Mastering the Science of Surfing

By Ben Remo
Science Museum of Virginia Intern
 
One of the coolest sports during the hot months of summer may look like nothing more than a balancing act. However, there is a lot more to surfing than just staying up. To surf is to master the waves and motion of the water. Here, we explain the science behind one of the most popular summer sports.

The first thing any good surfer must know is how waves are formed. As wind gushes over the surface of the water, friction causes the water to ripple. How big the ripples become is dependent on the strength of the wind, the distance the wind blows (also known as the fetch), and the length or duration of the gust. Waves are broken up into many parts, necessary knowledge for any good surfer. The crest is the very top of the wave while the trough makes up the valley in between two waves or the lowest point. Wavelength is the distance between two waves and wave height is the distance between a wave’s crest and trough.Not all waves are good for surfing. It takes a little bit of science to make regular waves into surfer friendly ones. Surfers need waves that have a swell, or a smooth peak. These swells drag against the ocean floor, creating friction. This friction causes a wave to get taller and eventually break when they get close enough to shore. The best surfing waves are caused by a sand bank or reef on the ocean floor and by wind that blows from the beach out to the water. Winds that blow from the water to the beach cause choppy waves, the worst kind of waves for surfers. To catch a wave, the surfer must paddle to gain momentum, hopefully enough so that the wave accelerates him/her forward. Ideally, surfers should catch the waves just as they are breaking. At this point, the waves are at maximum velocity. To catch a wave, the surfer’s velocity and the wave’s velocity must be the same. When the board is being carried along by the wave, the surfer can stand up. Once the surfer has caught the wave, staying on the board becomes the problem.

Balance is the number one skill any good surfer can have. To stay up, one must find the center of gravity. On a surfboard, the center of gravity is usually towards the back. The surfer must straddle the center of gravity. It is important that the person’s weight be more towards the back or the front of the board will dip into the water and eventually flip. The surfer controls the motion and direction of the surfboard by shifting weight from one side to the other. The sport is both challenging and fun when done properly. We leave you with a couple of tips for safe surfing. First, never let the board get between you and an on coming wave. Always wear a leg rope connected to the board because a loose board is always dangerous. Wear something to protect your chest and stomach from board rashes. When you come up to the surface of the water, locate your board immediately. Always surf with a buddy or make sure somebody has your back. Lastly, have fun and be safe. Also, check out the film The Ultimate Wave Tahiti in the IMAX®Dome featuring professional surfer Kelly Slater.