Dimpled golf balls travel farther

Question: In golf's early days, why did weekend duffers outdistance aristocratic swingers in drives off the tee?

Answer: Because the affluent used smooth balls and routinely discarded them after the first signs of wear, says John Eric Goff in "Gold Medal Physics: The Science of Sports."

Other golfers settled for the used balls and before long noted that the ones with nicks and cuts went farther.

Today, based on myriad analyses by aerodynamic experts using wind tunnels, golf balls are made with dimples that simulate this roughened surface.

Without them, the 300+ yard drives (274+ meters) of pro golfers wouldn't make it half as far.

Though it might seem contradictory, balls with surface roughness experience LESS air drag than smooth ones, something not really understood until the turn of the 20th century.

Because of the greater surface friction on the spinning ball, a "boundary layer" of air forms that keeps incoming air from reaching the ball's surface.

In fact, most sports balls have some type of surface imperfection, such as the prominent stitches on a baseball or football.

"It's doubtful that the first person to stitch up a baseball had fluid mechanics in mind.

But were it not for those wonderful 108 double stitches on a baseball, home runs in today's parks would be almost nonexistent."

Question: Estimating animal populations is tricky, in part because different species require different methods.

What are a few of these?

Answer: In the case of blue whales, biologists tally the number spotted along a stretch of ocean, then extrapolate to larger populations, says "Science Illustrated" magazine.

With the mark-release-recapture technique, they "mark" whales by photographing them, then estimate the entire population from the ratio of marked to unmarked whales in a later census.

Latest count: 6,000.

African elephants are counted from the air, though some can be missed, especially in forested areas.

So researchers supplement aerial surveys by estimating dung density for a designated area, even using DNA samplings to compile lists of individuals.

Latest count: 550,000.