84 Spaceship Motions and Deep, Deep Oceans-High

Spaceship Motions and Deep, Deep Oceans FOCUS Question How do machines help people explore outer space and the deepest oceans?

宇宙飞船运动和深海焦点问题机器如何帮助人们探索外层空间和最深的海洋?

Extreme Travelers Think about traveling to the bottom of an ocean. It is dark and cold. The water above you is very heavy. The pressure is more than 1,000 times greater than on land. Now think about traveling into space. It takes a lot of fuel to escape the pull of Earth's gravity. Then, once you are there, you have to deal with feeling weightless. We have designed machines that can go to these extreme places. We have explored our solar system and the deep ocean. Which machines do we use? What makes them work?

想象一下去海底旅行。 又黑又冷。你上面的水很沉。 压力是陆地上的1000多倍。 现在想想太空旅行。 它需要大量的燃料来摆脱地球的引力。 然后，一旦你到了那里，你必须处理失重的感觉。 我们设计的机器可以去这些极端的地方。 我们已经探索了太阳系和深海。 我们用哪些机器?是什么让它们起作用?

Fighting Gravity Blow up a balloon and let it go. What happens? It flies! The balloon pushes away air. The air pushes the balloon in the opposite direction. This is similar to how a rocket engine works. When you blow up and release a balloon, it goes only a short distance. Rockets go all the way to outer space! This takes a lot of fuel. When rocket fuel burns, some of its energy changes into heat, light, and sound. The rest changes into motion. Gases rush from the bottom of the rocket, toward the ground. The rocket flies in the opposite direction, up into the sky. This force is called thrust. The upward thrust must be stronger than the downward pull of gravity for the rocket to fly.

吹起一个气球，然后让它飞走。 会发生什么呢?这苍蝇!气球把空气推开。 空气将气球推向相反的方向。 这与火箭发动机的工作原理类似。 当你吹气并释放一个气球时，它只能飞很短的距离。 火箭可以飞到外太空!这需要大量的燃料。 当火箭燃料燃烧时，它的一些能量转化为热、光和声音。 剩下的部分变成了运动。 气体从火箭底部冲向地面。 火箭飞向相反的方向，飞向天空。 这种力叫做推力。 火箭要飞起来，向上的推力必须大于向下的引力。

Rockets and Shuttles Between 1969 and 1972, people went to the Moon! They flew in Saturn rockets. These rockets had three parts, called stages. The bottom stage was the biggest and produced the most thrust. It pushed the rocket up very high and then dropped away when it ran out of fuel. The second stage pushed the rocket higher. The third stage carried the spacecraft and people the rest of the way to the Moon. Later, engineers designed spaceships that were shaped more like airplanes. They could be used more than once. These were called space shuttles.

1969年到1972年间，人类登上了月球!他们乘坐土星火箭飞行。 这些火箭有三个部分，称为级。 底级最大，推力最大。 它把火箭推到很高的地方，然后在燃料耗尽时下落。 第二级将火箭推得更高。 第三级运载着宇宙飞船和宇航员到达月球。 后来，工程师们设计了形状更像飞机的宇宙飞船。 它们可以使用不止一次。 这些被称为航天飞机。

Over the years, people have made rockets that go higher and higher. V-2 Rocket The V-2 rocket was the first rocket to go into space. It was only 14 meters (45 ft.) tall, but it had a lot of thrust. Saturn V Rockets Saturn V rockets were the tallest and heaviest rockets ever built. They were 110 meters (363 ft.) tall. Space Shuttles Only six space shuttles were made. They were used to transport humans and tools into space and back. Scientists conducted experiments on the space shuttles. Wowser! Space shuttles orbited Earth quickly. The astronauts on board saw a sunrise or sunset every 45 minutes!

多年来，人们制造的火箭飞得越来越高。 V-2火箭V-2火箭是第一枚进入太空的火箭。 它只有14米(45英尺)高，但推力很大。 土星5号火箭是有史以来最高、最重的火箭。 他们有110米(363英尺)高。 航天飞机只制造了6架。 它们被用来运送人和工具进入太空并返回。 科学家们在航天飞机上进行实验。 老古板!航天飞机绕地球快速飞行。 宇航员每45分钟就能看到一次日出或日落!

Fighting Buoyancy Submarines have the opposite problem of rockets. They need to go down instead of up! While rockets fight gravity, submarines must work against buoyancy (BOY-un-see). Buoyancy is the upward push of a liquid or gas. It is what makes things float in water— or on air. To submerge, or go underwater, submarines must overcome buoyancy. They do this by becoming denser. Density is the amount of material in a certain space. Think of a piece of cork and a solid rock that are the same size. The rock has more material in it. The rock is denser than the cork. A cork floats in water, while most rocks sink. Think About It Which is denser: this rubber ball or the bowling ball? Why? How could you test your answer?

战斗浮力潜艇的火箭问题正好相反。 他们应该往下走，而不是向上!当火箭对抗重力时，潜艇必须对抗浮力。 浮力是液体或气体向上的推力。 它使物体漂浮在水中或空气中。 为了潜入水中，潜艇必须克服浮力。 它们的密度越来越大。 密度是指一定空间内物质的数量。 想象一块软木塞和一块相同大小的坚固岩石。 岩石里有更多的物质。 岩石的密度比软木塞大。 软木在水中漂浮，而大多数岩石会下沉。 想想哪个密度大:橡胶球还是保龄球? 为什么?你如何检验你的答案呢?