字幕列表 影片播放 列印英文字幕 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!