Ever wondered why it's so easy to rip the Collected Wisdom column out of the paper so you can store it away as a cherished keepsake? Read on.
THE QUESTION: Why, when tearing an article out of The Globe and Mail, is it possible to tear easily and virtually straight along the vertical edge, but impossible to do so horizontally? Louise Murgatroyd of Vancouver wants to know.
THE ANSWER: "Paper has a grain, much like wood," writes Marie Bannister of Saskatoon. "A sheet of paper torn parallel to the grain will be straight and against the grain will be jagged."
She says books, newspapers and magazines are printed with the grain parallel to the spine or centre fold to allow the pages to open more easily and lay flat. "It also won't crack the fibres every time the page is turned," she says, "although this would be more of an issue for books, since newspapers are not intended to be kept as long."
Several CW readers pointed out that paper is made from a slurry of wood fibres (called pulp) and the grain is created by the alignment of the long, slender fibres during manufacturing.
Ms. Bannister says the pulp is poured over a continuously moving, fine-mesh belt, which causes the fibres to line up in the direction the belt is travelling, thereby creating the grain. This remains after the water is pressed out of the pulp and the paper is dried.
Last week we cited the work of ant researcher E.O. Wilson in telling you that dead ants are carried away by their comrades because ants' corpses emit a chemical called oleic acid. Dr. Wilson even applied oleic acid to live ants and watched while their nest mates carried the "living corpses" off to the refuse pile.
However, Jocelyn Millar of the department of entomology at the University of California at Riverside says the story has evolved since the work of Dr. Wilson.
"We recently demonstrated with Argentine ants that the live ants have an odour that identifies them to other ants as being alive, so that they do not get carried to the refuse pile. When the ants die, this odour dissipates in an hour or so, and once this odour that says 'I am alive' is gone, then the other ants are triggered to carry the carcasses away.
"One problem with the original work implicating oleic acid," says Dr. Millar, "is that the researchers at the time used amounts … that were hundreds or thousands of times larger than would be found on an ant carcass, so the original experiments were seriously flawed and missed the 'odour of life' part of the story."
- Why are manufacturers of alcoholic beverages not required to provide nutritional information on their products? asks Andy Hayward of Montreal.
- "Sometimes I cannot remember a name or a fact when I am in conversation with someone," writes Jean Weihs of Toronto. "That name or fact will pop up in my head a day or two later." How and why does this happen?
- Eight-year-old Kostubh Agarwal of Winnipeg wants to know why we cry when we get hurt or injured.
Send answers and questions to firstname.lastname@example.org. Please include your name, location and a daytime phone number.