My Science School

A plastic, in the modern sense of the word, is a synthetic or man-made material which can be formed into various shapes. The first plastic material was Celluloid, made in 1868 by an American, John W. Hyatt, by dissolving nitrocellulose under pressure.

      The use of plastic began slowly, but shortages of natural material caused by two world wars forced scientists to develop substitutes. Since the Second World War the making of plastics has become a gigantic industry, which has grown so fast that many people still have only a hazy idea what plastics are. In fact, the term “plastics” is as general as the word “metals”. The high-temperature cone of a rocket and the highly inflammable table-tennis ball are both plastics, just as lead and steel are both metals.

    However, all plastics have some things in common: first, they are entirely man-made and not found in nature; secondly, they consist of large molecules of an organic nature; thirdly, at some stage in their manufacture they are liquid and can be shaped; and fourthly, in their final state they are solid.

    Most of the raw materials for plastics are produced by the petroleum and coal industries. Scientists are able to produce different properties in plastics so that they can be used in a tremendous variety of articles.

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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.

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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.

 

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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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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