60秒科学:Maple Seed Flight Aerodynamics

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.

—Karen Hopkin

 

1 hummingbird   

n.蜂鸟

参考例句：

• The hummingbird perches on a twig of the hawthorn.小蜂鸟栖在山楂树枝上。
• The hummingbird is the only bird that can fly backward.蜂鸟是唯一能倒退向后飞的鸟。

2 moth   

n.蛾，蛀虫

参考例句：

• A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
• The sweater is moth-eaten.毛衣让蛀虫咬坏了。

3 maple   

n.槭树，枫树，槭木

参考例句：

• Maple sugar is made from the sap of maple trees.枫糖是由枫树的树液制成的。
• The maple leaves are tinge with autumn red.枫叶染上了秋天的红色。

4 maples   

槭树，枫树( maple的名词复数 )； 槭木

参考例句：

• There are many maples in the park. 公园里有好多枫树。
• The wind of the autumn colour the maples carmine . 秋风给枫林涂抹胭红。

5 germinate   

v.发芽；发生；发展

参考例句：

• Seeds will not germinate without water.没有水，种子是不会发芽的。
• Can thin and hollow seeds germinate?瘦瘪的种子能够发芽吗？

6 wafted   

v.吹送，飘送，（使）浮动( waft的过去式和过去分词 )

参考例句：

• The sound of their voices wafted across the lake. 他们的声音飘过湖面传到了另一边。
• A delicious smell of freshly baked bread wafted across the garden. 花园中飘过一股刚出炉面包的香味。 来自《简明英汉词典》

7 tornado   

n.飓风，龙卷风

参考例句：

• A tornado whirled into the town last week.龙卷风上周袭击了这座城市。
• The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。

8 hummingbirds   

n.蜂鸟( hummingbird的名词复数 )

参考例句：

• Hummingbirds have discovered that nectar and pollen are very nutritious. 蜂鸟发现花蜜和花粉是很有营养的。
• Why do hummingbirds and gorillas both have backbones? 为什么蜂鸟和大猩猩都有脊骨？

9 acorn   

n.橡实，橡子

参考例句：

• The oak is implicit in the acorn.橡树孕育于橡子之中。
• The tree grew from a small acorn.橡树从一粒小橡子生长而来。