Inventions that changes the World

Carpentry

Before the discovery of metallurgy , long before plastics , the materials that Stone Age man used were those that he found around him in nature : stone , mud , bone , and of course wood. Wood is an extremely important material , having numerous useful properties ; it floats , it burns,  and it can be shaped relatively easily into a variety of different objects. The craft of shaping and using woo-carpentry- has its roots in prehistoric times.

Early woodwork consisted of the use of wood for basic tools, but there is also archeological evidence that Neanderthals were shaping wood into new forms as long ago as the middle Paleolithic ( Old Stone Age 300,000 to 30,000 years ago), using tools made from flint and stone. IN this way many useful things were created from wood , including fire-hardened spears and logs hollowed out to create simple boats.

By the Neolithic ( New Stone Age ), basic woodworking had evolved into a more complex craft-carpentry. The largely nomadic cultures of the Paleolithic era were settling down into more agrarian dwellings , and these were often constructed of timber. Researched Settlements in Japan and elsewhere include wooden houses of circa 5000 B.C.E.

The word carpentry actually derives from the Latin word carpentrius , which means maker of a carriage or wagon. Even in ancient Rome , however , carpenters different wooden products from weapons (bows , spears, and large rock-throwing machines) to beautifully crafted furniture.

Steam Engine with Separate Condenser

 Scottish engineer James Watt(1736-1819) was responsible for some of  the important advances in steam-engine technology. Steam engines had been in use since the 1710s, mainly to pump water from mines. These Machines depended upon steam condensing inside a large cylinder after the cylinder was cooled with cold water . AS the steam condensed , it took up less space , allowing atmospheric pressure to push down on a movable piston inside the cylinder.

In 1765 Watt made the first working model of his most important contribution to the development of steam power; he patented it in 1789. His innovation was an engine in which steam condensed outside the main cylinder in a separate condenser; the cylinder remained at working temperature at all times. Watt made several other technological improvements to increase the power and efficiency of his engines. For example , he realized that , within a closed cylinder , low pressure steam could push the piston instead of atmospheric air. It took only a short mental leap for Watt to design a double-acting engine win which steam pushed the piston first one way, then the other increasing efficiency still further.

Watt's influence in the history of steam-engine technology owes as much to his business partner Matthew Boulton (1728-1809)  , as it does to his own ingenuity. The two men formed as partnership in 1775, and Boulton poured huged amounts of money into Watt's innovations. From 1781, Boulton and Watt began making and selling steam engines that produced rotary motion; all previous engines had been restricted to a vertical , pumping action. Rotary steam engines were soon the most common source of power for factories , becoming a major driving force behind Britain's  Industrial Revolution.

Electromagnet

The fact that the current passing through a wire conductor produces a magnetic field around the wire , and that two current- carrying wires cold attract or repel each other depending  on the direction of the current , was emphasised in 1820 by the independent writings of Hans Oersted  and Andre-marine Ampere. (after whom the SI unit of measurement of electric current, the ampere , is named). It was, however , William Sturgeon(1783-1850), a physicist working at the Royal Academy , woolwich, London , who recognised the significance of the phenomenon. He converted electromagnetic device from toys into practical  weightlifting machines.

A horseshoe of iron around which is wound a loose current-carrying coil becomes a strong metal-lifting  device when the current is switched on and , just as important , the force disappears when the current is switched off. The action of the device can be speedily controlled by electricity. Electricity can flow down miles of wire , so throwing a switch in one place can activate a distant magnet to ring bell or move a lever. Joseph Henry (1797-1878) , while a professor of mathematics and physics at the Albany Academy in the United State , improved Sturgeon's electromagnet by insulating the wire and increasing the number of turns. His electromagnet lifted 2,300 pounds(1,040 kg), a world record at the  time . When Henry moved to Princeton, in 1832, he used an electromagnet as an electrical relay device to link his lab to his home. This was the first practical telegraph system. Henry, S.F.B. Morse, and Charles Wheatstone all insisted that they should be credited as the telegraph pioneer.

------ This horseshoe-shaped electromagnet belonged to the English chemist and physicist Michael Faraday.