荷花塘小区:第一章磁性—建造一座高斯步枪磁直线加速器

This very simple toy uses a magnetic chain reaction to launch a steel marble at a target at high speed. 这很简单的玩具使用一个磁性的连锁反应发射一钢大理石目标在高速度。The toy is very simple to build, going together in minutes, and is very simple to understand and explain, and yet fascinating to watch and to use.玩具是很简单的建设,在一起了在分钟,很容易理解和解释,并且却又令人观察和使用。

Click on image for animated view点击图像动画的观点

The photo above shows six frames of video showing the gauss rifle in action. 上述照片显示六个帧的视频显示高斯步枪的实际行动。Each frame shows 1/30th of a second. 每个框显示1/30th一秒。In the first frame, a steel ball starts rolling towards a magnet taped to a wooden ruler. 在第一个框架、一个钢球滚动开始对磁铁贴在一个木制的统治者。In the second frame, a second ball can be seen speeding between the rightmost two magnets. 在第二个框架、一个第二个球可以看到之间的两块磁铁rightmost超速行驶。By the third frame, the accelerator has sped up so much that the ball that is seen leaving the left side of the device is just a blur as it smashes into the target. 在第三架、加速器有加快那么看见离开球装置的左边只是一种模糊,因为它攻击到目标。One ball, starting at rest, has caused another ball to leave the device at a very high speed.一个球,开始在休息,引起了另外的一个球离开装置在非常高的速度。

Click on image for larger view点击图像对较大的观点

The materials are simple. 这些材料是简单的。We need a wooden ruler that has a groove in the top in which a steel ball can roll easily. 我们需要一个木制的统治者,世界顶尖的槽内,一个钢球能滚动很容易。Any piece of wood or aluminum or brass with a groove will work. 任何一块木头或是铝或铜管与凹槽行不通。We chose the ruler because they are easy to find around the house or at school or at a local stationery store.统治者,我们的选择,因为它们容易找到在家里还是在学校或在当地一家文具店。

We need some sticky tape. 我们需要一些的粘性胶带。Again, almost any kind will do. 再次,几乎任何类型就行了。Here we use Scotch brand transparent tape, but vinyl electrical tape works just as well.在这里我们用威士忌品牌透明胶带,但乙烯基电工胶带运行就。

We need four magnets. 我们需要四个磁体。Most any type will do, but the stronger the magnets are, the faster the balls will go. 多数任意类型将做,但是越强,越快磁体的球去。Here we use the super strong gold-plated neodymium-iron-boron magnets we have made available in our在这里我们用超级强大的镀金neodymium-iron-boron磁铁我们已经取得了可在我们的健康有好处catalog目录for the other projects. 对于其他的项目。They work great.他们很有用。

We will also need nine steel balls, with a diameter that is a close match to the height of the magnets. 我们也将需要九钢球,直径是一场势均力敌的比赛的磁体的高度。We use 5/8 inch diameter nickel plated steel balls from our我们用5 / 8英寸直径的镀镍钢球从我们的catalog目录.

The only tool we will need is a sharp knife for trimming the tape.唯一的工具,我们需要是一把锋利的小刀削减录音。

Click on image for larger view点击图像对较大的观点

We start by taping the first magnet to the ruler at the 2.5 inch mark. 我们先拍的第一块磁铁统治者在2.5”的标志。The distance is somewhat arbitrary -- we wanted to get all four magnets on a one foot ruler. 距离是某些武断的——我们想要在一个磁铁四脚的统治者。Feel free to experiment with the spacing later.随时实验在间隔之后。

Click on image for larger view点击图像对较大的观点

With the sharp knife, trim off any excess tape. 用锋利的刀,修剪掉多余的带子。Be careful, since the knife will be strongly attracted to the magnet.小心,因为刀会受到强烈吸引到磁铁。

It is very important that you keep the magnets from jumping together. 很重要的是要保持从跳的磁体在一起。They are made of a brittle sintered material that shatters like a ceramic. 它们是用一种易碎的烧结材料,粉碎了像陶瓷。Tape the ruler to the table temporarily, so that it doesn't jump up to the next magnet as you tape the second magnet to the ruler.用胶布把统治者临时表,这样就不会跳接下来的永磁起你带第二磁铁给以色列中的王。

Click on image for larger view点击图像对较大的观点

Continue taping the magnets to the ruler, leaving 2.5 inches between the magnets.继续拍的磁铁给以色列中的王,留下的2.5英寸之间的磁体。

When all four magnets are taped to the ruler, it is time to load the gauss rifle with the balls.当所有的四个磁体贴在统治者,它是时间载入高斯步枪的球。

