Here's a mid-winter question to ponder: What if, instead of freezing over, bodies of water froze under? That is, what if ice sank instead of floating?
Answer: We would all be dead.
Say what? Well, here's what would happen, according to marine geophysics professor Harold Tobin of the University of Wisconsin, whose Great Courses oceanography lectures Pamelia and I have been watching on DVD. In colder regions, crystals of ice would sink to the bottom of the oceans. Those oceans (and parts of others) would gradually freeze solid from the bottom up. Sea life would die. The Earth's climate would change dramatically. The planet would become, as Tobin puts it, "uninhabitable."
We're quite lucky that ice does float. Most materials are denser in solid form than in liquid form. If the oceans were made of molten iron, for example, a piece of solid iron would sink to the bottom. (We're particularly lucky that the oceans are not made of molten iron.) Water, however, forms a crystal structure and expands in volume by 9 percent when it freezes. That makes it less dense.
Why is ice so slow to form on the surface of the ocean? One reason is the churning of the waves, of course, but another reason is that ocean water is salty. Salt water freezes at a lower temperature than fresh water. Cold sea water (which is denser than warm sea water) tends to sink to the bottom before it gets cold enough to freeze.
By the way, if you lick a newly frozen piece of open-sea ice, it will taste salty, though over time, the pockets of salty brine will drain out. Glaciers and icebergs aren't salty; they're formed from compacted snow and ice. In fact, when Pamelia and I were doing a magazine travel story a few years ago, members of the cruise-ship crew took a small boat out and chipped off pieces of a glacier for passengers to put in their drinks. The super-hard glacial ice popped loudly as it released air bubbles that had been trapped inside for thousands of years. And yes, the ice floated.
Scientific Young Women
Studies have shown that in fourth grade, boys and girls are about equally interested in science. By eighth grade girls are half as likely to be interested. The decline has traditionally continued through high school and college, but that trend has been changing.
Today half the undergraduate science majors at MIT are women. So are half of the U.S.'s medical school students. As you may have noticed if you've visited The Naturalist's Notebook, we try to highlight women scientists and naturalists, in part because they still go unrecognized and in part because they are accomplishing so much.
Above is a video of a TED.com talk by the three student winners of the Google national high-school science contest. They are all young women. Their intelligence and poise will blow you away. You may not understand everything they're talking about (I didn't), but just enjoy the enthusiasm and curiosity that each one exudes. And if you watch long enough, you'll learn how to marinate grilled chicken in a way that makes it less likely to cause cancer. (If you watch the State of the Union address next week, you might see another young woman science whiz, who is a semifinalist in the Intel high school competition despite being homeless: http://www.huffingtonpost.com/2012/01/17/homeless-ny-science-whiz-invited_n_1210606.html)
I'm always delighted by the number of bright, ambitious, science-and-nature-loving young women who stop in at the Notebook. They don't feel limited by old stereotypes. Whether they're in grade school or grad school, they're ready to become marine biologists, doctors, astronomers, botanists and cancer researchers. They're eager to do things like save the world's tigers by developing advanced cloning techniques.
What sparks that strong interest in learning about the physical world and how it works? I've read a lot of interviews with scientists and naturalists of both genders that touch on why they followed their chosen course in life. Most mention an adult (frequently but not always a parent) who spent time with them doing simple things like looking through a microscope or a magnifying glass or walking through the woods studying bugs and leaves. A little time and a few words of encouragement can go a long way. It's interesting that decades later so many of those scientists and naturalists remain filled with the same childlike curiosity shown by the Google winners.
O.K., so girls certainly aren't the only smart kids. Last weekend 60 Minutes did a segment on an especially amazing 13-year-old boy named Jake who is a math and science prodigy. He is an honors student in college who gives credit to his autism (which often is linked with exceptional talent in a particular area) for his remarkable ability and drive. I'm guessing he would have done all right in the Google high school science fair...but he skipped high school, having taught himself the entire state of Indiana curriculum for grades 6 to 12 in slightly more than a year.
