Concentration
Question: People doing a tricky job will stick their tongue out and clamp it
between their lips. Why? Does this happen in all cultures?
Answer: When you need to concentrate on something, say a word problem, you
are using the hemisphere of the brain also used for processing motor input. It
is amusing to see people slow down when they are thinking of something difficult
while walking. This is caused by interference from the two activities fighting
for the same bit of brain to process them. I suppose by biting your lip or
sticking your tongue out, you are suspending motor activity and also keeping
your head rigid, to minimise movement, and hence interference.
Melanie Western
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Answer: Large areas of the brain are devoted to control of the tongue and to
the receipt of sensation from it.
Perhaps with the tongue held rigid against the teeth or lips, the activity of
those areas is subdued, allowing delicate tasks like threading a needle to
proceed with less interference.
Barry Lord
Rochdale, Lancashire
Aaaaaargh
Question: People鈥檚 hair is sometimes reported to have turned white overnight
as a result of shock. Can white hair be the result of shock and, if this is so,
how long might it take? What is the process involved?
(continued)
Answer: In more than 50 years of medical practice I never saw instant grey or
white hair.
However, since I have retired, a neighbour (a French farmer, about 45 years
old) whom I know well went from black to totally white in less than 14 days.
There was no shock and he was a perfectly healthy working man. There were also
at least 100 witnesses and there was no question of dyes. The farmer was very
embarrassed by the situation. He remained white as snow for about six months and
then over a period of about four months grew back to full black.
Douglas Nelson
Averon-Bergelle, France
Out of puff
Question: I have recently given up smoking and have developed a very sore
throat. Talking to other ex-smokers has revealed that they were afflicted with
an increase in respiratory ailments when they gave up. More bizarrely, a friend
reported suffering from excessive flatulence on quitting. Why, when you finally
stop abusing yourself with nicotine, do you suffer from symptoms that you didn鈥檛
previously experience?
Answer: A sore throat, respiratory ailments and excessive flatulence are
common symptoms of recovery after stopping smoking. Once exposure to the more
than 4000 chemicals present in tobacco smoke stops, the body strives to return
to its pre-smoking state. It is thought that a smoker has a constant sore throat
caused by the inhaled chemicals, but that the pain is felt only after removal of
the nerve-damaging toxins. Likewise, the cilia (hairs) in the respiratory tract
regrow and allow waste matter to be once again removed by coughing.
Smoking speeds up the movement of food through the gut (to the smokers鈥�
nutritional detriment), so while the body readjusts after stopping smoking, some
fermentation can take place鈥攃ausing excessive flatulence. Amazingly, the
body can adapt very quickly, even after years of smoking.
Finally, nicotine on its own is not responsible for health problems. The real
villain is the poisonous gas carbon monoxide, which combines with haemoglobin in
red blood cells, reducing the blood鈥檚 capacity for carrying oxygen by as much as
15 per cent.
Jane Roberts
Poulton-le-Fylde, Lancashire
Answer: In smokers, the function of cells and structures in the lining of
their throat is depressed by the smoke. For example, the cilia no longer waft
mucus about. However, when a person stops smoking, these normal responses
return, producing an increased sensitivity and consequent inflammation, soreness
and coughing. This normally takes at least a year to clear effectively.
In regular smokers the nicotine stimulates the sympathetic nervous system,
causing quickening of the pulse, raised blood pressure, impaired appetite and
impaired digestion. Therefore, when someone stops smoking, appetite and
digestion levels rise, leading to an increase in acid secretion and consequently
an increase in gas production鈥攊n other words flatulence. It is also common
for those who give up smoking to put on weight.
However, considering the benefits of giving up smoking these short-term
problems are a small price to pay, however noisy they may be . . .
Alan Robertson
Edinburgh
Long-distance cone call
Question: As a child in New Zealand, I was told that the Krakatoa eruption in
Indonesia was heard in Auckland. (At the time, the sound was allegedly
interpreted as the Russian Navy having a spot of artillery practice.) By what
mechanism could the sound of the eruption remain audible after being transmitted
for several thousand kilometres?
(continued)
Answer: I would like to correct a detail in the answer of a previous
correspondent. A temperature inversion is when cold air is found below, not
above, hot air. This means that the speed of sound is faster at higher altitude,
and for this reason sound tends to curve downwards instead of upwards. The
reason this is called an inversion is that the temperature usually drops with
increasing altitude.
Eric Kvaalen
Qiryat Bialik, Israel
This week鈥檚 questions
Ear ear: I have just been discharged from hospital and while I was there the
nurses measured my temperature by pressing what looked like a small nozzle onto
the skin of my ear. A reading to an accuracy of 卤 0.1 掳C was
obtained in about 1 second. How does this work?
Philip Woodward
Malvern, Worcestershire
Steel stealer: For Christmas I received a very useful kitchen gadget. It
appears to be made of stainless steel and is shaped like a flattened egg. It
would also seem to be hollow, judging by its weight. This gadget claims to
remove all manner of odours from the hands, such as onion, garlic and white
spirit, that are not generally removed with soap and water. To use it you rub it
all over your hands and between your fingers, under cold running water. I have
now tested it out after handling several things, including all the above, and it
does work. How?
Alison Woodhouse
Bromley, Kent