Painting On Corn Starch (Or How to Have Fun with a Non-Newtonian Liquid)
A burst of scientific creativity struck in the kitchen. Notebook correspondent Betsy of New York had emailed us a chemistry.about.com recipe for making bouncy polymer balls from simple ingredients. Two of those ingredients were corn starch and water. Oh, we’ve combined those two before, said a member of The Naturalist’s Notebook’s Spontaneous Creativity Team. Another team member said that a mixture of corn starch and water, blended in the right ratio, takes on a bizarre texture—not exactly solid, not exactly liquid, and oddly plastic-like in its feel.
Out came a mixing bowl and a box of corn starch. The kitchen started to get messy. The white glop in the bowl quickly turned to an alien substance.
We made a 37-second video (click below) showing the strange not-liquid-not-solid quality of the corn-starch-and-water goo:
This mixture—sometimes compared to the sticky gunk called oobleck in the Dr. Seuss classic Bartholomew and the Oobleck—is what scientists call a “non-Newtonian liquid.” Isaac Newton posited that liquids flow at consistent, predictable rates. As the above video shows, the corn-starch-and-water glop does not do that. Why? Science Bob explains it this way:
“The size, shape, and makeup of the corn starch grains cause the corn starch to ‘lock up’ and hold its shape when pressure is applied to it. People have filled small pools with oobleck and they are able to walk across the surface of it (as long as they move quickly.) As soon as they stop walking, they begin to sink.”
Lest you think Isaac Newton didn’t know his laws of science, the mixture we’re discussing is more precisely described as a “suspension” of undissolved corn starch particles in water. That suspension will separate if left untouched and thus is not a pure liquid.
But we were more concerned with doing something creative than with defying the greatest genius in science history. We brought out little vials of food coloring and began making art. I’ll let the photos and captions tell the rest.
Though the art we created was ephemeral, like a cloud formation or an Andy Goldsworthy arrangement of leaves and flowers in a stream, there was a sense of creative freedom in the impermanence. And at the end, unlike during some painting sessions, the mess cleaned up easily with water.
We never did get to make the polymer balls, a science project of its own. But, as sure as Newton’s laws of motion hold true, we will.
Football (Part I)
The Carolina Panthers NFL team has announced that it is tweaking its logo to make its panther look more aggressive and contemporary. The trend in sports animal logos has been to make the creatures more fierce, usually with bared teeth and wild eyes. The changes in this logo are so subtle that they test one’s powers of observation.
In our relationship with panthers, of course, humans are probably the ones who should be portrayed as wild eyed and aggressive. The “contemporary” reality for most types of big cats is that they’re disappearing.
Bil Gilbert (1927-2012)
On January 27 the world lost a wonderful writer and nature lost an irreplaceable voice. My former Sports Illustrated colleague Bil Gilbert died at age 84, leaving behind many great friends and memories (see my own friend Bob Sullivan’s personal reminiscence: http://sportsillustrated.cnn.com/more/news/20120130/bil-gilbert/index.html) as well as a substantial journalistic legacy: from books such as Our Nature and How Animals Communicate to more than 400 magazine pieces for SI and Smithsonian. The Washington Post called him “our best full-time environmental journalist.” If you search the SI Vault for past stories, you’ll come across pieces that reflect how environmentally minded SI used to be. For example, one of Bil’s 1971 pieces was headlined WHO SEZ-Z-Z-Z-Z MAN IS THE DOMINANT SPECIES? CERTAINLY NOT THE WORLD’S 800,000 DIFFERENT KINDS OF INSECTS. DINING WITH GUSTO ON THE POOR OUTNUMBERED HUMAN AND LAUGHING AT HIS POISONS, THE BUGS PREPARE FOR THEIR FINEST HOUR—THE SUMMER, WHEN MANKIND MOVES OUTDOORS. In that age of a very different SI, Bil wrote about Tasmanian devils and disastrous Secretary of the Interior James Watt, and also did a 1973 SI cover story billed WOMEN ARE GETTING A RAW DEAL that had a powerful impact on the growth of women’s sports.
In addition to Bob Sullivan’s fine tribute, you might also read this one in, of all things, a newsletter devoted to track and field’s decathlon event. It too speaks of the wide range of people Bil touched in his life:
But you’d be best served by finding one of Bil’s pieces, or books, and enjoying the man himself.
Answers to the Last Puzzers
1) There are about 30,000 quills on an adult porcupine.
2) Light travels from the Moon to the Earth in just over one second.
3) It is true that the word halcyon, meaning a peaceful, happy period, comes from the Greek word for a kingfisher bird, which in Greek mythology was given the power to calm the weather and the seas while it laid its eggs.
1) What is the highest altitude ever reliably recorded for migrating butterflies?
a) 5,000 feet
b) 14,000 feet
c) 19,000 feet
2) Why was the shrub below given the name serviceberry?
a) Because it blossoms at a time when the ground has thawed enough to allow burial services
b) Because its blossoms were commonly used on trays in tea services
c) Because sprigs of it were given to soldiers for good luck when they were sent overseas