Steam Engine: Definition, Invention & History

The steam engine was one of the most important inventions in modern history. Steam engines helped to launch the industrial revolution, worked to propel trains across continents, and powered steam ships that navigated around the globe.

What Is a Steam Engine?

A steam engine uses heat and steam to create mechanical power. There have been many different types of steam engines throughout history; some using wood and others coal to generate the necessary steam. Most steam engines work by heating water in a chamber, which crates steam. The pressure of the steam can then be directed through pipes and valves to generate mechanical power.

Steam engines have been applied to a wide range of uses. The first steam engines were simple pumps used to remove water from mineshafts. After some improvements, more efficient and powerful steam engines were being used to power trains, ships, and entire factories.

Invention and Early History

The invention and refinement of steam engines played a central role in the development of the Industrial Revolution during the late 1700s and early 1800s in England, Europe, and North America. The Industrial Revolution was a period of rapid innovation in industry, transportation, and technology that was fueled largely through coal and steam power. Many of the advances made during the Industrial Revolution were thanks to the steam engine. But how did steam engines first come into use?

The earliest versions of steam engines were used to pump water from coalmines in England. A pump driven by a steam engine sat atop a mineshaft and burned the readily available coal to generate the power needed to remove water from deep in the shaft. Thomas Newcomen invented the first successful engine in 1712 in England, thus greatly increasing mining production. However, Newcomen's engine was inefficient and could only be used near coalmines, where coal was abundant and cheap enough to run the engine. If steam engines were to have wider uses, they needed to be improved.

A simple pump engine with steam piston on the right and pump on the left

The next major advancement in steam engines came in 1765 when James Watt introduced a refined steam engine that was more powerful and more efficient than the earlier engines used for pumping. The most important innovation introduced by Watt was that his engine used a piston to drive a wheel rather than a pump. Such a design opened the door for the Industrial Revolution as steam engines could now be used in a wide range of applications. By the early 1800s, steam engines had been further refined by other inventors and were small enough and efficient enough to power trains, boats, and entire factories.

Steam Engines and Transportation

When speaking of the Industrial Revolution, there is perhaps no better symbol of industrial and technological progress than the steam train. The first steam-powered trains were rather slow and inefficient and were only used to transport things like coal and iron between mines and factories. The first of these steam trains did not appear until 1804 in Wales. However, by 1825, the first public railway line was opened in England, and it was soon carrying both industrial cargo and passengers. Not long thereafter, rail networks spread out and connected most of the major industrial and population centers of England and Northwestern Europe. Trains had a tremendous impact in improving industrial output and accelerating the Industrial Revolution. Trains could transport large and heavy cargos over great distances at minimal cost.

A typical example of a steam train with coal car