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To the right of each magnet, place two steel balls. 右边的每个磁铁、放置两钢球。Arrange a target to the right of the device, so the ball does not roll down the street and get lost.安排一个目标,以正确的设备,所以球没有卷街上迷路。

To fire the gauss rifle, set a steel ball in the groove to the left of the leftmost magnet. 点燃这些高斯步枪,设定一个钢球将处于最佳状态的左边最左边的那个磁铁。Let the ball go. 让球去。If it is close enough to the magnet, it will start rolling by itself, and hit the magnet.如果它是足够接近磁铁,它便会开始滚动,自行击中了磁铁。

Click on image for larger view点击图像对较大的观点

When the gauss rifle fires, it will happen too fast to see. 当高斯步枪火灾,这将发生太快要看的东西。The ball on the right will shoot away from the gun, and hit the target with considerable force. 球在右边要射离开枪,命中目标相当大的力量。Our one foot long version is designed so the speed is not enough to hurt someone, and you can use your hand or foot as a target.我们有一个英尺长的版本是设计是不够的速度伤害某人时,你可以用你的手、脚作为目标。

How does it do that?它如何做呢?

When you release the first ball, it is attracted to the first magnet. 当你释放出第一个球,这是吸引到第一个磁铁。It hits the magnet with a respectable amount of force, and a kinetic energy we will call "1 unit".它击中磁铁所施加的力,有一份体面的动能,我们会叫“1单位”。

The kinetic energy of the ball is transfered to the magnet, and then to the ball that is touching it on the right, and then to the ball that is touching that one. 动能转换球的那块磁铁,再到球体,它摸它在右边,再到球碰到那一个。This transfer of kinetic energy is familiar to billiards players -- when the cue ball hits another ball, the cue ball stops and the other ball speeds off.这桩转会高空动能是熟悉的球员的时候,台球母球撞到了另球,直击主球球心站和其他球的速度了。

The third ball is now moving with a kinetic energy of 1 unit. 第三球现在正与动能1股。But it is moving towards the second magnet. 但它正在向第二磁铁。It picks up speed as the second magnet pulls it closer. 它捡起速度为第二磁铁吸引它更近。When it hits the second magnet, it is moving nearly twice as fast as the first ball.当它击中第二磁铁、移动近两倍,第一个球。

The third ball hits the magnet, and the fifth ball starts to move with a kinetic energy of 2 units. 第三弹打磁铁,和第五届球开始移动,2个单元动能。It speeds up as it nears the third magnet, and hits with of 3 units of kinetic energy. 它加快速度,因为它靠近第三磁铁,支安打、3单位的动能。This causes the seventh ball to speed off towards the last magnet. 这导致7球,加速离开向最后的磁铁。As it gets drawn to the last magnet, it speeds up to 4 units of kinetic energy.当我逐渐磁铁吸引到最后时,它就加速到4单位的动能。

The kinetic energy is now transfered to the last ball, which speeds off at 4 units, to hit the target.现在动能转换过去的球,它的速度从4个单位,射中目标。

Another way of looking at the mechanism另一种方式的看着机制

When the device is all set up and ready to be triggered, we can see that there are four balls that are touching their magnets. 在设备被设置好准备被触发的,我们可以看到这儿有四个球,触摸他们的磁体。These balls are at what physicists call the "ground state". 这些球都是在什么物理学家所谓的“地面的国家”。It takes energy to move them away from the magnets.它需要能量运转他们离开的磁铁。

But each of these balls has another ball touching it. 但是这每个球有另一个球触摸它。These second balls are not at the ground state. 这些第二落点的地面也不在状态。They are each 5/8ths of an inch from a magnet. 他们每个人的5/8ths一英寸一块磁铁。They are easier to move than the balls that are touching the magnet.更易移动的触球的不同的磁铁。

If we were to take a ball that was touching a magnet, and pull it away from the magnet until it was 5/8ths of an inch away, we would be adding energy to the ball. 假如我们以一个球体,是令人感动的一块磁铁、和拉它离磁铁,直到它5/8ths英寸走了后,我们将会增加能量去舞会的事。The ball would be pulling towards the magnet with some considerable force. 球将会对磁铁与相当大的力量。We could get the energy back by letting the ball go.我们可以得到能量回让球去。

After the gauss rifle has fired, the situation is different. 高斯后步枪发射了,情况就完全不同了。Now each of the balls is touching a magnet. 现在每一个球是动人的一块磁铁。There is one ball on each side of each magnet. 有一个球的每一边每个磁铁。Each ball is in its ground state, and has given up the energy that was stored by being 5/8ths of an inch from a magnet. 每个球在其地面状态,已放弃储存的能量被5/8ths一英寸的一块磁铁。That energy has gone into the last ball, which uses it to destroy the target.能源已进入最后一个球,利用它来毁掉目标。

