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(单词翻译:双击或拖选)
This is Scientific American's 60-second Science. I'm Karen Hopkin. This will just take a minute.
What do a hummingbird1, a moth2, and a maple3 tree have in common? They all use a similar trick to fly. Okay, okay, a maple tree doesn’t fly. But its seeds kind of do. Maples4 make those little whirlybird seeds you see spiraling down in droves each spring. Their papery little wings keep them aloft so they can find a good place to germinate5 and make a new maple. But how they manage to fall so slowly has been a bit of a mystery—until now.
Scientists filmed maple seeds as they wafted6 through a smoke-filled wind tunnel. And they found that a spiral of air develops on top of each falling seed’s wing. That vortex generates lift, and acts like a miniature tornado7 that sucks the seed up. The study appears in the June 12th issue of the journal Science.
The same type of vortex also helps bats, hummingbirds8 and insects soar. So it seems that plants and animals have both stumbled on the same aerodynamic approach to battling gravity. Which explains why the acorn9 might not fall far from the tree, but maple seeds can really go the distance.
Thanks for the minute for Scientific American's 60-second Science. I'm Karen Hopkin.
1 hummingbird | |
n.蜂鸟 | |
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2 moth | |
n.蛾,蛀虫 | |
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3 maple | |
n.槭树,枫树,槭木 | |
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4 maples | |
槭树,枫树( maple的名词复数 ); 槭木 | |
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5 germinate | |
v.发芽;发生;发展 | |
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6 wafted | |
v.吹送,飘送,(使)浮动( waft的过去式和过去分词 ) | |
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7 tornado | |
n.飓风,龙卷风 | |
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8 hummingbirds | |
n.蜂鸟( hummingbird的名词复数 ) | |
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9 acorn | |
n.橡实,橡子 | |
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