Category Science

How are mountains formed?

The first mountains and valleys were the crust formed as a result of the cooling of the molten mass of the earth. As the planet contracted the crust twisted and cracked, forming new mountains.

      Mountains are still being formed by volcanic eruption. A crack is the earth’s crust allows molten rock and ash to be forced out, forming a cone-shaped mountain growing as it continues to erupt.

    Fault-mountains are formed when the earth’s crust cracks, or faults, under pressure from inside, and one side of the break is pushed up against the other to form a cliff.

    The highest mountains are in the Himalayas where some are over 25,000 feet. Only in the Rocky Mountains and in the Andes are there any others over 20,000 feet.

Picture credit: google

Why does an astronaut need a space suit?

A space suit enables an astronaut to survive by providing him artificially with conditions like those he is used to on earth.

    These conditions can be reproduced in a large space craft or space station in orbit, but an astronaut still needs a space suit for operations outside the craft or for an emergency.

     In space men lack the air needed for breathing, the pressure required to stop their blood from boiling and the natural protection of the atmosphere against radiation. All these must be supplied by the space suit which also must withstand the cold of space.

     When an astronaut ventures into space, he leaves behind the safety of the atmospheric blanket which we, on earth, take for granted. His space suit becomes his own personal little world.

 

Picture credit: google

When was the hydrofoil invented?

The hydrofoil, a boat supported clear of the water by underwater wings called hydrofoils, was invented by an Italian, Forlanini, in 1898. In 1918 a hydrofoil, powered by an aircraft engine, gained the world’s water speed record. The commercial hydrofoils now used in Europe are based on the work of German engineers who carried out research into the design of high-power, lightweight engines.

       In the early 1950s hydrofoils were developed in the United States, Canada and Russia using high-powered gas turbines. They are used for both military and commercial purposes.

     Since water is 775 times heavier than air, very small hydrofoil wings will support relatively heavy boats. But, since operating in water puts great loads on boats, the hulls are usually built of high-strength steel.

    The object in raising the hull of the hydrofoil from the water is to avoid the resistance caused by friction and drag. This means the power needed to drive the boat at high speeds is cut by half. Another result is that the hydrofoil travels smoothly in quite rough water, and is not slowed down.

Picture credit: google

Who invented the jet engine?

The first flight by a jet-propelled aircraft was made in Germany on August 27, 1939. Its engine was designed by Hans-Joachim von Ohain, who had conceived the idea while a student at Gottingen University in Lower Saxony. Unknown to von Ohain, the British inventor and aviator Frank Whittle had thought of the idea some years earlier. But his engine did not have its first flight until May 14, 1941.

    Briefly, a jet engine takes in air from the atmosphere, compresses it, and uses it in burning fuel. The mixture of hot gases is then expelled through a nozzle in a powerful backward jet which propels the aircraft forwards.

     This forward thrust is the effect of a scientific principle first explained by the English scientist Sir Isaac Newton (1642-1727). He pointed out that with every action there is a reaction which is equal but opposite to it. Thus when a gun is fired, the forward movement of the shell is matched by the backward recoil of the barrel. In a similar way the reaction to the jet exhaust drives the engine forward. The thrust is obtained by the pressure of the jet against the inside of the nozzle and not, as many people suppose, by the exhaust gases “pushing” against the atmosphere.

     The jet engine, whether turbojet, turboprop, ramjet or turbofan, weights less than a piston engine of comparative power and can be much more streamlined.

Picture credit: google

Where was Morse code first used?

The first message in Morse code was tapped out in the United States over a telegraph line from Baltimore to Washington by Samuel Morse in 1844.

        Morse is often credited with the invention of the telegraph on his return to the United States from a trip to Europe in 1832. During this trip he became acquainted with the works of Michael Faraday on electro-magnetism, which forms the basis of the telegraph. This gave Morse the necessary impetus to go ahead with his work.

    In 1837 Morse exhibited his first truly successful telegraph instrument. By 1838 he had developed the Morse code, an alphabet which consists of dots and dashes representing letters and numbers. In the same year he attempted unsuccessfully to persuade Congress to build a telegraph line.

      It was not until 1843 that Congress voted to pay Morse to build the first telegraph line in the United States from Baltimore to Washington. In the following year Morse sent his famous message- “what hath God wrought?” – On this line.

     Later, Morse was caught in a mass of legal claims among his telegraph partners and rival inventors. He was probably the most successful propagator of the telegraph, although there were many pioneers in the same field long before him.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pictures credit: google

What are Gamma rays?

Gamma rays are streams of electromagnetic waves. They are given off from elements such as radium, when they undergo a process known as radioactive decay.

     In 1899 the British physicist Ernest Rutherford began a study of radioactivity. He found three types of radiation which he called alpha, Beta and gamma rays. Alpha rays were stopped by a thin sheet of paper, beta rays could get through several millimeters of aluminum, and gamma rays could pierce quite thick pieces of lead.

      Alpha rays travel at up to 12,000 miles a second, beta rays from 80,000 to 180,000miles a second, and gamma rays at 186,000 miles a second, the speed of light.

     Gamma rays have proved very helpful in medicine and industry. These rays are also given off by radioactive isotopes obtained as by-products in production processes. They can produce radio graphs of forgings and the seams of boilers and other pressure vessels, where freedom from flaws is vital.

Picture credit: google