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Wow! Look at all that smoke.
哇！看看这些烟。
Yeah, that fiery tail is amazing.
是的，那发光的的尾巴太不可思议了。
Oh, hey there! Squeaks and I were just re-watching a video of the Atlas V rocket that took the Perseverance rover to Mars!
哦，嘿！我和吱吱刚刚又看了一遍阿特拉斯5号火箭的视频，它把“毅力”号探测器送上了火星！
A rover is a vehicle that's designed to explore another world.
探测器是用来探索另一个世界的交通工具。
And Perseverance is the 5th one to go to Mars!
“毅力”号探测器是第5个去火星的！
We've been thinking a lot about Perseverance and Mars in general ever since we watched the rover land on the planet earlier this year.
自从今年早些时候我们看到探测器在火星上着陆以来，我们一直在思考关于“毅力”号和火星的总体情况。
That was so exciting! But launches are exciting, too.
太令人兴奋了！但发射也令人兴奋。
The countdown, the burst of flame...and liftoff! I never ever get tired of watching them.
倒计时，火焰的爆发…和发射！我永远都看不腻。
And the rocket itself is so cool!
而且火箭本身也很酷！
I think they sort of look like pencils, mostly round on the bottom and pointy at the top.
我觉得它们有点像铅笔，底部大部分都是圆的，顶部是尖的。
Oh, that's a great question Squeaks!
问得好，吱吱！
Squeaks was wondering where in the rocket the rover was.
吱吱想知道探测器在火箭的什么地方。
It was towards the top, in a part called the spacecraft.
它在接近顶部的一个叫做航天器的地方。
So it was safely tucked away from all the fire and smoke that came out of the engines at the bottom of the rocket.
它被安全地藏了起来，远离火箭底部引擎冒出的火和烟。
It's sometimes hard to appreciate on a far away video, but rockets are huge.
从遥远的视频里有时很难看到，但火箭是巨大的。
And it's not surprising to hear that something that big weighs a lot!
那么大的东西很重是正常的。
It tipped the scale at more than 530,000 kilograms, that's like 100 elephants.
它的重量超过了53万公斤，相当于100头大象。
Oh, that's another great question, Squeaks!
吱吱，这也是一个好问题！
He wants to know, how does something so big and heavy get off the ground and all the way into space?
他想知道，这么大这么重的东西是如何离开地面，一路进入太空的？
Well, essentially, they push off. That's what all the fire and smoke is!
嗯，从本质上说，它们是被推出去的，就是那些火和烟！
Beneath the rocket is the launch pad.
火箭下面是发射台。
It's made of concrete, and is super strong.
发射台是由混凝土制成的，非常坚固。
When it's time for launch, the rocket engines mix and heat up two things called hydrogen and oxygen.
当发射的时候，火箭引擎将氢和氧这两种物质混合并加热。
They're both all around us in the air all the time, even though we can't see them.
我们身边时时刻刻都有氢和氧，只不过我们看不见。
Ooh, good thinking, Squeaks!
好主意，吱吱！
We do use oxygen in a special way ...we breathe it!
我们确实在以一种特殊的方式使用氧气……呼吸氧气！
But when oxygen and hydrogen mix together and they get really hot, they combine and form this really huge cloud that rushes out the end of the engine super fast...
但当氧气和氢气混合时，它们会变得非常热，会结合并形成巨大的云，以超级快的速度冲出引擎末端……
And it pushes against the launch pad...hard. Really hard.
它会非常用力地推着发射台。
Do you remember what we call something that pushes or pulls? A force.
你还记得我们把推或拉的东西叫做什么吗？力。
You're right. This huge push is a huge force.
没错，这个巨大的推力是一个巨大的力。
And what happens because of the force… or the effect of the force… is that the rocket lifts off the ground!
由于这个力的作用，火箭离开了地面！
Forces are all around us, and we see, and feel, their effects all of the time.
力就在我们身边，我们随时都能看到、感觉到它们的影响。
For example, a force called gravity keeps you...me… and everything around us on the ground.
例如，有一种叫做重力的力使你、我、一切东西待在地面上。
If gravity didn't exist, there'd be nothing to keep us on the ground.
如果没有重力，就没有什么东西能把我们留在地面上。
So even a tiny hop could send us off into space!
所以即使是一个小小的跳跃也能把我们送入太空！
So, thankfully, Earth's gravity is always pulling on us.
所以，谢天谢地，地球的引力一直在拉着我们。
Aw, that's fair enough.
啊，很公平。
We usually don't feel like we're being pulled on by the force of gravity, but that's just because we're used to it..
我们通常不会觉得自己被重力拉着，但那只是因为我们习惯了。
And there's a simple way to feel the force of gravity!
有一个简单的方法来感受重力！
All we have to do is jump.
我们要做的就是跳。
Ready?
准备好了吗？
When we jump, we make a force because we're pushing down on the ground with our feet. And that makes us go up!
当我们跳跃时，我们产生了一个力，因为我们用脚往下推地面，我们就会往上！
But… we didn't keep going up, did we?
但是，我们并没有一直往上，对吧？
That's because, once our feet left the ground, gravity took over and pulled us back to Earth.
那是因为，一旦我们的脚离开地面，重力就会接管并把我们拉回地球。
A rocket is basically the same idea as us jumping into the air… but on a much bigger scale.
火箭基本上和我们跳向空中的原理是一样的，但规模要大得多。
Ooo, yeah, good question!
哦，是的，问得好！
It did look like the rocket broke in mid-air, huh?
火箭好像是在半空中爆炸的，对吧？
Well, it turns out 100 elephants worth of rocket is actually too much to push all the way to Mars.
事实证明，100头大象那么大的火箭要一路推到火星实在是太大了。
So as the Atlas rocket moved away from the ground, it broke apart into a few big pieces called stages.
所以当阿特拉斯火箭离开地面时，它会分裂成几个大的碎片，称为“级”。
Each stage has its own engine and its own fuel.
每一级都有自己的发动机和燃料。
And when a stage uses up all its fuel, it drops its empty compartments to keep the rocket light and easy to fly.
当一个级用尽了所有的燃料，它就会放下空舱，以保持火箭的轻和易飞行。
Eventually all the stages fall away, leaving just the spacecraft!
最后，所有的级都脱落了，只剩下航天器！
The other thing you need to know is that the farther away the rocket gets from Earth, the weaker the pull of its gravity gets.
你需要知道的另一件事是，火箭离地球越远，它的引力就越弱。
So once the rocket gets the spacecraft far enough away, it can use much smaller engines to finish the trip!
因此，一旦火箭将航天器带到足够远的地方，它就可以使用更小的引擎来完成旅程！
Not all rocket engines work exactly this way.
并不是所有的火箭发动机都是这样工作的。
But they all make a force to help the rocket leave Earth and get into space.
但它们都产生了一种帮助火箭离开地球进入太空的力。
Let's find another rocket launch to watch, Squeaks, what do you say?
吱吱，咱们再去看一次火箭发射，你觉得怎么样？
Thanks for joining us! If you want to keep learning and having fun with me, Squeaks, Mister Brown, and all our other friends, be sure to hit the subscribe button, and we'll see you next time here at The Fort!
感谢您的收看！如果你想继续学习，和我、吱吱、布朗先生以及我们所有的朋友一起快乐，一定要点击订阅按钮，咱们下次城堡见！
