At Smithsonian, Sarah Zielinski notes the proverbial wisdom among some gardeners that watering plants on scorching hot days can start fires because droplets of water can focus light like a magnifying glass. Scientists decided to test this idea:
They started by placing small glass spheres on maple leaves and exposing them to sunlight. The leaves were quickly sunburned. However, when the glass spheres were replaced with water droplets on both maple and ginkgo leaves, there was no visible burn. Water drops are usually ellipsoidal in shape and are less able than a sphere to concentrate light. In addition, the ellipsoidal shape is able to intensify sunlight only when the sun is low in the sky—when the light is not so strong—and the water itself provides cooling.
There was an exception, though, with plants that have small waxy hairs covering their leaves, like floating ferns. The hairs are hydrophilic and water is held in spheres above the leaf’s surface. Like the glass spheres, these water droplets can intensify sunlight enough the burn a leaf. The scientists say that if water droplets accumulated on a parched plant, sunlight could theoretically spark a fire. They write, “however, the likelihood of this is considerably reduced by fact that after rain the originally dry vegetation becomes wet, and as it dries water drops also evaporate. Thus, claims of fires induced by sunlit water drops on vegetation should…be treated with a grain of salt.”
Link | Photo: US Department of Health and Human Services
A wattle is the bit of flesh below a rooster’s beak. What purpose does it serve? Carolynn Smith at Macquarie University in Australia conducted a study that suggests that it’s pure chicken bling. Sarah Zielinski writes in Scientific American about the results:
Cutting off the wattles of roosters and seeing how the behavior of hens changed wasn’t an option. Instead, Smith created four animated roosters. The animated roosters (see second part of the video below) all acted the same, performing the tidbitting routine over and over, and they all looked the same, except for their wattles. One had a normal wattle, one was missing his, a third had a wattle that didn’t move, and the fourth had an extra floppy wattle.
A test chicken would be placed inside a test pen with two “audience hens,” a couple of buddies intended to make the test hen more comfortable in the less familiar surroundings (fowl are social creatures). One of the videos was then played for the test chicken and her response was recorded: How quickly did she respond to the animated rooster? How quickly did she start searching for food (the normal response to a male tidbitting)? And how long did she search for food?
The test hens responded more quickly to the tidbitting males that had the normal or stationary wattles, less quickly to the one with the extra floppy wattle (the wattle moved so much that it swung up the side of the rooster’s head and appeared much smaller than it was) and slowest to the male lacking wattles. After the hen’s attention was gained, though, she reacted about the same to each of the four animated chickens. Smith suggests that the wattle helps a rooster gain a hen’s attention when he is tidbitting, rather like a human guy wearing flashy clothes while doing his best dance moves to try and pick up chicks.
Video at the link.
Link | Photo: U.S. Department of Health and Human Services
Sarah Zielinski writes in The Smithsonian that Jupiter, as the largest planet in our solar system, occasionally pulls comets into its orbit. Sometimes, as with comet Shoemaker-Levy 9 in 1994 (pictured), Jupiter’s gravity will even pull a comet into a direct impact. Zielinsky writes:
Astronomers from Japan and Northern Ireland, presenting their findings today at the European Planetary Science Congress, used observations of Comet Kushida-Muramatsu—from when it was discovered in 1993 and when it returned in 2001—to calculate the comet’s path over the previous century. They determined that the comet became a temporary moon when it entered Jupiter’s neighborhood in 1949. It made two full, if irregular, orbits around the planet, and then continued its travels into the inner solar system in 1962.
The researchers also predict that Comet 111P/Helin-Roman-Crockett, which circled Jupiter between 1967 and 1985, will again become a temporary moon and complete six loops around the planet between 2068 and 2086.
“The results of our study suggests that impacts on Jupiter and temporary satellite capture events may happen more frequently than we previously expected,” David Asher of Northern Ireland’s Armagh Observatory told the AFP.
Photo: NASA
Got
a neat story? Share it with the world by writing your very own Neatorama
blog post with the Upcoming
Queue. Who knows, you might just win something ... 
