Automobiles, also called cars, are the modern transportation mode that is most widely used in the world. They are usually powered by an internal combustion engine fueled most often by gasoline. They have four wheels and can seat one to seven people. They are a very important part of the global economy. The United States alone exports automobiles and their parts to 206 Countries around the world.
The scientific and technical building blocks for automobiles go back several hundred years. The earliest automobiles were steam engines attached to wagons in the late 1800s. These were very heavy and slow. In the early 1900s a new type of automobile, the internal combustion engine car, became popular. These were much lighter and faster than the earlier models. The internal combustion engine uses fuel, such as gasoline, diesel, or kerosene, to explode inside a cylinder and push down on the piston that makes the wheels turn. The energy of the gasoline or other fuel is transferred to the wheels through the transmission system. The car brakes use friction to stop the car. Some electric cars have regenerative brakes that use the electricity of the moving car to return some of the energy to the battery or generator.
In the 1920s, Henry Ford revolutionized automobile manufacturing by using assembly lines. This made it easy for him to produce many cars very quickly and at a low cost. This reduced the price of automobiles to the point where they could be affordable for middle-class families. The automobile has revolutionized modern life and made it possible for people to travel great distances in a relatively short amount of time. It has opened up opportunities for commerce, education, and recreation. In fact, it would be difficult to imagine or even think of modern-day life without the convenience of the automobile.
Despite their great advantages, the modern automobile is not without its problems. Some of these problems are the result of human drivers who make mistakes that can have serious or fatal consequences. Others are the result of tires that can lose traction when driving at high speeds. And, of course, crashes can happen, often with serious or even fatal injuries to the driver and passengers.
Automobiles come in a variety of shapes and sizes to meet the needs of different people and for different purposes. Some are designed for racing or traveling long distances. Some are designed to transport large amounts of cargo. And there are a variety of specialty cars such as fire, sanitary, and military vehicles that have special features to carry certain types of goods. Besides the passenger automobile, there are also the commercial automobiles which include the delivery van, utility truck, and mobile crane. There are also other specialized automobiles such as the snowmobile, infantry fighting vehicle, and timber carrier.
