60秒科学:Maple Seed Flight Aerodynamics
What do a hummingbird 1, a moth 2, and a maple 3 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. Maples 4 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 germinate 5 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 wafted 6 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 tornado 7 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, hummingbirds 8 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 acorn 9 might not fall far from the tree, but maple seeds can really go the distance.
—Karen Hopkin
- 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。
- 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。
- 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。
- 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。
- 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？
- 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》
- 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。
- 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？