英语 英语 日语 日语 韩语 韩语 法语 法语 德语 德语 西班牙语 西班牙语 意大利语 意大利语 阿拉伯语 阿拉伯语 葡萄牙语 葡萄牙语 越南语 越南语 俄语 俄语 芬兰语 芬兰语 泰语 泰语 泰语 丹麦语 泰语 对外汉语

美国科学60秒 SSS 2012-10-12

时间:2013-06-19 08:26来源:互联网 提供网友:gmeng   字体: [ ]
特别声明:本栏目内容均从网络收集或者网友提供,供仅参考试用,我们无法保证内容完整和正确。如果资料损害了您的权益,请与站长联系,我们将及时删除并致以歉意。
    (单词翻译:双击或拖选)

 Hair helps keep you warm, right? But hair can also keep you cooler than bare skin, as long as the hair is not too thick. So says a study in the journal PLoS ONE.

 
Researchers studied elephants, which have very thin coats of hair. It's easy for the beasts to overheat: they may face temperatures of up to 120 degrees Fahrenheit1, and they don't have much skin surface area to radiate the heat relative to their big body volume. 
 
That's where the hair comes in. The researchers wrote equations modeling the elephants' hairy skin. As they expected, thick hair traps air and keeps the body warm. But below a certain density2, hair stops insulating and wicks heat off the body instead—helping the elephants get rid of an extra 20 percent of their body heat, especially on windless days.
 
Heat sinks inside computers work in a similar way, with pins sticking up to help dissipate the interior heat.
 
The researchers speculate that hair may have actually evolved to help animals stay cool, because it first sprouted3 in mammals over a hundred million years ago in a hot climate. Hair-raising times, indeed.

点击收听单词发音收听单词发音  

1 Fahrenheit hlhx9     
n./adj.华氏温度;华氏温度计(的)
参考例句:
  • He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
  • The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。
2 density rOdzZ     
n.密集,密度,浓度
参考例句:
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
3 sprouted 6e3d9efcbfe061af8882b5b12fd52864     
v.发芽( sprout的过去式和过去分词 );抽芽;出现;(使)涌现出
参考例句:
  • We can't use these potatoes; they've all sprouted. 这些土豆儿不能吃了,都出芽了。 来自《简明英汉词典》
  • The rice seeds have sprouted. 稻种已经出芽了。 来自《现代汉英综合大词典》
本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎点击提交分享给大家。
------分隔线----------------------------
TAG标签:   美国60秒科学  SSS  英语听力
顶一下
(0)
0%
踩一下
(0)
0%
最新评论 查看所有评论
发表评论 查看所有评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:
听力搜索
推荐频道
论坛新贴