真的太久沒PO文，功課真的太多了......
Title: Life in Antarctica Can be Very Boring.
Don’t be too jealous. Some scientists can check out chicks’ butts all day. Two polar scientists, Victor Benno Meyer-Rochow and Jozsef Gal, were amazed by how fast and how far penguins can project their feces, so they started penguin poop research. The result was published in Polar Biology, one of the leading scientific journals covering research at the poles, and was titled: Pressures Produced When Penguins Pooh--Calculations on Avian Defaecation. In the introduction of their paper, they claimed: Anyone who has watched a penguin fire a “shot” from its rear end must have wondered about the pressure the bird generates…… So I looked up a clip on YouTube and was truly stunned by the speed and power. The penguin jetted out white liquid horizontally on the rock wall and a little of it even splattered back. In that sense, the regulation that humans must not approach penguins closer than five meters is probably set up for protecting humans. Compared to observing penguins poop from a distance, the calculation is not that difficult. The approximate pressures can be calculated if the scientists know the following three conditions: First, distance the feces travels before it hits the ground; Second, density and viscosity of the material; Third, the shape, aperture, and height above the ground of the cloaca. Chinstrap and Adelie penguins were the two species that Meyer-Rochow and Gal observed. As they described in the paper, when a penguin wants to poop, in order to keep its nest clean, it leaves its stony nest, moving to the higher edge of it (about 20cm higher than the ground), standing up, turning its back nest-outward, bending forward, lifting its tail, and shooting. The expelled material hits the ground about 40±12 cm away from cloaca, and it looks whitish or pinkish and up to 1 cm wide. The color depends on what the penguin ate: white if it ate fish; pinkish if it ate krill. Penguin feces is semi-liquid goo whose viscosity is about that of olive oil. And the viscosity is the key to computing the pressure inside a penguin when it poops. Imagine loading a water pistol with ketchup, to make the ketchup project as fast and as far as water, you would need to pull the trigger much harder, because ketchup is so much more viscous. To calculate the pressure that a penguin produces when it poops, the two scientists came up with some approximations: First, they assumed that penguin feces are like water—low viscosity. They calculated the pressure that a penguin would need to fire water, and then adjusted the viscosity to that of olive oil and calculated how much more pressure a penguin would need to project that. Second, they assumed that a penguin's cloaca is horizontal while firing. Third, they assumed that the shot takes only about half a second, so that they could avoid having to know the shape of the penguin’s anus while firing. (If the excretion takes longer, the shape of the anus might change and that would influence the pressure the penguin need to excrete.) Under these approximations, the pressure required to shoot PENGUIN POO 40cm from a height of 20cm is around 34 mmHg. Further, if we take the viscosity into consideration, the pressure can be up to 77-450 mmHg, almost like the water pressure of an oral irrigator (60-500 mmHg). Although the pressure is still far too little to make penguins fly again, the encouraging news is that this research has raised a lot of feedback from other fields. A dinosaur expert wondered if the calculations could be applied in his research: can he track dinosaur nests by the fossils of feces or vice versa? Engineers for electric power lines in Africa expect the research can help them deal a power supply problem: power lines near vultures’ nests often short-circuit because of the vultures’ feces. Several zoo operators and bird-park rangers want to find out the "safe" distances for visitors to bird cages. However, as the paper said, the research neglects some facts: it did not count in the wind fact that might play an important role in how far the feces travel. Plus, the scientists intentionally ignore that the anus shape might change during the firing. To make up for these deficiencies, future researchers might need to observe in a hail of penguin poo. It will be an ordeal to see how much those poophysicists are willing to sacrifice for science. ------ 相關影片和原文報告 http://www.youtube.com/watch?v=qkz7tSbGDAM http://flow.arrr.net/penguins.pdf
 | 小松鼠 wrote: 哈，超有趣的題目啊 Nov. 13 |
| 我是董小茜wrote: 聽佩芳說妳快學成歸國了哦！！恭喜妳了～～ May 9 |
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