New Heights for the Olympic Torch

DEBBIE ELLIOTT, host:

Chinese officials announced today that 21,880 torchbearers will carry the flame for the 2008 Olympic Games in Beijing. Among them will be mountain climbers who will have the honor of carrying the two-foot tall propane torch to the peak of Mt. Everest. If getting up the mountain weren't hard enough, there's another challenge.

Mr. JERRY BELL (Senior Scientist, American Chemical Society): Since we're going up Everest, the torch has got to survive the cold, which will be in the neighborhood of let's say, zero Fahrenheit, winds, which could reach gale force.

ELLIOTT: And the thinnest of air. How will the flames survive? That's the question for today's Science Out of the Box.

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ELLIOTT: Jerry Bell is a senior scientist with the American Chemical Society.

Mr. BELL: You have to have three elements to produce a fire - a fuel, an oxidizer and some oil igniting the fuel and oxidizer.

ELLIOTT: Your standard torch works when the fuel mixes with the surrounding air and is ignited by a match.

Mr. BELL: That's what's called, usually called the diffusion flame because the air, the oxygen has diffused into the flame from outside. The other kind of flame is a pre-mixed flame, and that's what you get in a Bunsen burner where the fuel and the air, the oxygen in the air are mixed before they get to the flame.

ELLIOTT: Bell says that most modern Olympic torches use a combination of the two types of flames. They have a pilot flame, which runs on fuel that's been pre-mixed with oxygen, so they stay lit. But is anyone with an old-fashioned gas stove at home knows a pilot light burns low and blue, not very photogenic for the crowds watching on TV.

So part of the Olympic torch's fuel is diverted to a spot just above the pilot flame. When this fuel ignites, it burns a luminous yellow as it interacts with the surrounding oxygen. This kind of torch works in most altitudes, but on Everest where the air is rare, there may not be enough oxygen to keep even the pilot flame alive.

So like the mountain climbers themselves, the torch may need its own oxygen supply. And engineers at the China Aerospace Science and Industry Corporation are still testing different systems to see what will work on the mountain. But then there's the question of wind, and why if it contains oxygen, does it sometimes blow out a flame. For one, it can lower the temperature too much, and also…

Mr. BELL: What wind can do is simply drive the fuel away by pushing it away from the flame. No fuel, no flame.

ELLIOTT: And in its current design, the Olympic torch is built to withstand 40-mile an hour winds, not the 100-mile an hour howlers that it might encounter on Everest. So Chinese engineers have their work cut out for them but they won't be the first to test the limits of a torch.

Mr. BELL: Oh, certainly the most trying one was underwater at the Great Barrier Reef for the Australian Olympics. They have to rig the torch for that one. They've used a flare, basically, an underwater flare. But that's probably the most strenuous conditions that anybody has tried.

ELLIOTT: Jerry Bell is optimistic the Chinese will come up with a torch that's up to Everest, and the Chinese are, too. They have even covered the 2008 torch with a pattern of red squiggly clouds, a symbol of luck that seems well suited for summiting the world's mightiest peak.

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