How does a lie detector work?

A lie detector is a kind of machine that records changes in such things as a person’s breathing and heart and heartbeat while he is being questioned.  Sometimes it is hard to know when a person tells a lie.  But most people feel guilty when they lie.

When a person lies, certain body reactions may take place which he cannot control or may not even be aware of.  The may be a change in blood pressure or breathing, a faster heartbeat, or other emotional signs.

A lie detector is a kind of machine that detects and records these changes in the body. 

A person who takes a lie-detector test sits in a chair with an arm cuff to measure blood pressure and pulse.  A respiration tube around the chest records the rate of breathing.  Still other devices may be attached to detect other body changes.

The body’s reactions to questions are recorded on a moving chart.  If the chart shows changes in breathing, heartbeat, or other signs while the person is being questioned, chances are he is not telling the truth.  He usually will not show these signs when he answers questions truthfully. – Johnny Wonder

 

Where is paper money made?

PAPER MONEY IS PRINTED BY THE BUREAU OF ENGRAVING AND PRINTING AT WASHINGTON, D.C.

The Bureau of Engraving and Printing in Washington, D.C., is where the United States government prints paper money.

Skilled engravers use sharp tools to cut the designs for bills into steel plates.  Many engravers work on each plate.  One works on the portrait, another adds the letters, and still others complete the rest of the design.  Workers use the engravings to make plates for printing presses.

A high-speed press prints paper money in sheets of 32 bills.  First the backs are printed, then the fronts, or faces.  Finally, the serial numbers, letters, and seals are added.

The notes are printed on special paper with tiny red and blue threads scattered in it.  No one but the federal government can use it.

The sheets of new money are inspected for imperfect bills, then cut into separate bills and packaged.  Another inspector then counts the bills and makes sure every packages has 100 bills in it. – Johnny Wonder

How is vinegar made?

Vinegar is made by exposing fermented fruit juice to the air to form a sour acid that gives the liquid its “vinegar” taste.

Vinegar is a sour liquid that is popular as a seasoner for salads and other foods.  It is also used to preserve, or “pickle,” meals and vegetables.

Vinegar gets its name from the French word for  “sour wine.”

Vinegar is made from the juice of any fruits or berries.  It can also be made from honey and malt.  In the United States, older vinegar made from apple juice is most often used.

To make older vinegar, the vinegar maker first change the fruit sugar in fresh apple juice into a weak alcohol through a process called “fermentation.”

Then pours it into a large vat loosely filled with beech wood shavings that have been soaked with strong vinegar.  As the liquid dribbles down through the vinegar-soaked shavings and mixes with the air, the alcohol in the older changes to the sour acetic acid that gives vinegar its sharp, sour, “vinegar” taste.

 

What is the longest river in the world?

Longest River

The Nile River in Africa is probably the longest river in the world.

The longest river in the world is probably the Nile River found in Africa.  It flows 4,187 miles from central Africa to the Mediterranean Sea.

If the Nile were placed in the United States.  It would reach almost from the West Coast to the East Coast.

This great river has often been called “Egypt’s River of Life.”  For thousands, of years its water as made life possible for the people of the dry desert lands through which it flows.

The ancient Egyptians considered the Nile to bring creed.  They build great temples and tombs along the river banks.

Photo courtesy:  salon

What are the earth’s magnetic poles?

Earth's Magnetic Pole

The earth is like a huge magnet with its own North and South magnetic poles, which are located several hundred miles from the true North and South Poles.

Many people think that a magnetic compass needle points, to the North Pole.

Well, a compass obviously does point in a northerly direction, but not to the true North Pole.

The earth has two other poles, called “magnetic poles.”

Scientists believe that the earth is like a huge magnet with its own magnetic North and South poles.

But the magnetic poles and the true North and South poles are not located in the same places.

The North Magnetic Pole is in northern Canada, several hundred miles away from the North Pole.

The South Magnetic Pole is on the opposite side of the earth in the Antarctic.

Because of the wide separation between the geographical and the magnetic poles, compasses usually point a little to one side of the true poles.

Since the locations of the magnetic poles are known, sailors may make allowances, and sail their ships in a true direction.

 Photo courtesy:  digitalradiance

What is the Rock of Gibraltar?

Gibraltar

The rock of Gibraltar is a big “rock” fortress that guards the gateway to the Mediterranean.

The Rock of Gibraltar is a high, rocky point of land on the southern coast of Spain.

