The starch facts about the tendency of our clothes to wrinkle in the dryer

Q. It’s been estimated that worldwide there are about 10 million species, but as yet fewer than two million of them have been classified. In what unexpected places might some of these unnamed species be found? A. Rather than trekking into the wilderness, try rummaging in the drawers of museums’ forgotten and neglected collections, where specimens remain “lost in time — until someone opens that drawer or takes the lid off a jar and sees something unknown inside,” says Christopher Kemp in “New Scientist” magazine. Perhaps as many as 75% of newly described species are already part of a collection somewhere on the planet.

Consider the size of the collections of just a few large, established museums: The London Natural History Museum: 10 million beetles filling 22,000 drawers; the American Museum of Natural History: 25,000 bats; the California Academy of Science in San Francisco: 300,000 reptiles and amphibians; Duke University herbarium in North Carolina: 160,000 specimens in the moss collection alone.

Yet the process of identification and classification is a painstaking one, with an average shelf life between collection and description (across all orders of organisms) being about 21 years. And even after a specimen is examined, it is often misidentified and wrongly named.

And now for the almost mind-boggling numbers: “All told, U.S. natural history collections contain an estimated 1 billion specimens. Across the world, the number probably exceeds 3 billion,” far too many to be accurately identified and named. Q. Tired of all that ironing? Why do clothes wrinkle anyway? And how does ironing work? What about wrinkle-free clothes? A. Plant-based fabrics such as cotton, linen, and hemp are mostly made of the natural polymer cellulose, whose molecules bond weakly with each other, says chemist Mark Lorch in “American Scientist” magazine. While the many bonds make the fabric strong, they continuously break and reform —especially in the presence of water, like in a washing machine — so the fabric tends to adopt whatever shape it has when it dries. If the fabric is scrunched up while it dries — like in a clothes dryer — the wrinkles are locked in. The heat and moisture of an iron quickly breaks the bonds, and the pressure gives the fabric a smoothness that gets locked in as the fabric cools and dries.

Now consider wrinklefree clothes: Starch is also a polymer but it’s branched in such a way that it stabilizes cellulose to prevent wrinkling. However, since starch is water soluble, it just comes out in the wash. So if you want permanently wrinkle-free clothes, you need non-water-soluble “starch” — the secret of wrinkle-resistant fabrics. Q. What can you learn from a whale’s giant earwax earplug?

A. Whale ears are largely sealed off from the outside, and over time, their earwax compacts into layers, forming a giant plug, reports Christie Wilcox in “New Scientist” magazine. As Baylor University mammal physiologist Stephan Trumble says, “We had one particular earplug that was 50 centimeters long and weighed about two pounds. And you can imagine the smell.” To estimate the whale’s age, “You can cut [the plug] in half and count the rings, like a tree.”

A careful sampling and analysis of the layers reveal a remarkable amount of information, including DNA sequences and stress hormone levels. “The data are kind

ABOUT THE AUTHORS

Bill is a journalist, Rich holds a doctorate in physics. Together the brothers bring you “Strange But True.” Send your questions to strangetrue@compuserve.com.