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The Steam Engine

George Stephenson's Locomotion

The use of steam to move objects was invented by a Greek called Hero. Although making an object turn around Hero's invention had no real application at the time.

This first engine used steam which expands when heated in a boiler to raise a piston up and down in a cylinder.

In the 1700's steam was used to work pumps to pump water out of mines by an inventor called Thomas Savery. Savery developed the system whereby steam from a boiler filled a cylinder and was then allowed to cool down. The cooling turned the steam into a small amount of water but also left a vacuum in the container. The pressure of the vacuum was used to suck up the water from the mines.

James Watt an inventor at the time saw the potential of steam to drive vehicles. Models were made and James Watt's engines were set in motion in 1776. James Watt converted the up and down movement created in Thomas Newcomen's engine, with the use of a piston, into round and round movement. Watt's engines were used to power factory machinery and farm machinery. It was not until 1885 that George Stephenson developed the 'Locomotion Engine,'. This primitive engine made its first run on the Stockton to Darlington Railway.

Stephenson later went on to develop much more powerful engines such as the 'Blutcher' in 1814 and the famous 'Rocket' which reached speeds of 22 m.p.h running with loads as heavy as 12 tons and covering 14 miles in 69 minutes.

The power of steam was later used to run steam turbines. These turbines work in a similar way to a windmill. The steam which is under high pressure is directed towards the blades of the turbines which make them turn. The steam is then passed on to stationary blades which then direct the steam onto rotating blades. The steam expands as it turns the blades, this results in both the temperature and the pressure of the steam being lowered. The turbine can have three sets of blades that work at lower and higher steam pressures. In this way heat energy is transformed into a power that is able to move things.

Steam power is still used today. Thermal power stations, which burn fuel such as coal and oil use steam turbines to drive electrical generators.