The Calculus Diaries - Jennifer Ouellette [88]
Most acousticians have a touch of the daredevil in them, almost by necessity: If you’re trying to study the propagation of sound waves, you’ve got to go where the waves are happening, even if that leads you to remote Mayan ruins or the foot of an active volcano. Garces is no exception. When he’s not exploding missiles at the White Sands Missile Range in New Mexico to better study the infrasonic waves that result from the explosion, he’s setting up infrasound sensor arrays around volcanoes in Ecuador, or on Japan’s Kyushu Island. Once he was caught napping in a Toyota Corolla in the vicinity of a volcanic eruption, resulting in some harrowing, ash-choked moments before he was able to drive to safety.
So it’s not surprising that Garces is an avid surfer, along with just about everyone else in his Infrasound Laboratory (ISLA) on Hawaii’s Big Island. I have flown out to Kona to learn more about his lab, which is located right on the water’s edge, the better to collect data on incoming waves. While Maui is famous for its miles of sandy white beach, Kona’s shores are strewn with black lava rocks. The entire Big Island is the remnant of volcanic eruptions spanning thousands of years and is still home to active volcanoes. Locals like to place white shells against the black rocks to form pictures or spell out messages—Kona’s version of graffiti.
The lab is also near at least one prime local surfing haunt; lunchtime surf outings are a common occurrence. So it seems perfectly natural when Garces insists that if I really want to understand waveforms and wave dynamics, I should experience the phenomenon firsthand by hopping on a surfboard and hitting the warm Hawaiian water. I’m a strong swimmer, and I’ve always wanted to try surfing, so I jump at the chance. Everyone piles into various four-wheel-drive vehicles, and we trundle our way over unpaved rocky terrain to surfing paradise.
That’s how my pasty-white, city-dwelling self ends up on a borrowed surfboard in the bright sunshine, gamely paddling out to meet the incoming waves with the rest of Garces’ acoustical crew, along with his wife (a scientist in her own right) and young daughter. I do not, alas, remain pasty-white. By the end of the afternoon, my entire back is bright red, even the soles of my feet. I look like a haddock that has only been seared on one side.
Sunburn aside, there is a great deal of fundamental physics involved in the sport of surfing—potential and kinetic energy, surface tension, friction, buoyancy, hydrodynamics—and in the study of waves themselves. Waves are fundamental to nearly every field of physics, from water, sound, and light, to the wave nature of elementary particles and gravitational ripples in the fabric of space-time. Not to harsh anyone’s mellow or anything, but once again, wherever there is physics, there is also calculus.
BALANCING ACT
In 1778, Captain James Cook stopped off at Waimea Harbor on Kauai, en route from Tahiti to the northwest coast of North America in search of a fabled passage through that continent connecting the Pacific and Atlantic oceans. They were the first Europeans on record to visit the Polynesian chain, and their reception was warm and inviting, as they arrived smack in the middle of the season of worship for Lono, Polynesian god of peace. Islanders paddled out to where the HMS Discovery and Resolution were anchored to trade wares, so the ships could restock provisions. Cook returned after a year’s fruitless searching for the Northwest Passage to restock and make repairs to his ships. But this time, he ran afoul of the natives when he stopped at the Big Island—possibly because his second landing overlapped with their season of worship for Ku, Polynesian god of war.
Historical accounts differ about the details, but it seems the conflict arose when some of the natives began pilfering items from the ships. First there was a dispute concerning a stolen pair of tongs, and then one over a stolen boat. Cook’s men attempted to take a chief