少儿英语配音《楔子和螺丝》中英文对照课件配音文案
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5000207 Wedges and Screws
5000207楔子和螺丝
Mr. Douglas is making a wooden table and some chairs for the backyard with the help of some simple machines.
道格拉斯先生正在一些简单机械的帮助下,为后院制作一张木制桌子和一些椅子。
Objective:
课程目标:
In this topic we shall learn about the wedges and screws.
在本课题下,我们将会学习楔子和螺丝。
Mr. Douglas is using a log to make the table. He needs to chop the log into smaller pieces. To cut the thick log of wood, he has to use a lot of effort force. To make it easier, he is now using a simple machine, the wedge. A wedge is basically an inclined plane. Wedges may have one or two sloping sides.
道格拉斯先生是使用原木做桌子的。他需要把原木劈成小块。为了切割厚厚的原木,他不得不使用很多的作用力力。为了使其变得更加容易,他现在正在使用一个简单机械-楔子。楔子从根本上来说是一个斜面。楔子可以有一个或两个斜边。
Now let us see how it works. With a knock of the hammer Mr. Douglas has pushed the wedge into the log. Notice, how the effort of pushing it in has caused a spreading force and split the log into two halves. This happens because the force of the hammer pounding on the flat end of the wedge drives the sharp end of the wedge deeper and deeper into the wood. Having cut the log, he needs to scrape off some of the uneven surface with a chisel. A chisel is also a type of wedge. It uses a forward driving force and turns it into a sideways force. The plank is now ready and so are the legs of the table. To assemble the table, Mr. Douglas is using screws. Look at the screw closely. It is an inclined plane wrapped around a cylinder. Like a wedge, a screw moves into the material. Look, after an initial tap on the head of the big screw Mr. Douglas is turning the screw. A screw turns a small rotational force into a larger forward driving force. He is also using some smaller screws to fix the leg properly. The inclined plane of a screw can be steep or shallow. That is, the threads can be far apart as in a big screw or close together as in a smaller screw. The difference is, the farther apart the threads, the faster a screw moves into a material with each turn, but it takes more effort. Looks like the table is almost ready and with this we conclude our lesson on wedges and screws.
现在让我们看看它是如何工作的。达格拉斯先生通过使用锤子敲打把楔子推进原木中。注意,如何把楔子推进去的作用力会产生一个扩张力,并把原木分成两半。这种情况的发生是因为锤子敲打楔子平坦末端的力让楔子的尖端越来越深地打入到木头中去。切割原木后,他需要使用凿子把一些粗糙表面刮掉。凿子也是一种楔子。它是利用向前的推动力,并把它变为侧向力。现在,木板准备就绪了,桌子腿也准备好了。为了组装桌子,达格拉斯先生使用了螺丝。近距离地观看螺丝。它是一个缠绕着圆柱体的斜面。就像楔子一样,螺丝也是运动进入材料中去的。看!在*初轻敲一下大螺丝的平头后,达格拉斯先生在转动螺丝。螺丝把较小的转动力变为较大的向前推动力。他也使用一些较小的螺丝适当地固定桌腿。螺丝的斜面可以是很陡峭或很平缓。也就是说,螺纹可以离得很远,就像是大螺丝中的螺纹,或者螺纹可以靠得很近,就像是较小螺丝中的螺纹。不同的是,螺纹离得越远,每次转动时螺丝进入材料中的速度越快,但是它需要更多的作用力。桌子看上去像是几乎已经做好了,说完这个,我们就结束了我们关于楔子和螺丝的课程。
Summary:
总结:
Wedge is a simple machine.
楔子是一种简单机械。
It is a type of inclined plane.
它是一种斜面。
Wedges can be used to split things apart.
楔子可以用来把物件分开。
Screw is another simple machine.
螺丝是另外一种简单机械。
The screw is also a type of inclined plane.
螺丝也是一种斜面。
A screw turns a small rotational force into a larger forward driving force.
螺丝把较小的转动力变为较大的向前推动力。
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