In the 1600s in Russia, the forerunners of present-day roller coasters were huge blocks of ice that were fashioned into sleds, with straw or fur on the icy seat for passenger comfort. Sand was used to help slow down the sled at the end of the ride to keep it from crashing, a technique based on the principle of friction. Later, more elaborate wooden sleds were built with iron runners to increase the speed and intensity of the ride.
Coaster historians diverge on the exact evolution of these ice slides into actual rolling carts. The most widespread account is that a few entrepreneurial Frenchmen imported the ice slide idea to France. The warmer climate of France tended to melt the ice, so the French started building waxed slides instead, eventually adding wheels to the sleds. In 1817, the Russes a Belleville (Russian Mountains of Belleville) became the first roller coaster where the train was attached to the track (in this case, the train axle fit into a carved groove). The French continued to expand on this idea, coming up with more complex track layouts, with multiple cars and all sorts of twists and turns.
The first American roller coaster was the Mauch Chunk Switchback Railway, built in the mountains of Pennsylvania in the mid-1800s. The track, originally built to send coal to a railway, was reconfigured as a “scenic tour.” For one dollar, tourists got a leisurely ride up to the top of the mountain followed by a wild, bumpy ride back down. Over the next 30 years, these scenic rides continued to thrive and were joined by wooden roller coasters similar to the ones we know today. These coasters were the main attraction at popular amusement parks throughout the United States, such as Kennywood Park in Pennsylvania and Coney Island in New York. By the 1920s, roller coasters were in full swing, with some 2,000 rides in operation around.
With the Great Depression and World War II, roller-coaster production declined, but a second roller-coaster boom in the 1970s and early 1980s revitalized the amusement-park industry. This era introduced a slew of innovative tubular steel coasters. Some of the most popular ride variations — such as the curving corkscrew track — saw their heyday around this time.
The first successful inverted coaster was introduced in 1992, and now you can find passengers riding in coasters with their feet dangling freely below them (and occasionally above them) as they circumnavigate the track. In 1997, a coaster opened at Six Flags Magic Mountain whose design would have been considered impossible even a few years before. This scream machine is 415 feet tall and can reach a speed of 100 miles per hour. Technology, working with the laws of physics, continues to push what is possible in ride design.
Sources: www.howstuffworks.com, www.learner.org