This week, Collected Wisdom investigates aging voices and spiders' webs. If nothing else, you have to admit we're eclectic.
The question
Why does the sound of our voices change as we age? asks Gail Benjafield of St. Catharines, Ont. When talking to people on the phone, you can easily tell whether they're young or old. How come?
The answer
"As with everywhere else in the body, aging results in degeneration and atrophy within the larynx," writes Morton Doran, a professor of anatomy at the University of Calgary.
"The vocal cords in youth are relatively firm and very smooth; with age, they thin out and become irregular, and by not meeting together precisely … [they] change the quality of the voice," making it rougher.
As we age, he says, the voice loses, among other things, its range of pitch (from high sounds to low sounds). This is caused by muscles in the larynx becoming weaker, by degeneration of the cartilages that support the vocal cords and by degeneration of the joints that move the cartilages. Also, Prof. Doran writes, weakness in the muscles that control breathing results in less air being forced up between the vocal cords (this is what makes the cords vibrate to produce sound). Thus, less air reduces the strength of the voice.
Incidentally, CW has learned that older executives in Britain are undergoing "voice lifts" to make them sound younger. According to The Sunday Times, some aging bosses believe that their thin, reedy voices don't carry enough authority. The voice-lift operation involves removing fat from the abdomen and injecting it into the vocal cords to bulk them up.
The question
How do spiders connect their webs between trees? asks Don Holmes of Duncan, B.C.
The answer
There are two ways a spider gets from one point to another when spinning a web, writes Carla Hagstrom of the Gerstein Science Information Centre at the University of Toronto. "It can crawl from the starting point to the other spot, holding the silk thread clear of obstacles. Or it can play out a thread with a tuft of silk at the end, so that a breeze will carry the silk to another point of contact."
She says the spider can feel when the thread anchors on something. This thread then becomes the bridge of the web. "The spider reinforces the strand of silk by playing out additional thread as it travels across the bridge."
Further notice
Last week, we said acceleration rates for cars were stated as zero to 100 kilometres an hour or zero to 60 miles an hour because 100 km/h and 60 mph are common highway speed limits. Not so, says Jordan Schooley of Oakville, Ont. "Zero to 60 was actually introduced by Tom McCahill of Mechanix Illustrated magazine in the 1950s. After Mr. McCahill (considered the father of the vehicle road test) started tracking this statistic, others began to use it as well. "Then the car companies started to publicize it, and it eventually became the benchmark."
Help wanted
Are people born with a sense of direction or is it learned? Ursula MacKenzie of Winnipeg wants to know.
When you pull the tab on a can of Guinness, nitrogen inside a pressurized ball is released, causing the famous Guinness head to form, writes Paul A. Hallam of Toronto. How to they get the ball (and the beer) into the can without the ball exploding?