Archive for December, 2004

Fuel cell cars

December 15th, 2004 by dstmartin

Listen to the episode

Hop in. We’re going to take a ride in a car some experts say could be the car of the future, today on Engineering Works!

The first thing you’ll notice about our ride is that it’s quiet. All you hear is the tires on the pavement and … nothing. It’s quiet. No engine noise. That’s because the motor turning our wheels is electric. Not a gas tank or fuel injector in sight. The power comes from something called a fuel cell that uses hydrogen, a gas that’s the most abundant fuel in the universe, to produce electricity. No fossil fuels; no gasoline shortages; no smelly exhaust.

The idea behind fuel cells has been around for a long time. Since 1839, long before gasoline and long before automobiles. Fuel cells helped power NASA’s missions to the moon, but engineers have only recently begun to think about using hydrogen and fuel cells to power cars and provide electricity for our homes.

Here’s how they work. Hydrogen enters the fuel cell, a sort of gas-tight can, and a chemical reaction takes the atom apart. One part actually becomes an electric current that’ll run an electric motor. Dump what’s left into the atmosphere and you end up with good old H2O, water. No noxious exhaust fumes.

We might have fuel cells in our future. We’ve got a long way to go before they’re really practical: where to get hydrogen cheaply and easily; building a network of hydrogen filling stations; what to do with the leftover water. But engineers are working on it.

Well, gotta go.


Where rubber meets the road

December 8th, 2004 by dstmartin

Listen to the episode

There’s more to making tracks than meets the eye. We’ll look at tires today on Engineering Works.

Most of us don’t think about the tires we’re riding on until we have to. Tires do more than get you from here to there. They need to hug the road in turns and sudden stops, on wet roads and dry. That’s where tread comes in.

Tread is the part of the rubber that hits the road. But that sporty tread on your tires does more than make your car look cool. Engineers design tread patterns to improve traction – how tires grip the pavement. Traction keeps your car from sliding when you turn that corner a little too fast. It keeps you from getting stuck in snow and mud.

The right tread can even help keep your car from hydroplaning in heavy rain or water on the highway. Scary. What happens is a wedge of water builds up under rolling tires and lifts them off the road and then you’re in trouble.

Tread designs with center channels and slanted grooves – often V-shaped – flush water out the back and sides of the tire so you can steer and brake safely.

But tires in even the best condition can’t do their job unless you drive sensibly. Drive too fast, and those grooves can’t push the water out quickly enough. So slow down on wet roads!

Well, it’s time to make our own tracks and head for home.


Dirty bombs

December 1st, 2004 by dstmartin

Listen to the episode

We’re going to look into one of the threats that make terrorists terrifying – dirty bombs. Today on Engineering Works!

Only a while ago, terrorism was just a word. Now it’s something everybody knows about — car bombs, hijacked airliners, anthrax in the mail. One of the scariest threats is something called a dirty bomb. Dirty bombs are bombs that scatter radioactive material around where they go off. They’re not nuclear bombs. They’re not weapons of mass destruction. They’re weapons of mass disruption.

Unless you’re near the explosion, your chances of getting seriously hurt by one are pretty small. It’s important to understand that. Dirty bombs are not nuclear bombs. Compared to real nuclear bombs, dirty bombs are firecrackers.

But they are easier to build than nuclear bombs – lots less engineering. That’s what makes them so scary. All you need to make one is some explosives – one stick of dynamite would do for a small one – and radioactive stuff. The most likely stuff is radioactive material hospitals use for nuclear medicine or the radiation sources industry uses for all sorts of things. It’s easy enough to get to be concerned about.

The people in the most danger from a dirty bomb are probably the fire and rescue personnel who treat people injured in the explosion and clean up afterward.

Don’t get us wrong. A dirty bomb is a serious thing. But it’s a long way from a major disaster.