A trip to the amusement park wouldn’t be complete without a ride or two or three on a roller coaster. As businesses slowly begin to reopen after COVID-19 social distancing closures, theme parks may once again begin to welcome the public back for thrills and chills. In the meantime, future thrill-seekers can build up their bravery in anticipation. While you wait for amusement park gates to reopen, read up on these roller coaster facts.

Roller coasters are designed to give a person a seemingly close brush with danger through speed and hair-raising drops and flips. The Roller Coaster database indicates there are currently more than 2,500 roller coasters in the world. The first roller coasters were not the thrill-inducers found today at parks. The Switchback Gravity Railway, for example, which was a patented coaster that visitors to Brooklyn’s Coney Island could ride in 1884, faced riders outward. This was so they could enjoy a fabricated landscape scene while coasting at less than six miles per hour.

Many of the thrills associated with roller coasters are due to drops and dips from various heights. According to How it Works, changes in gravitational forces explain why the body, particularly the stomach, feels weird when riding a coaster. =

“When in freefall, every part of you is accelerating at the same rate, which gives you a similar feeling to weightlessness,” says Damien Arness-Dalton, from Science Museum. “There is no upwards force from the ground to cause your organs to be compressed, so they are floating inside of you, even though you are falling.”

This is new territory for the human body, so mixed signals are sent to the brain, indicating something is awry.

Gravitational forces affect how roller coasters are designed, too. Many extreme coasters have vertical loops. Roller coasters are teardrop-shaped instead of circular because, if they were circular, riders would be subjected to a force of 6-g on the body. That could cause blackouts, according to Gizmodo. The inverted teardrop shape helps to counter these high forces on the body.

Of course, speed and spins are not the only things that draw thrill seekers to roller coasters. Those who like the feeling of being in the clouds also enjoy reaching new heights. While many coasters inch riders up a steep incline gradually, “Kingda Ka” at Six Flags amusement park in New Jersey goes from zero to 128 miles per hour in only 3.5 seconds to speed riders up the rails 45 stories high at a 90-degree angle. At 456 feet in height, it’s the tallest coaster in the world.

Roller coasters are here to stay. When amusement parks reopen, chances are the lines to enjoy some hair-raising fun will be long.