rú如guǒ果nǐ你bǎ把yī一méi枚fēi飞xiàng向tài太kōng空de的huǒ火jiàn箭zuò做chéng成yī一gè个wán完zhěng整、bù不chāi拆fēn分de的dà大tiě铁guàn罐zi子，lǐ里miàn面zhuāng装mǎn满chén沉diān甸diān甸de的rán燃liào料，xiǎo小xióng熊māo猫gào告sù诉nǐ你：zhè这méi枚huǒ火jiàn箭huì会yīn因wèi为zì自shēn身shí实zài在shì是tài太zhòng重tài太bèn笨，gēn根běn本fēi飞bù不le了duō多yuǎn远。cōng聪míng明de的háng航tiān天kē科xué学jiā家xiǎng想chū出le了yī一gè个jué绝miào妙de的jué绝zhāo招，jiào叫zuò做“duō多jí级huǒ火jiàn箭”！tā他men们bǎ把huǒ火jiàn箭de的shēn身tǐ体xiàng像dié叠jī积mù木yī一yàng样fēn分chéng成hǎo好jǐ几jié节：zuì最xià下miàn面de的dì第yī一jí级huǒ火jiàn箭shǒu首xiān先diǎn点huǒ火，pēn喷chū出dà大huǒ火qiú球pīn拼mìng命wǎng往shàng上fēi飞；děng等zhè这yī一jié节de的rán燃liào料quán全bù部shāo烧wán完hòu后，tā它jiù就huì会zhǔ主dòng动wán完chéng成rèn任wù务，“pā啪dā嗒”yī一shēng声cóng从shēn身tǐ体shàng上tuō脱luò落diào掉xià下lái来。jǐn紧jiē接zhe着，shàng上miàn面de的dì第èr二jí级huǒ火jiàn箭lì立kè刻jiē接lì力diǎn点huǒ火，tuī推zhe着yǐ已jīng经biàn变qīng轻hěn很duō多de的shēn身tǐ体jì继xù续fēng疯kuáng狂jiā加sù速。dà大míng名dǐng鼎dǐng鼎de的ā阿bō波luó罗dēng登yuè月huǒ火jiàn箭jiù就yǒu有zú足zú足sān三jí级nà那me么gāo高ne呢！huǒ火jiàn箭fēn分jí级fēn分lí离de的shí时hòu候，tiān天kōng空zhōng中hái还huì会liú留xià下yī一dào道dào道xiàng像xiān仙nǚ女sī丝dài带yī一yàng样měi美lì丽de的guǐ轨jì迹yún云ne呢！

If you built a spacebound rocket as a single, solid metal tank packed with heavy fuel, Little Panda tells you: this rocket would be too heavy and clumsy to fly very far. Smart aerospace scientists came up with a brilliant strategy called 'staging rockets'! They divide the rocket's body into several sections, stacked just like building blocks. The bottom first stage ignites first, blasting giant fireballs to soar upward. Once its fuel is completely burned up, it fulfills its duty and detaches with a 'snap.' Right away, the second stage above takes over and ignites, pushing the now much lighter body to accelerate like crazy. The famous Apollo moon rocket was a whopping three stages tall! When the rocket stages separate, they leave behind gorgeous vapor trails in the sky that look like fairy ribbons!

👧 Compare With You

你抬头看天空的方式，和今天学的太空知识有什么联系？ How does looking at the sky connect to today's space fact?

📚 Vocabulary

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🎯 Fun Challenge

如果把火箭做成一个完整、不拆分的大铁罐子，会发生什么？

What happens if a rocket is made as one solid, un-separated big metal can?

💡 想一想刚才读到的内容。 Think about what you just read.