At the speed of light

At the speed of light

It all started when Warren Fenton's curiosity about lasers was piqued
June 2, 2003

After years of witnessing their application and use everywhere—in science, medicine, recreation, and even pop culture—it became pretty clear to the 15-year-old high school student that lasers were not only part of everyday life, they were an important part of our future. But through all the flash and glitz, several questions about lasers nagged at him. How did they work? How could they be used in different applications? How did they react under various conditions?

Six months later, Warren's curiosity was piqued once again when Jim Strong, a friend and retired engineer, showed him his new lathing table and its simple interferometer—an optical instrument that measures the wavelength of light and can be used to measure very small distances. Warren—a grade 11 student at Paul Cain High School in St. Albert, a suburb north of Edmonton, Alberta—was determined to find out all about the instrument and how it's used for very precise measuring. After grilling Jim with endless questions, Warren realized it was time to see the light for himself. He decided to build his own interferometer.

Once it was ready, Warren decided to use his new interferometer to find out if the speed of light changed when it travelled in different gases. How would he do it? His device had two identical chambers through which a helium-neon laser beam was directed. One test chamber was kept as a vacuum. Into the second test chamber, Warren injected a series of gases one at a time: argon, nitrogen, helium, carbon dioxide, oxygen and room air (a mixture of gases). With each gas injection, a collector composed of a couple of phototransistors was used to determine the gas' effect on the speed of light.

Warren first experiment involved manually collecting his data. But in an effort to make it more efficient, he decided to automate the experiment. Through the ingenious use of a computer chip—which he programmed himself—the system became automated. What used to take up to two hours could be done in 15 minutes.

What did Warren discover as a result of his experiments? He determined that light does decrease its speed as it passes through a gas, and that this change in speed depends on which gas it passes through. Light slows down the most in carbon dioxide, oxygen, argon, and nitrogen. It slows down the least in helium.

To date, Warren's achievements have netted him a number of awards including: a Gold Medal (Intermediate Physical Sciences); the Canadian Association of Physicists award at the Canada-Wide Science Fair in 2002; an Honourable Mention for the E.H. Golan Physics Award; and Best Overall in Computers at his regional science fair in April 2003. When asked to shine a light on his future, Warren doesn't yet see things clearly. Despite an interest in engineering, he's leaving his education and career path wide open. And although he says all the attention surrounding his project is nice, he's staying focused on the big picture. "Awards are fleeting," he stresses, "but learning you have forever."