SSS 2010-11-12
时间：2019-01-08 作者：英语课 分类：Scientific American(十一)月
This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.
If you've ever had to pick up and carry a tired child through the mall, you know that walking sometimes tuckers out the toddlers. Now scientists think they know why. The results appear in the Journal of Experimental Biology.
Larger animals tend to use less energy per gram of body mass than smaller ones do, even at rest. But what happens when they're in motion? Researchers recruited walkers of different ages and sizes, from a three-foot-tall kindergartner to a six-foot adult. While the subjects logged miles on the treadmill 1, the scientists measured their stride and metabolism 2.
And they found that people pretty much walk the same way, regardless of their stature 3. If you scaled a five-year-old up to be six-and-a-half feet tall, the giant child would lope along just like a similarly sized adult.
What's more, walkers of all heights use the same amount of energy per step. That means that big people don't conserve 4 energy by strolling in a more economical style. They expend 5 less energy because—just as you may have always suspected—they simply need fewer strides to cover the same ground. Which means that for some people a walk in the park ain't necessarily a walk in the park.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Karen Hopkin.
- The treadmill has a heart rate monitor.跑步机上有个脉搏监视器。
- Drugs remove man from the treadmill of routine.药物可以使人摆脱日常单调的工作带来的疲劳。
- After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
- All living matter undergoes a process of metabolism.生物都有新陈代谢。
- He is five feet five inches in stature.他身高5英尺5英寸。
- The dress models are tall of stature.时装模特儿的身材都较高。
- He writes on both sides of the sheet to conserve paper.他在纸张的两面都写字以节省用纸。
- Conserve your energy,you'll need it!保存你的精力，你会用得着的！