Archive for August, 2006

White House

August 30th, 2006 by Gene
White House
 

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The White House in Washington, D.C., is the capital’s number-one tourist stop. We’ll take a look at a White House tourists never see — today, on Engineering Works!

When you see the White House today, it’s easy to forget that 50-some years ago, it was on the brink of falling down around President Harry Truman’s ears. His daughter’s piano had punched a hole through her bedroom floor. Ceilings sagged. The whole second floor was ready to drop onto the first floor. About the only sound part of the building was the sandstone exterior walls.

So in late 1949, workers began taking the interior of the White House apart, piece by piece. Doors, windows, mantels and other important architectural pieces were removed and tagged to be put back again, exactly where they had been.

Engineers designed a whole new interior, supported by a massive concrete and steel framework. Bulldozers dug two deeper levels below the existing basement. They dug 126 pits for concrete pillars to support the walls. The important rooms on the first floor were restored to the condition they were when the White House was new. From the outside, you couldn’t tell the whole inside had been taken out and rebuilt.

Three years and four months later, Truman and his family moved back into the White House. Today, you’d never know the inside of the building is 150 years newer than the outside.

We’ve done this week’s renovation. See you next time.

EngineeringWorks! is made possible by Texas A&M Engineering and produced by KAMU-FM in College Station. We’re on the World Wide Web, too. Visit us at engineeringworks.tamu.edu.

Electric Guitars

August 16th, 2006 by Gene
 

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We’re going to listen to the music. Today, on Engineering Works!

Guitars, especially electric guitars are an important part of modern popular music. Imagine the Beatles without George Harrison’s guitar. Or Jimi Hendrix without distortion. Electric guitars made it work.

Guitar players started experimenting with electricity to amplify their instruments during the 1930s, when big band swing was big. The guitar was getting lost in all that brass.

The first pickups for guitars were pretty simple – a magnet the size and shape of a tube of lipstick wrapped lengthwise with wire. Simple, huh? But basically, that’s it.

Here’s how it works. The magnet is surrounded by a magnetic field. Think elementary school science class: Iron filings; a magnet; and a sheet of glass.
Put that wire-wrapped magnet under the steel strings of a guitar and you’re ready to go. As the strings vibrate, they disturb the magnetic field and create a small electric current in the wires wrapped around the magnet. Feed that tiny signal into an amplifier and you’ve got the sound that made electric guitars with names like Fender, Gibson and Rickenbacker famous.

The sound those early pickups produced wasn’t that great. They tended to pick up noise from room wiring, too, but they worked. And engineers and musicians have made them lots better over the years, since. The pickups on today’s guitars provide cleaner, stronger sound, but they’re still basically magnets and wire.

It’s time to wrap up this gig. See you later.

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