Speed and kinetic energy速度和动能

The kinetic energy of an object is defined as half its mass times the square of its velocity. 一个物体的动能一半的定义是质量乘以广场的速度。As each magnet pulls on a ball, it adds kinetic energy to the ball linearly.当每个磁铁吸引在球上,球的动能线性的。

But the speed does not add up linearly. 但快速并不把线性的。If we have 4 magnets, the kinetic energy is 4, but the speed goes up as the square root of the kinetic energy. 如果我们有4磁石的著磁,动能4,运行速度的上升的平方根动能。As we add more magnets, the speed goes up by a smaller amount each time. 当我们添加更多的磁石的著磁,速度上升,少得多,每次。But the distance the ball will roll, and the damage it causes to what it hits, is a function of the kinetic energy, and thus a function of how many magnets we use.但距离的球将书卷,所造成的危害后果给它支安打,是一个函数的动能,因此多少磁铁的功能,我们使用。

We can keep scaling up the gun until the kinetic energy gets so high that the last magnet is shattered by the impact. 我们可以把同比增长的枪,直到动能变得这么高,最后磁铁都被摧毁的影响。After that, adding more magnets will not do much good.在那之后,增加更多的磁铁将不做多好啊。

Why a circular track will not be a perpetual motion device为什么一个圆形的铁路将不是一个永恒的运动设备

I have been getting a lot of mail asking what would happen if we made the track circular. 我已经有很多邮件问什么是要知道如果我们做出了轨道圆。Would we get free energy? 我们能获得免费的能量的呢?Would the balls keep accelerating forever?将球保持加速到永远吗?

I have been tempted to reply with the famous quote: "There are two kinds of people in the world -- those who understand the second law of thermodynamics, and those who don't".我一直想回复,与著名的引用到:“有两种世界上的人——那些懂得热力学第二定律,另一种则不懂”。

However, I am not the kind of person to leave an inquiring mind unsatisfied, and it is more productive (and kind) to explain in a little more depth what is going on.然而,我不是那种离开的人追根究底的精神不满,而且更产量和亲切的)解释在一个多深度是怎么回事。

Suppose you made a circular track, and put two balls after each magnet. 假设你犯了一个循环的轨道上,而把两球之后,每个磁铁。When the last ball is released, it encounters a magnet that has two balls at the ground state. 当最后一个球被发布,它遇到一个一块磁铁,有两个球于地面的状态。There is no energy to be had from this magnet. 没有能从这磁铁。The ball just bounces back.球正好能重新振作起来。

Now suppose you had placed three balls after each magnet. 现在,假设你有放三球之后,每个磁铁。When the last ball is released, it hits a ball that is 5/8ths inch from the magnet. 当最后一个球是释放,它击中一个球体,它5/8ths英寸磁铁。It has not gained much momentum, because most of the momentum gained is in the last half inch as the magnet pulls much stronger on things that are closer. 它没有赢得了动量,由于多数的动力源自处在最后半英寸的磁铁吸引更近的东西上。But the ball has enough energy from previous accelerations to release the next ball. 但是球从先前有足够的能量释放加速度下个球。However, that ball has less energy than the ball that caused it to release. 然而,那球比球较少的能量就会导致它的释放。It may have enough energy to release another ball or two, but each ball that is released has less energy than before, and eventually the chain stops.它可能有足够的精力去释放另一球或两个,但是每个球有更少的释放的能量比以前,并最终链条停止。

You can show by inductive logic that no matter how many balls you stack in front of each magnet, eventually the system stops.你可以指由无论如何归纳逻辑你洗牌多球门前都用不同的磁铁,最后系统停止。

To estimate the losses due to heating the balls as they compress when hit, consider a plastic tube standing upright on a table. 估计加热造成他们球压缩击中,考虑塑胶管站立在一张桌子。Place one steel ball at the bottom of the tube. 将一个钢球,在底部的管。Now drop another ball into the tube, so it hits the ball at the bottom, and bounces back up.现在舍弃另一球打入管,所以它把球打在底部,能重新振作起来。

Now measure how high the ball bounced. 现在测量球跳多高。If it bounces halfway back up, the losses are 50%. 如果它反弹中途备份,损失50%。Perform the experiment for yourself with the balls from the Gauss Rifle. 做试验,你用把球从高斯步枪。How high does your ball bounce? 你的球是多高蹦蹦跳跳呢?Send me mail with your results.给我寄信件与你的结果。