“The Rock,” as it is commonly called, is only about 8 miles long and less than a mile wide.  It guards the narrow passage between the Atlantic Ocean and the Mediterranean Sea, and, for this reason, is often called the “key” to the Mediterranean.

Long ago, Britain made the Rock into a great fortress.  It is so well protected that “as safe as the Rock of Gibraltar” is a common saying.

Tailless monkeys call Barbary apes live on Gibraltar.  A legend tells that the British will never lose Gibraltar as long as the monkeys remain there.

In ancient times the Rock of Gibraltar was called one of the two Pillars of Hercules.

The second “pillar” stood across the Strait of Gibraltar on the African shore.

The pillars marked the limits of the familiar world, through which sailors dared not sail into the unknown.

 Photo courtesy:  wayfaring

What are crystals?

Crystal

Crystals are rocks and minerals in which the atoms or molecules were arranged in very regular patterns as the crystals were formed.

Perhaps you think of a crystal as a beautiful gem.  You are partly right.  Diamonds and rubies are crystals.

But no all crystals are gems.  Each grain of salt and sugar that you sprinkle onto your food is also a crystal!  And every snowflake that falls in winter time is made of tiny crystals of ice.

Crystals are rocks and minerals in which the storms or molecules were arranged in very regular patterns as the crystals were formed. These shapes usually consist of smooth, flat surfaces that have sharp edges and corners.

Each kind of crystal has its own special shape.

Salt crystals, for example, have cube like shapes.  Because a snowflake is a crystal of frozen water, it always has six sides.

Many rock crystals are so beautiful that we use them as gems.  Usually, however, we do not use them in their own shapes but cut them to make them the shape we want.

 Photo courtesy:  nasa

What is a venus-flytrap?

Fly Trap

Venus-flytraps are small insect-eating plants.  When an insect touches the trigger hairs in the plant’s leaf, it snaps shut like a trap.

You have probably seen so many plants spoiled by insects, but have you ever seen a plant that “eats” insects?

One of the strange insect-eating plants is the Venus’s-flytrap.  This small plant is found largely in the shady bogs and low pineland of North and South Carolina.

Its leaves are folded in the middle.  On the surface of each leaf are three sensitive hairs.

When an insect touches one of these trigger hairs, the halves close suddenly, like a trap snapping shut.

Spines around the edges form a cage that holds the victim fast.

Digestive juices inside the leaf digest the insect and the trap then opens to  wait for another meat.

Insects are not the only found of the Venus-flytrap.  Like other green plants, their leaves manufacture starch, which the plants use as food.

These curious plants catch insects in order to obtain a curtain chemicals they need which is lacking in the soil where they grow.

 Photo courtesy:  wallwork

How are the great lakes formed?

Lakes of North America

The basins of the great lakes of North America were probably scooped out thousands of years ago by ice age glaciers.

Nowhere else in the world is there a group of fresh water lakes so large as the Great Lakes of North America.

The Great Lakes were probably scooped out many thousands of years ago by ice age  glaciers.  During that time, much of North America was covered with a vast sheet of ice.

As the glaciers slowly pushed south, they gouged out the basins for these lakes, acting much like giant bulldozers.  Then the earth warmed and the ice melted back to the northern boundaries.

The water from the melting ice filled the Great Lakes for the first time.  Today, rain and snow and many streams bring water to them.

All the lakes except Lake Michigan are bordered by both the United States and Canada.

Lake Superior is the largest.  After Lake Superior come Huron, Michigan, Erie, and Ontario.

Special ships, called “lakers,” carry cargoes of oil, grain and iron ore across the lakes.

Photo courtesy:  geographicguide

 

What is a tidal wave?

 

Destructive Waves

A tidal wave is a large ocean wave, usually caused by an earthquake or violent storm at sea. 

Sometimes great, destructive waves sweep in from the sea like a huge tide.  Most people call these “tidal wave,” but they have nothing to do with true waves.

Scientist have a special name for tidal waves.  They call them “tsunami” (pronounced su NA me), a Japanese word that means “storm waves.”

A tidal waves, or tsunami, is not like ordinary ocean waves along the seashore.

A tidal wave, or tsunami, is not like ordinary ocean waves along the seashore.

A tidal wave can start when an earthquake or volcanic eruption or violent storm takes place far out in the ocean.

The waters above the spot are violently stirred and great wave is set in motion.  When a tidal wave very low tide.  Then the great wave comes crashing in as a solid wall of water.  Some are so big that they can destroy whole villages.  Often, the waves are so small they cause no damage at all.

Photo courtesy:  newprophecy