The Steam Engine

The Steam Engine

An Invention That Changed the World For thousands of years, people used their muscles for work. They also used animals to help them. In the 1700s, the invention of the steam engine changed everything. People began to make fewer goods by hand. Instead, they used machines. Many of those machines were powered by steam.

What Is Steam? Have you ever watched someone boil water in a pot on the stove? Sometimes you can see a little cloud above the pot. That's steam. It can only be seen when it hits cooler air. Steam is a gas. People make steam do work by boiling water. They heat up the water in a gigantic pot called a boiler. They make the boiler hot by burning fuel, such as coal. Burning coal becomes hotter than the top of a stove-a lot hotter! The heat boils the water and makes steam. Steam takes up more room than liquid water. As the steam expands, it pushes the moveable parts of a machine. The movement of those parts creates power.

The First Real Steam Engines Almost 300 years ago, in 1712, Thomas Newcomen built a steam engine. Others had built steam engines, but Newcomen's was the first to work really well. He used his steam engine to run a water pump, which pumped water out of coal mines. Miners could then reach more coal. The engine had one problem. It needed a large amount of coal to do a small amount of work.

Steam Engine Improvements In the 1760s, Scotsman James Watt improved Newcomen's engine. He made the machine work with less coal. Watt also made other kinds of steam engines. He made one called the rotary (circular) steam engine. It could run all kinds of machines. This invention was one event that led to the Industrial Revolution, also known as the Age of Steam. The Age of Steam brought new ways to do work and new ways for people and goods to travel.

High-Pressure Steam Engines At the beginning of the Age of Steam, Watt's steam engines used low-pressure steam. His steam engines were big, and they operated, or worked, slowly. Watt knew he could make smaller and faster steam engines. But he would have to use higher-pressure steam. He was against that idea. Higher pressure could cause a boiler to explode. An explosion could injure or kill people.