Automobiles are vehicles that have four wheels and an internal combustion engine, powered most often by gasoline, a liquid petroleum product. They are one of the most universal of modern technologies, and automobile manufacturing is one of the world’s largest industries.
Having your own car gives you freedom from having to rely on others for transportation. However, a car can be dangerous if it crashes and hurts people. It can also cause air pollution if too many of them are used in a small area, and it is partly responsible for climate change. Many cities have public transportation such as buses, passenger trains and trams that can get you where you want to go more quickly and cheaper than an automobile.
People have been experimenting with cars for several hundred years. Some of the first were steam or electric, but they did not go very fast and required time to start. Karl Benz is generally credited with inventing the modern gas-powered automobile, but many inventors and engineers have made improvements since then. One of the most important developments came from Henry Ford who realized that using an assembly line could make automobiles more affordable to the middle class.
Most automobiles burn a fuel to power an internal combustion engine that turns the crankshaft to drive the wheels. The power from the engine is transmitted through a transmission system that can vary the speed of the wheels depending on the conditions. Most automobiles use gasoline, but they can also be powered by electricity, diesel, natural gas, or liquefied petroleum gases (LPG).