A steam engine is a heat engine that performs mechanical work using steam as its working fluid. Using boiling water to produce motion goes back about 2000 years, but early devices were not practical. Since the late 1700’s steam engines have become a major source of mechanical power. The first steam-powered devices were used to pump water out of mines. In 1781, James Watt patented a steam engine that produced continuous rotative motion. These engines enabled a wide range of manufacturing machinery to be powered. These engines could be sited anywhere that water, coal or wood fuel could be obtained. Steam engines could also be applied to vehicle such as traction engines and railway locomotives. The stationary steam engine was an important part of the Industrial Revolution which lasted from the late 1700’s to the early and mid 1800’s. (Wikipedia)
The first steam engines operated on the ability of steam to condense back into liquid rather than on its ability to expand. When steam condenses, the liquid takes less space than the steam. If this condensation takes place in a sealed container, it creates a partial vacuum, or a pressure much lower than that of the surrounding atmosphere. Liquids and gases tend to flow from regions of higher pressure to regions of lower pressure, so when a vessel containing a partial vacuum is opened, the vacuum exerts a sucking action on whatever is on the other side of the opening. Thus, the partial vacuum and the surrounding atmosphere act together to perform work. (World Book, 881; Macaulay, 158)
“In 1698, Thomas Savery, an Englishman, patented the first practical steam engine, a pump to drain water from mines.”(World Book, 881) Savery’s pump had no moving parts other than valves operated by hand. These were turned to let steam enter a sealed vessel.
Cold water was then poured on the vessel to chill it and condense the steam. Then a valve was opened so that the...