蜘蛛如何飛翔

Spiders can crawl17. But some spiders can fly， too！ When spiders fly， it is called ballooning（飛航）. How do they do it？ Scientists showed that they use electricity18 in the air.

You do not feel it， but electricity is in the air all around you. Rub19 a balloon on your hair，and the hair will point20 towards the balloon. This is because of static electricity（靜電）. Electricity can pull two things together. It can also push two things apart.

Before ballooning， spiders point their body up into the air. They send out a thin line of silk. The electricity in the air pulls on the silk. The electricity in the ground pushes the silk away. The spider lifts off into the sky！

蜘蛛能夠爬行，但有些蜘蛛還會(huì)飛！這種行為叫做“飛航”。它們是如何做到的？科學(xué)家們已證明，它們是從大氣電場(chǎng)中獲得了助力。

盡管無(wú)法察覺(jué)，我們四周的空氣實(shí)際上充斥著電荷。就像你對(duì)著頭發(fā)摩擦一個(gè)氣球，發(fā)絲便會(huì)被氣球吸引過(guò)去，這就是靜電的效果。靜電能夠使物體相互吸引或排斥。

“飛航”前的蜘蛛會(huì)將身體扳直，對(duì)著天空吐出一根極細(xì)的蛛絲。大氣中的正電荷會(huì)拉拽蛛絲，地表的負(fù)電荷會(huì)將蛛絲推開(kāi)，如此一來(lái)，蜘蛛便可乘電飛行！

Did you know？

Spiders may balloon to find a new home or to get away from other animals.

蜘蛛小知識(shí)

飛航是個(gè)非常有效的遠(yuǎn)距離遷徙方式。這種本領(lǐng)不僅能幫助蜘蛛躲避捕食者和競(jìng)爭(zhēng)對(duì)手的攻擊，還能將它們帶往資源豐富的新領(lǐng)地。