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  • Squeaks and I are exploring!

  • We're looking for insects!

  • We know that some insects make their homes under rocks.

  • So we're trying to turn over a couple of these rocks to see what we can find!

  • But they're really big and heavy, and

  • we can't get either of them turned over.

  • There has to be something we can do.

  • Great idea, Squeaks!

  • A few weeks ago, we used a tool called a ramp to help us do work.

  • A ramp, which looks a lot like a slide, is one kind of simple machine.

  • Like all machines, a simple machine is just something that makes work easier.

  • That ramp sure helped us move those books into the house!

  • And there's another simple machine that we can use to help us to turn over those rocks!

  • This one is called a lever.

  • A lever basically looks like this: a long bar that's balanced on something underneath.

  • And that something is called a fulcrum.

  • By pushing down on one end of the lever, the fulcrum makes the other end go up.

  • Just like a see-saw at the playground!

  • It's just a long bar, that's balanced on a fulcrum.

  • Levers make work easier, by helping us lift things that would be too heavy to lift

  • on our own.

  • If Squeaks hops on the low end of the seesaw, and I push down on the high end, the lever

  • moves on the fulcrum, and I can lift Squeaks up.

  • It's a lot easier for me to lift Squeaks this way, than if I tried to just pick him up.

  • Our simple machine made my job easier!

  • So let's use a lever to see if it can help us lift up these rocks!

  • Alright, we'll put one end of the lever under the edge of this first rock.

  • Next, we'll use this smaller rock as our fulcrum, and put it under the middle of the

  • lever.

  • Now we can push on the high end of the lever and the rock goes up!

  • Look we did it! But it was still kind of hard.

  • I wonder if there's something we can do to make the job even easier?

  • Let's try something a little different for the second rock.

  • This time, we'll put the fulcrum closer to the rock we want to lift.

  • Let's set up our lever, give the high end a good push down, and... Bingo!

  • That was a lot easier.

  • For levers like this one, the closer the fulcrum is to the thing you want to lift, the easier

  • it is to lift it!

  • And that's what makes a lever a kind of simple machine!

  • Even though it's super-simple, a lever helps us do work!

  • Levers are everywhere, and they sometimes don't look much like a see-saw, or even

  • like the lever we used to lift our rocks.

  • For example, did you know that when you use a wheelbarrow to carry something, you're

  • using a kind of a lever?

  • It's true!

  • The wheel of the wheelbarrow acts as the fulcrum, and instead of pushing down on the handles,

  • you pull them up to lift what's inside!

  • We use levers to open bottles, too, and to dig in our gardens, and even to eat our food!

  • We'll be back soon with more simple machines, but in the meantime, Squeaks and I have some

  • insects to find!

  • Thanks for joining us on SciShow Kids!

  • Do you have a question about machines, or insects, or anything else at all?

  • Ask a grownup for help, and leave us a comment below, or send us an email to kids@theSciShow.com!

  • And we'll see you next time!

Squeaks and I are exploring!

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B2 中高級 美國腔

超级简单的机器:杠杆(Super Simple Machines: Levers)

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    joey joey 發佈於 2021 年 05 月 07 日
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