Archive for November, 2004

Seeing in the dark

November 24th, 2004 by dstmartin

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We’re going to peek into the dark places – night vision. Today on Engineering Works!

If you like action movies, you’ve probably seen night vision devices — goggles or telescope-like things that show you the bad guys in shades of green. They’re more than a Hollywood invention. Night vision devices – NVDs – really work. Troops in Afghanistan and Iraq use them every night.

NVDs use some high-powered engineering to turn dark into light. Let’s see how.
One way is called image enhancement. Image enhancement works like a radio receiver for light waves. This receiver receives little bits of light, so slight that our eyes can’t see them, and amplifies them the way a radio amplifies a weak signal — to the point that we can see what’s there.

The other is thermal imaging. Thermal imaging collects infrared light, light our eyes can’t see. We feel infrared light as heat instead of seeing it. Thermal imaging converts infrared light into images we can see.

The first night vision gear was used during World War II. It used a sort of infrared floodlight and special receiver to light up targets with infrared light. The equipment was bulky and heavy. And the images were hard to make sense of. Since then, engineers have made it lighter and easier to use, with sharper images.

We usually think of soldiers using NVDs. But police and rescue specialists use them, too.

We’ll see you later. Even if you’re in the dark.



November 17th, 2004 by dstmartin

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You’ve heard that sound thousands of times. It’s the barcode scanner at your local supermarket. Bar codes are everywhere. We’ll find out how they got there, today on Engineering Works!

In the supermarket, everything from corn flakes to hamburger carries that little label with the black stripes. And the supermarket isn’t the only place you’ll find barcodes. Libraries use barcodes to track the books on their shelves. Hospitals put them on the medications they dispense to patients.

The idea we know as barcodes isn’t new. Some engineering students came up with a primitive version back in the 1930s. But it took until the 1970s to get the system we know today up and running.

That strip of wide and narrow lines is actually numbers in disguise. Barcode readers translate the lines into numbers a computer can understand and link to a six-pack of soda or an antibiotic capsule. Other parts of the 12-digit number can be coded to represent individual brands. Coca-Cola’s number is 049000.

That simple-looking set of black lines can carry a lot of information. If you’re selling stuff in a store, the barcode can speed customers through the checkout line, tell the clerk the price and update your inventory. If you’re a nurse in a hospital, the barcode can confirm that you’re giving the right medication to the right patient and warn you if you’re about to make a mistake.

So keep an eye on that barcode.


Life’s a drag

November 3rd, 2004 by dstmartin

Sometimes life’s a drag. We’ll look into why, and what engineers do about it. Today, on Engineering Works!

Everybody likes to go fast. Whether it’s the hundred-yard, dash, or a hot car, or a jet plane, fast is good. But there’s a problem – when you go fast, the air gets in the way.

From the beginning of modern times, engineers have tried to figure out how to get through the air and go faster. It’s called aerodynamics. The word comes from two Greek words: airios – concerning the air – and dynamis – powerful.

When we hear the word aerodynamics, most of us think of streamlined airplanes. But it’s everything from runners at the Olympic games to that curveball that snaps off just out of the batter’s reach. Aerodynamics played a big role in Lance Armstrong’s win in the Tour de France.

Any time anything – a baseball or a bicycle – moves along, the air pushes against it. And it pushes harder the faster it moves. That push is friction, between the air and the surface of the object. Aerospace engineers call it drag. At high speeds, drag really puts the brakes on the need for speed.

Streamlined objects, such as rockets or bullets, are designed so that the air slips smoothly around them without a lot of friction – less drag. Engineers use aerodynamics to help airplanes go faster. And Olympic sprinters.

We’re going to sprint on out of here. Talk to you later.