Simple Machines Mechanical Advantage

[Music] [Music] [Music] look carefully we're going to find the machines in this yard Mr Simmons is building new stairs for his porch he's going to use a board to help him walk up and down until the stairs are built did you see the machine he was using over here in the yard Ronnie Simmons is playing with his friend dick on the Seesaw do you see the machine they're using we've really been looking at machines but perhaps they're not the kinds of machines you're used to so let's think about Machin you're familiar with in front of the house a street sweeping machine is going by it has many parts with its big turning brush it makes the work of sweeping the streets very easy for this man a lawnmower is a machine too it makes the work of cutting grass easier now let's see if we can say what a machine is a machine is something that helps us do work now let's see if we can find machines in the backyard while Ronnie and Dick play on the Seesaw we're going to see something that helps Billy do his work Billy has a box of groceries to deliver to Mrs Simmons but getting up on the porch without the stairs seems like hard work that's why Billy is going to walk up the slanted board the board makes the work easier because the board is helping Billy do work it is called a machine it is a machine that is made of only one part we call it a simple machine when the board is used in this way we call it an inclined plane one important kind of simple machine Let's look for another simple machine here at the Seesaw do you see anything that is helping someone do some work well the Seesaw is we'll see how now that Paul is here Paul is much bigger than either dick or Ronnie Paul can easily lift dick do you think dick can lift Paul not very easily Paul is too heavy but there is a way for dick to lift Paul he'll use the Seesaw with Paul sitting nearer to the middle of the board than dick is Dick can lift him with a weight of his body the Seesaw makes the work of lifting Paul easier so the Seesaw is a machine it doesn't have many parts like the slanted board the Seesaw is also called a simple machine when a board is used like this it is called a lever a lever is the second important kind of simple machine now that we know that simple machines help us do work let's see just how they do this Ronnie wants to get something from his house but instead of walking up the long board he's going to try walking up a shorter board Ronnie will have to walk just a short distance to get to the top but it's such hard work that Ronnie can't get to the top it is much easier to walk up the longer board but notice that Ronnie has farther to go the short board didn't make the work of getting on the porch easy enough the longer an inclined plane is the easier the work is a lever makes work easier in the same way while dick is able to lift Paul on the Seesaw he moves Paul only a short distance up and down yet dick has to move his end of the Seesaw a long distance this is one way that a lever makes work easier watching Ronnie we'll see another way that a lever helps us do work a baseball bat is a kind of lever when Ronnie swings the bat like this you can see that the two ends of the bat move something like a seesaw while the handle end of the bat moves a small distance the other end of the bat moves a longer distance in the same time so it moves faster so simple machines sometimes help us do things faster than we could by ourselves all simple machines are either something like a lever or something like an inclined plane we will see one example now Freddy's car isn't working very well the steering wheel has come off to steer the car he has to turn this part which is called an axle but Freddy can't turn the axle with just his [Music] hands Ronnie can't either even Mr Simmons can't but with his pliers he can Mr Simmons is using the pliers as a kind of lever to help him turn the axle and the axle will be even easier to turn with the steering wheel in place there each spoke of the wheel is something like the pliers fastened to the axle now do you see all the spokes are levers that make the work of turning the axle easier the wheel and the axle together make up a simple machine that is called a wheel and axle there was someone else in the backyard who is using a simple machine Mrs Simmons instead of having to walk along the line to hang her laundry she can just pull the line toward her that makes her work much easier pulling the line toward her moves the laundry away from her this happens because the clothes line goes around this little wheel it's a simple machine called a pulley a pulley is also something like a lever now that we've seen simple machines that are something like a lever let's look at some that are something like an inclined plane Mr Simmons seems to be having some trouble the nail isn't going into the wood very easily now he knows why the nail doesn't have a point but this one does now it's much easier to hammer the nail into the wood the point of the nail is a simple machine that makes the work easier let's look at a point very closely its sloping sides are like inclined planes the point of a nail is a simple machine called a wedge wedges are made up of inclined planes that move when the wedge is used now Mr Simmons is going to make a hole in the board where he is drawing the circle Ronnie thinks his father will use this tool this isn't really the one Mr Simmons wanted but he will show Ronnie how it could be used this tool a chisel is a kind of wedge too its sharp edge is an inclined plane with a chisel Mr Simmons could cut a hole in the wood but there's a much easier way of doing it he's going to use this tool a brace and bit let's look at the bit the part that will make the hole the edge of the tool is an inclined plane like a chisel that will cut into the wood then the inclined plane goes around this part that goes around also helps to make the work of cutting a hole in the wood easier it is a kind of simple machine that is called a screw a screw is a simple machine that moves an inclined plane around and [Applause] around all tools and more complicated Machines are made up of simple machines all simple machines are either something like an inclined plane or something like a lever simple machines make work easier or help us do things faster nearly all the work we do is done with the help of some kind of simple machine [Music]