Birds and Bees
Timeout for a photo from our early 2012 pre-season preparations:
Chemistry in American Football
I say "American" football because, according to Facebook, The Naturalist's Notebook now has regular online followers from 18 countries, including India, Thailand, Poland, Lebanon, Indonesia, Greece, Chile and Saudi Arabia. In those and nearly all other countries "football" means soccer. Here I'm talking about American-style, helmets-and-pads, National Football League (NFL) football.
With only four teams left in the NFL playoffs, it's time for our annual analysis of who will win. Our method is unusual. We compare teams' quarterbacks by looking at the chemical elements whose atomic numbers match the players' uniform numbers. The atomic number is the number of protons in the nucleus of one atom of the element. (If not for a Nixon-era CIA cover-up, you would all know that "pro football" is actually short for "proton football.")
So here are this weekend's matchups. First, New York Giants quarterback Eli Manning (neon, element number 10) vs. San Francisco 49ers quarterback Alex Smith (sodium, element number 11). Except when he throws a touchdown pass, Manning seems quiet and unexcitable, much like neon, which is—surprise—the least reactive chemical element. But electricity (of playoff games) lights up Eli and brings out his best, as it does with neon when a charge is sent through a Times Square marquee sign. Sodium is, of course, best known as part of table salt, which in large doses can raise the blood pressure—the same effect Alex Smith's uneven play has had on 49ers fans over the years. In a big win last week, however, Smith showed another side of sodium: its explosiveness. In the description of esteemed science writer Theodore Gray, author of one of our favorite Notebook books, The Elements, "if you throw [sodium] into water, it rapidly generates hydrogen gas, which seconds later ignites with a tremendous bang, throwing flaming sodium in all directions."
Prediction: The sodium reaction seems a bit out of control, suggesting that Smith will throw too many interceptions. The neon glow signals a Giants victory.
The other matchup: Baltimore Ravens quarterback Joe Flacco (boron, element number 5) vs. New England Patriots quarterback Tom Brady (magnesium, element number 12). Don't underestimate boron, even it sounds bor-ing. In nature it's found in borax, whose grit can help wash off grime, and in combination with nitrogen, boron forms a crystal that is almost as hard as diamonds. Boron is a key ingredient, Theodore Gray tells us, that "gives Silly Putty its amazing ability to be both soft and moldable in your hand, yet hard and bouncy when you throw it against the wall."
The Patriots' defensive linemen hope to find Flacco soft and moldable in their hands when they grab him and throw him against the hard ground in Gillette Stadium, but to win the game their team will need its magnesium. Brady and element number 12 are both among what Gray calls "the truly marvelous structural metals." Magnesium-Brady is strong, reliable and—when ignited, because element No. 12 is highly inflammable—dazzlingly bright. The first photographic flashes were made by blowing magnesium powder into a candle flame.
Prediction: Boron will leave some deep scratches on the magnesium, but Brady and the Patriots advance to the Super Bowl.
One More Chemistry Joke
Add this to the list from our recent post:
Atom No. 1: "I've lost an electron." Atom No. 2: "Are you sure?" Atom No. 1: "I'm positive!"
Answers to the Last Puzzler
Here are the temperatures converted from Fahrenheit to Celsius:
1) 100 degrees Fahrenheit equals 37.8 degrees Celsius
2) 60 degrees F equals 15.5 degrees C
3) 10 degrees F equals minus-12.2 degrees C
1) Because we mentioned solid and molten iron earlier, here's a heavy metal question: Is the Earth's inner core—the Moon-sized iron-and-nickel sphere discovered in 1936 by Danish seismologist Inge Lehmann (yes, a woman), who was analyzing how earthquake waves traveled through the planet—liquid or solid?
2) NOT in commemoration of this week's birthday of Martin Luther King, Jr., I happened upon an ad for a bath sponge tastelessly called the Martin Loofah King. (Who comes up with these things?) More important, the ad got me thinking, where do loofahs come from? So here's your question. Is a loofah made from:
a) the inner bark of a cork tree
b) a Caribbean sea sponge
c) a fruit that grows on a subtropical vine