MOUNTAIN BUILDING

M o U N t A i N     B u i L D i n G

The process involved n mountain building-termed orogenesis  occur as a result of the movement of the Earth's crustal plates. There are three main types of mountains: volcanic mountains, fold mountains and block mountains. most volcanic mountains have been formed along plate boundaries where plates have come together or  moved apart and lava and other debris have been ejected onto the Earth's surface. The lava and debris may have built up to form a dome around the vent of a volcano. Fold mountains are formed where plates push together and cause the rock to buckle upwards. Where oceanic crust meets meets less dense continental crust, the oceanic crust id forced under the continental crust. The continental crust is buckled by the impact. This is how folded mountain ranges, such as the Appalachian mountains in North America, were formed. Fold mountains are also formed where two areas of continental crust meet. The Himalayas, for example, began to form when India collided with Asia, buckling the sediments and parts of the oceanic crust between them. block mountains are formed when a block of land is up lifted between two faults as a result of compression or tension in the Earth's crust. Often, the movement along faults has taken place gradually over millions of years. How ever, two plates may cause an earthquake by suddenly sliding past each other along a fault line.

WHO INVENTED THE SAFETY PIN...............?

S a F E t y     P i N

The  safety pin was the invention of  WALTER HUNT.  HUNT  was a mechanic from New York, whose other inventions include a forerunner of the Winchester repeating rifle, a successful flax spinner, knife sharpener, streetcar bell, hard coal burning stove, artificial stone, road sweeping machinery, velocipedes, ice ploughs and mail making machinery.

In 1834, Walter Hunt built American's first sewing machine, which was also the first eye pointed needle sewing machine. He later lost interest in patenting his sewing machine, because he believed the invention would cause unemployment.

The safety pin was invented while Walter Hunt was twisting a piece of wire, trying to think of something that would help him pay off a fifteen dollar debt. On April 10, 1849, the safety pin was patented. Walter Hunt also thought little of his safety pin as an invention and soon sold the patent for four hundred dollars.

HOT AIR BALLOONS AND ITS PRINCIPLE

 H o T   A i R   B A L L o O n S

Hot air balloons are the oldest and most successful human carrying flight technology. The first balloons worked on the principle that when air is heated, it rises. A hot air balloon consists of a bag called the envelope that is capable of containing heated air. Suspended beneath is a basket which carries passengers and usually, a source of heat (mostly an open flame). Most balloons today use hot air made by burning propane gas. Soon after the first hot air flights, people realized that the gas hydrogen, which is almost fifteen times lighter than air, can be used instead . Filled with hot air or gas that is lighter than the surrounding atmosphere, a balloon travels by moving wind. Since the  wind direction changes with the altitude, the pilot navigates the balloon's direction by controlling the altitude, either by heating the air or by releasing ballasts.