With thunder， there's always lots to hear. Now there's also something to see. For the first time， scientists have precisely mapped the loud clap radiating from a lightning strike. This picture of thunder's origins could reveal the energies involved in powering some of nature's flashiest light shows.

Lightning strikes when an electric current flows from a negatively charged cloud to the ground. This rapidly heats and expands the surrounding air， creating sonic shock waves. We hear this as thunder.

Scientists have a basic understanding of the origins of thunder. Still， experts have lacked a detailed picture of the physics powering the loud cracks and low rumbles.

Maher Dayeh works at the Southwest Research Institute in San Antonio， Texas. As a heliophysicist， he studies the sun and its effects on the solar system， including Earth. He and his colleagues also study lightning — by making their own. These experts trigger the bolts by firing a small rocket into an electrically charged cloud. Trailing behind the rocket is a long， Kevlar-coated copper wire. The lightning travels along that wire to the ground.

For their new experiment， the scientists used 15 sensitive microphones laid out 95 meters （312 feet） from the strike zone. The team then precisely recorded the incoming sound waves. Those from higher elevations took longer to reach the microphones.

That allowed the scientists to map the acoustic （sound） signature of the lightning strike. That map revealed the strike with "surprising detail".

How loud a thunderclap sounds will depend on the peak electric current flowing through the lightning， the researchers found. Explains Dayeh， this discovery could one day allow scientists to use thunder to sound out the amount of energy powering a lightning strike.

用眼睛“看”雷聲

雷聲轟鳴，不絕于耳。但現(xiàn)在雷聲也可用“眼”觀?？茖W(xué)家初次用圖精確地繪制出雷擊所發(fā)出的巨大霹靂聲。該雷聲起源圖能夠揭示自然界最耀眼的閃光背后的驅(qū)動(dòng)力量。

當(dāng)電流從帶負(fù)電荷的云團(tuán)流向地面的時(shí)候，雷擊就發(fā)生了。雷擊使周?chē)諝鉁囟妊杆偕卟⑴蛎?，產(chǎn)生沖擊聲波，沖擊聲波就是我們聽(tīng)到的雷聲。

科學(xué)家們已經(jīng)基本理解了雷聲的起源。但他們還是缺乏一張能夠詳細(xì)描寫(xiě)產(chǎn)生這種巨大霹靂聲和低沉轟鳴聲的物理學(xué)動(dòng)因的圖。

Maher Dayeh就職于美國(guó)得克薩斯州圣安東尼奧市的西南研究所。作為一名太陽(yáng)物理學(xué)家，他從事研究太陽(yáng)以及太陽(yáng)對(duì)太陽(yáng)系的影響，包括對(duì)地球的影響。他和同事們也研究閃電，他們通過(guò)自己創(chuàng)造的閃電來(lái)一探閃電的究竟。這些專家將一枚小型火箭發(fā)射到負(fù)電荷云團(tuán)來(lái)觸發(fā)雷電，火箭的尾部系著一根長(zhǎng)長(zhǎng)的、用凱夫拉爾纖維進(jìn)行過(guò)表面處理的銅線。閃電通過(guò)那根銅線傳導(dǎo)到地面。

在一項(xiàng)新的實(shí)驗(yàn)中，科學(xué)家將15個(gè)高靈敏度的擴(kuò)音器安置在離雷擊區(qū)95米（312英尺）以外的地方。然后他們精確地記錄了傳導(dǎo)進(jìn)來(lái)的聲波。聲波傳導(dǎo)到擴(kuò)音器的時(shí)間隨著聲波源高度的增加而增加。

這樣，科學(xué)家就能繪制出雷擊的聲波標(biāo)記圖。這張圖揭示的雷擊的精細(xì)程度令人驚訝。

這些研究者發(fā)現(xiàn)，霹靂的響亮程度取決于穿越閃電的峰值電流。Dayeh解釋道，這一發(fā)現(xiàn)有朝一日能夠使科學(xué)家運(yùn)用雷鳴來(lái)搞清楚驅(qū)動(dòng)雷擊所需能量的大小。

（注意斜體字的譯法）

Robots to Attend School in Australia

For the first time in Australia， research is being conducted into how robots can be effectively implemented into primary and secondary school curriculums to improve classroom （1） l .

The three year research （A） p ， led by Swinburne University of Technology， will see two South Australian schools per term trial the use of NAO robots – humanoid robots developed by Aldebaran Robotics， a French robotics company.

Teachers will complete regular online surveys about the way the robots are being used to educate the （B） s and encourage class engagement. They will also be asked about the challenges of using robots in the （2） c .

"Robots are becoming a part of （3） s . It is the responsibility of Australian schools to prepare their students with the skills needed for the future." said lead researcher， Swinburne's Dr Therese Keane.

While robots have occasionally been used in schools， there is currently no （C） e or findings that suggest how robots can assist both teachers and students.

"Through the three year research programs， we hope to identify the 'best practice' way that （4）

r can be implemented into school curriculums. We want the robots to improve classroom learning， not simply be a novelty or distraction." Keane said.

Introducing robots into the school curriculum will also give the students first-hand access to coding and programming.

"One of the key （D） f of the NAO robots is that they can be programmed to talk， dance and move around by the students using software on the （E） c ." Keane said.

"Coding has been identified as a necessary skill for the next-generation of workers. These robots give the students an accessible and fun way to practice and improve their （F） c skills." Keane said.

（A， B， C， D， E， F FOR CROSS， 1， 2， 3， 4 FOR DOWN. The first letters of the absents were given.）