David Amos

  For millions of years, the Sun has given people a source of energy which is clean, cheap and absolutely natural. Without energy from the Sun there would be no life on Earth. But how do we control energy from the Sun (solar energy) to provide, For example, a constant energy for our homes? One solution is solar panels. These are large sheets of black-coloured glass which concentrate the heat and are positioned in such a way as to catch the rays of the Sun for as long as possible. Directly underneath the solar panel is a water tank, in which water is heated up by solar energy, giving a supply of hot water to the home . Today, there are also installations which can transform solar energy into electrical energy. This is done by using solar energy to boil water. The boiling water turns a turbine connected to an electricity generator . Another system uses photoelectric cells . Each cell is made of two layers of silicon, one on top of the other. The upper layer contains phosphorous,...

  In 1939, World War Two began in Europe. This war would last for almost five years. In Germany, Hans von Ohain designed and installed a completely new type of engine in an aircraft, an engine which would enable the aircraft to fly at a truly high speed. This was the first jet engine, pushed forward by air which was first sucked up and compressed, and the exhaust gases expelled at great pressure. Two years later, quite independently of von Ohain, an English engineer, Frank Whittle achieved the same results. But the first people to install the new motor in an aircraft were the Germans. Their Messerschmitt Me 262 , used during the last stages of the Second World War, gave the best performance.                 By the end of the War, jet engines had begun to be used in passenger aircraft, too. Now, people could fly at higher speeds and so complete their journeys within an unbelievably short time. Passengers tr...

  The passion for the motor car turned into racing and by the end of 19 th century the first racing car competitions had begun. To begin with, there were no limits or rules as to the types of cars taking part in different races, and the competition was open to almost any method of transport on four wheels. Then from 1906, the competition was divided into two major groups of ‘formula cars’, both of which were free to experiment with technical improvements to make the car perform better. The first group were the course formula cars , with specifications as to the number of engine cylinders, fuel consumption and the size of the car. The second group were the free group which had no specification limits.                 Formula 1 racing began in 1946, and from the time it was officially establish in 1950, it was destined to become the most famous racing car competition in the world. Formula 1 began as a raci...

       The first bicycle was just two wheels mounted on a rigid frame. It was built by French engineer J.N. Niepce and was the first ‘manpowered’ vehicle on wheels. Then in 1817, German nobleman Karl von Drais made a bicycle called the ‘Draisine’. This had handlebars and a front wheel that could be steered, so that the cyclist could change direction. Instead of pedals, the cyclist moved along by pushing with the tips of the feet. It had no brakes, which made it dangerous. In 1838 Scottish inventor Kirkpatrick Macmillan applied a system of gears to the wheels which were worked by the feet. But the modern bicycle was born in 1855, built by a young French workman, Ernest Michaux, who perfected Macmillan’s system by applying pedal directly on the front wheel. By 1860, the ‘michaudina’ had brakes. An important breakthrough came in 1896 when the first proper bicycle gears was patented by Englishman Edmund Hodgkinson . These enabled the cyclist to vary the numbers of spin...

  The Wheel is one of the most important inventions in the history of mankind. The earliest picture of a wheel dates about 5500 years ago and is seen on the Standard of Ur , a mosaic which depicts an ancient civilization in Mesopotamia (now Iraq) around 6000 years ago. The picture shows a procession of heavy war wagons rolling along on wooden wheels. These first wheels were solid wood and made of three pieces joined together with wooden struts or strips of leather. The two side pieces were shaped like a crescent moon and the central pieces had rounded edges with a hole through which the axle threaded so that the wheel could turn. These heavy, wooden wheels revolutionized transport, because they made the carrying of heavy and awkward materials so much quicker and easier. As the years passed, the spoked wheels were invented. The first spoked wheels appeared around 2000 B.C, and were used on Egyptian war wagons until 1500 B.C, making these faster and easier to drive. Before the wh...

  HELLO GUYS, I will be explaining to you how we know what the stars are made of. Each Star Produces its own individual light. By splitting the light in a spectrum, astronomers can discover the chemical elements in the star’s atmosphere absorb light of different wavelengths. Sodium atoms, for example, only absorb light from the yellow part of the spectrum, called an absorption line, tells scientists that there is sodium in the star. By studying the various lines made on the spectrum, scientists can determine what the star is made up of.