire is a good example an area with volcanoes caused by convergent tectonic plates coming together.

The Ring of Fire has about 452 of the world’s active and dormant volcanoes.

[Shamim Ansary]

How Did the Greeks Figure Out the Size of the Earth?

The Greek Eratosthenes, who lived around 250 B.C., was the first man we know of to figure out the size of the earth. Yet he never traveled around the earth, nor did he have any of today’s measuring equipment. How, then, did he do it?

Eratosthenes used Euclid’s principles of geometry to solve the problem. First he learned that at noon on the longest day of the year, the sun shone straight down to the bottom of a well in the Egyptian city of Syene.

At the same time, in the city of Alexandria, the sun caused an upright post to cast on the ground a shadow shaped like a right triangle, a triangle with one 90° angle. Eratosthenes then measured the other angles and found that one angle was equal to 1/50 of an entire circle.

He then determined that if the lines formed by the post at Syene and the well at Alexandria were extended downward, they would form two sides of another right triangle at the center of the earth. Again using geometry, Eratosthenes proved that one angle of the second triangle was equal to one angle of the first triangle or 1/50 of an entire circle.

Since the earth’s circumference between Syene and Alexandria formed an arc, that arc was also equal to 1/50 of the earth’s circumference. Eratosthenes knew that the distance between Syene and Alexandria was 5,000 stadia (a Greek measure), so he then multiplied it by 50, and found that the distance around the earth was 250,000 stadia, or 24,670 miles.

How close was Eratosthenes back in 250 B.C.? The circumference of the earth is now known to be 24,900 miles! Quite a feat for a time so long ago!

[Shamim Ansary]

How Did Birthdays Come to Be?

Birthdays are one of our very oldest customs. We can suppose that prehistoric mothers and fathers noticed that their children grew up in stages. One day, the baby could only gurgle; then the next, he might repeat a word he heard his parents say.

One day, a baby could only crawl; then the next, he stood up and walked. All of these changes probably seemed mysterious and frightening to prehistoric parents. And they feared anything that was new or different.

To be certain that their children continued growing safely, these parents held ceremonies to scare off evil spirits who could harm their offspring. They offered gifts to the spirits so their children would be protected.

They also gave gifts to their children to encourage them to grow. At these ceremonies, the children played games and held contests to show how strong and skillful they were becoming with each new year.

The custom of testing a child’s strength at his birthday celebration continues today. The big breath needed to blow out the candles on a birthday cake is really a test of strength, a way for modern people to carry on an old custom!

[Shamim Ansary]

What Is the Most Read Newspaper In the World?

Right now, there are more than 7,000 newspapers published around the world, and about a quarter of them are American papers. Each day, Americans buy some 61 million copies of their favorite papers!

The largest-selling paper in the United States is the New York Daily News, which sells about two million copies each day. The Wall Street Journal is second, with about 1.5 million copies sold daily. The Los Angeles Times is third, and the New York Times is fourth.

But of all the newspapers in the world, a Russian paper called Pravda has the largest circulation. About ten million copies of this newspaper are printed each day!

Sixty years ago there were more papers in America than there are today, 2,461 compared to 1,759 today!