July 1, 2007 — Basic physics can explain how skateboarders are able to do those amazing tricks and why some are impossible. Newton's Laws of Motion explain everything from transferring energy through your body to build speed to manipulating the board's center of gravity to keep it attached to your feet in the air.
Skateboarding is the third most popular sport with teenagers, but learning to balance on a board with wheels isn't easy.
Amateur skateboarder Corey Rubin makes skateboarding look easy, but it's not a simple sport to master. "You have to be tenacious, you have to keep on doing it, and you'll get frustrated," Rubin says.
To help skaters feel less frustrated, physicist from the American Physical Society and life-long skater, James Riordon, teaches a few basic principles of science that can help skaters of all levels conquer a few fundamental moves. "Knowing a little about the physics of skateboarding can really help you understand what's possible and understand why things didn't work out," Riordon says.
In a basic move called pumping, the body is used to gain speed without the rider's feet leaving the board. "What you're doing is you're turning your body into a type of physical instrument that allows you to put energy back into the ride," Riordon says.
One of the most well-known tricks is the Ollie. It was invented in the 1970s by Allan "Ollie" Gelfand. It's a maneuver from which most skateboard tricks are based upon and is used to get the board off the ground without touching it. A skater pops the board up in the air, causing the center of gravity to rise, then hits the other end of the board, leveling it out. It creates the illusion that the skater's feet are glued to the board in mid-air." Particularly, when you see people do some of these incredibly challenging tricks, that even to me look like they defy physics, I have to watch it a few times to understand how these things are even possible," Riordon says.
A little skateboard science can help even advanced skaters improve their game and keep coming back. "I want to keep excelling; I want to accomplish a lot more tricks," Rubin says.
The American Association of Physics Teachers and the American Physical Society contributed to the information contained in the TV portion of this report.
BACKGROUND: When it comes to skateboarding, there's a lot of physics involved. Having a basic understanding of physics can help you learn skateboarding tricks a bit faster. You can calculate whatýs possible if you practice enough, and what kinds of moves are impossible because of the laws of physics.
FORCE OF GRAVITY: Skateboarders rely on gravity to supply the force needed to get them moving. They push off the ramp's ledge. Gravity pulls on the board and they accelerate down the ramp. The faster a skateboarder goes, the higher he can fly when he launches off the ramp's opposite side. More height means more time to execute tricks, resulting in more points from the judges. The taller the ramp, the more gravitational potential energy will be stored when the skateboarder is at the top. Skateboarding half-pipe ramps are typically 15 feet high. All that potential energy converts into kinetic energy on the way down. The kinetic energy gained is converted back into potential energy as the skateboarder shoots up the opposite side of the ramp.
TURN, TURN, TURN: Skateboarders make turns by 'carving': leaning their weight on their toes to push that side of the board into the ground, causing the edge of the board beneath their heels to pop off the ground. Pushing against the ground on the left will produce an equal and opposite reaction to the right, just like Newton's third law of motion says. The more force you exert on one side of the board, the greater your acceleration will be in the direction of that force. So the more a skateboarder leans to one side, the quicker he (or she) will turn in that direction.
STICKING IT: The biggest challenge is to keep the skateboard near your feet at all times, even though you're not strapped in, as you would be in snowboarding. The secret, once again, is Newton's third law of equal and opposite reactions. When a skateboarder reaches the far side of a ramp, he stomps down on the tail end of the board. The ramp will respond with an equal and opposite force, pushing the board off the ramp and into the air. Even in midair, the friction from the shoe soles and the upward push of the skateboard will keep the board close to his feet.
Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.
Share
Blog
Print
Email
Bookmark
