# 20-20: Ping-pong perks up peepers

Q. What's a fast, cost-free, pain-free way to improve your visual acuity? ­B. Bunny

A. Running a race may do it, say V. Gregory Payne and Larry D. Isaacs in Human Motor Development: A Lifespan Approach. Or going bicycling. Or even just 10 minutes of sustained table tennis. Studies show improved vision can last up to two hours after the exercise ends. "This increase in acuity is probably caused by the increased blood flow in and subsequent oxygenation of the eyes."

Q. What was the most ironic use of the new "radio and detection and ranging," developed in the 1930s by Robert Watson-Watt, who became known as the "father of RADAR"? ­G. Burghoff

A. The British Air Ministry had asked him about the possibility of concentrating enough energy in a radio beam to knock a plane out of the sky, says James Livingston in Driving Force: The Natural Magic of Magnets. Watson-Watt reported back that no, a radio death-ray was impossible, but it might be feasible to detect enemy aircraft using reflected radio waves. Thus the concept of radar was born.

The British quickly recognized the need for radar systems using higher frequency radio waves– microwaves for, greater accuracy. To do this, the "cavity magnetron" was developed and brought by British scientists to the U.S. for a demo. One American expert called the cavity magnetron the "most valuable cargo ever brought to our shores."

Nowadays radar aids air traffic control and weather surveillance. Less popular is another use that boomeranged on Watson-Watt as he hastened to a speaking engagement in 1954. As an anonymous verse at the time recapped it, "But now, by some ironic twist/ Radar spots the speedy motorist/ And bites, no doubt with legal wit/ The hand that once created it."

Q. How old are you? 1.Write down the number of the month you were born. 2. Double that number. 3. Add five. 4. Multiply the result by 50. 5. Add the current year. 6. Subtract 250. 7. Subtract the year of your birth. The last two digits in the answer give your age on your birthday this year. The first part is your birth month. What's the trick? ­S. Hawking

A. Amuse your friends with this one, then see if they can decode how it works, says California State Polytechnic University mathematician Laurie Riggs. In essence, since you add in the current year (step 5), then subtract the year of your birth (step 7), it should be no surprise your age is embedded in the final number. As for your birth month, let this be x (step 1). Double it to 2x (step 2). Add 5 to get 2x + 5 (step 3). Then multiply by 50, to get 100x + 250 (step 4). Later you subtract 250 (step 6), leaving 100x. The 100 just moves the x– which is your birth month– over to the left a few places to become the first part of your original answer. Shifty– and nifty!

Q. How is email changing our everyday discourse? BTW, technology has long influenced the way people talk. TTYL. LOL. ­A. Gore

A. "Running like clockwork" reflected the appearance of mechanical clocks in early modern Europe, says American University linguist Naomi S. Baron. Much later, Thomas Alva Edison borrowed "hello" from an old hunting call to signal to the person at the other end of a telephone line that a conversation was desired. At the time, telephone lines were always "on," and there were no ringers.

Today, email is contributing acronyms into the spoken word: "We were LOLing (laughing out loud) at Sara's joke." And into writings: BRB– "be right back." BTW– "by the way." TTYL–"talk to you later."

The newest form of computer-mediated communication is instant messaging (IM), already having subtle effects on the meanings of some words. From teens and young adults: "See you on AOL"– when, indeed, the participants won't see each other at all; "I'll talk to you on IM"– actually, sending each other written IMs; "I overheard your conversation"– meaning that "while you were composing an IM, I looked over your shoulder and read what you were writing."

"Such expanded senses are of course hardly unique to IM," says Baron, "as I learned from my blind roommate in college who always used to say, 'See you later.'"

Send strange questions to brothers Bill and Rich at StrangeTrue@Compuserve.com.

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