How did museums start?

Museum

Museum as we know them today grew out of the private collections started by wealthy people during the middle ages.

Where could you go to see an Egyptian mummy or the paintings of great artists?  Where could you see the bones of dinosaur?  The answer is “a museum.”

Just you may collect stamps or coins, museums are places that collect and display valuable art works, stuffed animals and many other interesting historical and scientific objects.

The first museums were founded in ancient Egypt.  They were usually places where art, music and the sciences were studied.  Museums as we know them did not develop until many centuries later.

They grew out of the private collections of works of art and other treasures started by wealthy people during the Middle Ages.  Today there are many different kinds of museums to visit.  Art museums, for example, collect and show paintings, statues and other masterpieces of art.

And you can see model dinosaurs in museums of natural history.-Dick Rogers

How does a siren work?

Siren

A siren is a kind of whistle which makes a loud noise as air is blown through holes in a spinning cylinder or disk.  It is a wailing noise

When a fire truck roars through the streets, its loud siren warms people to get out of the way.  An ordinary air siren has two cylinders, one inside the other.  The cylinder contain a number of holes.

When the fireman presses the button, an electric motor spins the inner cylinder and air is pushed through the holes.

When the holes in the inner cylinder are lined up with the holes in the outer cylinder, puffs of air escape and cause vibrations.  When the vibrating air (sound waves) reach our ears,  you hear the familiar ooooooOOOOOOEEEEEEeeeeee noise of the siren.

The faster the inner cylinder spins, the greater number of puffs of air, and the louder the siren.  A newer kind of siren makes its wailing sound electronically.  It does not have a moving parts like the older types. – Dick Rogers

What is parchment?

Parchment

Parchment is the dried skin of goats, sheep or other animals, treated so that it can be written on.

If you had lived long ago, in medieval days, you might have read books whose pages were made of animal skins instead of paper.

The first books made of pages bound together in a cover were made of parchment.  This is a king of material made from the skin of goats, sheep, and other animals.

Because parchment is expensive to make, the parchment on which a book was written was often considered more valuable than its content.  Frequently the ink was erased so that the parchment could be reused.

By the 1500s, paper had replaced parchment for all but the most formal documents.  The important-looking paper on which the diploma you get when you graduate from school is usually printed is called “parchment paper.”

Parchment paper is a kind of paper that is treated to look almost like real parchment, it lasts fro many years, but it is not as expensive as parchment.-Dick Rogers

How is nylon made?

Nylon

Nylon is a product of a chemical process in which carbon, nitrogen, oxygen and hydrogen are united to form a strong, tough material.

Nylon is a strong, long-lasting synthetic material.  Its uses range from such things as shear hosiery and fishing lines to toothbrush bristles and molded parts for machinery.

Nylon is made from common elements obtained from coal (carbon) and air (oxygen and nitrogen) and water (hydrogen).  These elements are heated, mixed and treated to such a way that they are changed into a substance called “nylon salt.”  

The nylon salt becomes a thick, gooey liquid when it is heated.  The melted nylon is spread out into a thin sheet to cool.  When hard, the sheet is cut into chips.  The chips are then melted and manufactured into final products.

To make yarn for weaving stockings and fabrics for clothes, the melted nylon is pushed through time notes in a metal plate.  Several threads of nylon are then twisted together into a single yarn and then stretched to make the nylon strong.–Dick Rogers

What is a doctorate degree?

Doctorate Degree

A doctorate degree is the highest degree awarded to a person by a college or university.

In the United States, a student who graduates after four years of study in a college or university normally receives a “bachelor’s degree” and usually specializes in a field of study called his major subject.

Some students begin work in their new professions after earning a bachelor’s degree.

Many do not stop their studies at this point, but go on for graduate studies that lead to a highest master’s degree, and then to a doctor’s degree to practice in special professions such as medicine, dentistry, law, or the field of education.

Degrees are awarded (conferred) at a ceremony called “commencement” – a term that means the beginning of a career outside academic surroundings.  A person on whom a college or university has conferred the doctorate is properly addressed as Doctor (abbreviated “Dr.”).–Dick Rogers

What is the difference between a lake and a pond?

Lake

Generally, a pond is described as a small body of still water without an outlet.  Lakes are usually much larger and deeper and often are fed by rivers and streams.  Generally, lakes differ from ponds in size.

A lake is commonly descried as a large body of water with land all around it.

A pond is usually smaller than a lake.  It is a quiet pool of water so shallow that rooted plants often grow completely across it and the bottom is usually covered with mud.

The cool water in a lake is often too deep for plants to grow except around the shore.  What people know as a pond or a lake, however, may differ from one place to another.

Pond

In some places, for example, a pond may be called a marsh.  And some large bodies of water commonly known as seas are really lakes, such as the Caspian Sea and the Dead Sea.

The “bowl” that holds a lake or pond is called the basin.  The basins of ponds and lakes may get their water from rain or be filled with water that flows into them from rivers, streams, or sometimes even from underground springs.–Dick Rogers

What makes a railroad crossing signal go on?

Train crossing signals are worked automatically by electricity made to flow when the train’s wheels touch certain sets of rails near the crossing.  People walking or riding need to be warned at an approaching train when they are about to cross the tacks on the highway.

Railroad Crossing Signal

Safety gates may close.  Electrically operated waving arms and flashing red sights accompanied by the ringing of a crossing bell can also warn of an approaching train.

When you see a train speeding down the track, you may wonder how the signals know it is coming.

The safety signals are operated automatically by an electric current that flows through special sets of rails near the crossing.  When the train’s  metal wheels touch the rails, they close the electric circuit. Causing the safety gate to close, the red lights to flash and the crossing bell to ring.

When the train is safety through the railroad crossing the wheels touch a second set of electrified rails on the other side, which turn the signals off and open the safety gate for the traffic.–Dick Rogers