Welcome to rehearsals for Collected Wisdom's spectacular production of The Sound of Music. Cue the Mother Abbess to sing Climb Every Mountain. And tell her she can't do it wearing mitts, a ski jacket and a tuque. Method actors are such a pain.
THE QUESTION: If heat rises, why is it colder the farther up a mountain you go? Beverly Jones Redekop of Chilliwack, B.C., wants to know.
THE ANSWER:
While warm air rises and cold air sinks, air temperatures are generally lower the higher you go, writes Roger Shaw, a retired professor of atmospheric science living in Lunenburg, N.S.
This is because "atmospheric pressure decreases with altitude [because] atmospheric pressure is the result of the force of gravity" acting on the atmosphere at various levels.
Over now to Paul Hackl of Toronto, who writes: "The farther up you go, the less dense the air becomes and so the farther apart the air molecules become. Since heat is stored by matter, the greater the distance between molecules, the less heat there is.
"The result is that as one ascends ... temperature falls at about one degree Celsius per 100 metres below the clouds (known as the condensation point). Above this point, the temperature falls by 0.6 of a degree Celsius per 100 metres. This is because the air is drier above the clouds and so holds even less heat. Water can hold a significant amount of heat," he writes. "Ever wait for a pot of water to boil?"
So, just because warm air rises, it doesn't mean it's going to stay warm.
Yes, indeed, says Alex MacPherson of Saskatoon. "The sun does not heat the atmosphere; instead, its rays heat the surface of the Earth which, in turn, heats the atmospheric slice nearest the ground." This heat does indeed rise, he says, but as it rises, it loses contact with the warm ground and is rapidly cooled.
FURTHER NOTICE
In response to our item last week on why saunas are lined with wood, Jack Gray of Ottawa writes: "Quite apart from the fact that Finland [where the sauna was invented] has lots of wood and wood is a poor conductor of heat, the main reason for using wood in a sauna is to raise the level of dry heat as high as possible. The sauna functions with dry heat, and wood absorbs the moisture that allows these dry heat levels to rise."
HELP WANTED
Why are national elections in Canada and the United States always held on a weekday, while in many other countries they are held on Sundays? Keira Rudge of Red Deer, Alta., wants to know.
Tony Abbott of Sarnia, Ont., says he has a new GPS navigation system. "I recently asked for the location of Indian restaurants in a city and, sure enough, the GPS led me to a good restaurant." Who supplies information about such things as restaurants and points of interest to the GPS manufacturers and who pays for it?
Send your questions and answers to wisdom@globeandmail.com. Include your name, location and a daytime phone number.
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