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The Straight Dope 

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My grandmother used to amuse me by making five-pointed stars from a piece of paper. She'd fold it, make one cut, then hand it to me to unfold. The stars had five points, and the angles were all even. How did she do this? I'd ask Grandma but she died last year and won't respond to the Ouija board. --Katharyn Bine, Reston, Virginia

The Straight Dope, the column with something for everybody. For this one you can thank Mrs. Adams, who's always been handy with sharp instruments:

Step 1. Fold a piece of paper in quarters, then unfold it again as shown.

Steps 2 through 4. Fold up one corner so angle A is double the size of angle B. You'll have to do this by eye but you can check by folding angle A in half, then folding the whole thing over on angle B. They should all be the same size.

Step 5. Unfold one of the folds of angle A as shown.

Step 6. Fold up the opposite corner C so it meets the edge of A.

Step 7. Fold along line D so that A lines up back-to-back with C. They should be exactly the same size. You should wind up with something that looks like the drawing. Now cut line E so that it bisects angle FG. Unfold. Voila, a star is born.

Why do old black-and-white movies and newsreels move so fast? With our modern technology, can't we slow them down to make them look normal? --Karl M., Richardson, Texas

Easier said than done. Most silent movies were shot at 16 frames per second, about the fastest you could manage in the early days and still have a quiet, reliable projection machine. When shown, the film flickered annoyingly but the action moved at normal speed. (Usually. It's said Charlie Chaplin had his cameras run slower than normal to produce a comical speedup when the film was projected.)

With the advent of sound in the 1920s the industry switched to 24 frames per second, which by then had become practical. Apart from ending flicker, the higher speed was needed for better sound quality. When old films were run through the new projectors the action sped up 50 percent.

Today it's possible to produce flicker-free, normal-speed versions of the old silents through a process known as stretch printing, in which every other frame is printed twice. The result is slightly jerky but watchable and has been used in contemporary films to achieve a period feel. But it's tedious and expensive and many film labs hate to do it, so it's mostly reserved for special projects. Just as well. The Keystone Kops wouldn't be nearly as funny at normal speed.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

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