72 Perpetual Motion: Fact or Fiction?-High

Perpetual Motion: Fact or Fiction FOCUS? Question Is perpetual motion possible?

永动机:事实焦点还是虚构焦点? 永动机可能吗?

A Machine That Never Stops Have you ever used a gyroscope? It is like a top. You pull a string, and then it spins for a very long time. Is it possible to make a gyroscope spin so fast that it never stops? If so, it would be in perpetual (per-PEH-chew-uhl) motion. A perpetual motion machine is a device that moves forever, without adding energy. But can such a machine exist? The blades of a wind turbine may seem to be in constant motion, but the turbine is not a perpetual motion machine. Wind is made of air particles that have kinetic energy, the energy of motion. When the moving air blows against the turbine blades, some of the energy moves the blades. If the wind stopped, so would the turbine.

你用过陀螺仪吗? 它就像一个陀螺。你拉一根绳子，它就会旋转很长时间。 有没有可能让陀螺仪旋转得如此之快以至于永不停止? 如果是这样的话，它将处于永恒的运动状态。 永动机是一种永远运动而不增加能量的装置。 但是这样的机器真的存在吗? 风力涡轮机的叶片似乎在不断地运动，但涡轮机并不是永动机。 风是由具有动能的空气粒子构成的，动能就是运动的能量。 当流动的空气吹向涡轮叶片时，一些能量使叶片移动。 如果风停止了，涡轮机也会停止。

Why would we want a perpetual motion machine? We need large amounts of energy to run our phones, cars, and other machines. To produce energy, we burn fossil fuels such as coal, oil, and natural gas. We also use wind farms, dams, and nuclear power plants. These energy sources often create pollution or disrupt environments and ecosystems. If we could invent a perpetual motion machine, it would keep moving without adding energy. In fact, its motion could be used to produce more energy. Just imagine... free, clean energy!

我们为什么要永动机? 我们需要大量的能量来运行我们的手机、汽车和其他机器。 为了生产能源，我们燃烧煤、石油和天然气等化石燃料。 我们还使用风力发电场、水坝和核电站。 这些能源经常造成污染或破坏环境和生态系统。 如果我们能发明永动机，它就能在不增加能量的情况下继续运动。 事实上，它的运动可以用来产生更多的能量。 想象一下…免费的清洁能源!

An Object in Motion... Unfortunately, no one has ever successfully designed a perpetual motion machine. Newton's first law of motion says that an object in motion will stay in motion unless it is acted on by outside forces. This seems to mean that perpetual motion should be possible. In the real world, however, outside forces always interfere. When a baseball is hit into the air, the forces of air resistance and gravity act on it. Air resistance is a kind of friction that slows objects moving through air. Gravity pulls the ball down to the ground.

运动中的物体……不幸的是，从来没有人成功地设计出永动机。 牛顿第一运动定律说，运动中的物体将保持运动状态，除非它受到外力的作用。 这似乎意味着永动机是可能的。 然而，在现实世界中，外部力量总是会干涉。 当棒球被打到空中时，空气阻力和重力作用在棒球上。 空气阻力是一种摩擦，使物体在空气中移动的速度变慢。 重力把球拉到地面。

Gravity Machines Gravity is the force that attracts objects toward each other and toward Earth's center. Because this force is always present on Earth, people have tried to make perpetual motion machines using gravity. In the machine on this page, gravity pulls the lifted ball downward. It collides with the other balls, and the last ball flies upward, until it is pulled down again by gravity. Does this machine convert gravity into perpetual motion? It may seem like it, but no. As kinetic energy travels from one ball to the next, friction slows the movement slightly. The energy from the initial human pull to get the machine moving will eventually run out because of friction.

重力机器重力是将物体吸引到彼此和地球中心的力。 由于这种力在地球上一直存在，人们试图利用重力制造永动机。 在本页的机器中，重力将被举起的球向下拉。 它与其他球碰撞，最后一个球向上飞，直到它再次被重力拉下来。 这台机器能把重力转换成永动机吗? 看起来是这样，但事实并非如此。 当动能从一个球传递到下一个球时，摩擦力会使运动略微减慢。 最初人类推动机器移动的能量最终会因为摩擦而耗尽。

Frictional Forces Friction is a force caused by two objects rubbing together. Friction changes kinetic (moving) energy to thermal energy, or heat. Think about rubbing your hands together very quickly. As you use kinetic energy to move your hands against each other, they get warm. The warmth is thermal energy caused by friction. In every machine, friction eventually "steals" enough kinetic energy to make the machine stop. Friction changes some of the energy of motion into heat energy. Then the heat energy is transferred into the air or nearby objects. If the design is very good, there will be very little friction, but no machine runs forever without needing more energy.

摩擦力是两个物体相互摩擦产生的力。 摩擦将动能转化为热能，即热量。 想象一下快速地搓你的手。 当你用动能让你的手相互摩擦时，它们就会变暖。 热量是摩擦产生的热能。 在每台机器中，摩擦最终都会“窃取”足够的动能，使机器停止运转。 摩擦把一些运动能量转化为热能。 然后热能被传递到空气或附近的物体中。 如果设计得非常好，摩擦就会非常小，但没有一台机器永远运行而不需要更多的能量。