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Have you ever
tried to unscrew a nut, bolt, or screw from something with your bare hands and discovered that it was just too tight to loosen even if you had a good grip?
You have probably used some simple machines, but did not realize that they were actually
called simple machines!
Simple machines do not make less work; they just make it easier
to do work.
It would be hard to cut this wood without the saw!
There are 6 different types of simple machines:
•(1)lever
•(2)screw
•(3)pulley
• (4)wheel & axle
• (5)inclined plane
• (6)wedge
(1) LEVER
A lever is a stiff bar that moves about a fixed point (fulcrum).
A lever is used to push, pull, or lift things.
(2) SCREW
A screw is an inclined plane wrapped around a cylinder or cone.
A common use of the screw is to hold objects together.
A jar lid and a wood screw are examples of a screw.
So far we have learned about 2 types of simple machines: levers & screws….
(3) PULLEY
A pulley is a wheel that has a rope wrapped around it.
Pulleys can be used to lift heavy objects by changing the direction
or amount of the force.
A flagpole uses a pulley to raise the flag.
Now we have learned about 3 types of simple machines: levers, screws, and pulleys…..
(4) WHEEL & AXLE
A wheel & axle consists of a rod attached to a wheel.
A wheel & axle makes it easier to move or turn things.
A bicycle wheel, roller skates, and a doorknob are all examples of a wheel
& axle.
We now know about 4 types of simple machines: levers, screws, pulleys, and wheels & axles.
(5) INCLINED PLANE
An inclined plane is a flat surface that is raised so that one end is
higher than the other.
An inclined plane helps move heavy objects up or down.
A ramp is an example of an inclined plane.
Let’s add inclined plane to our list of simple machines (along with levers, screws, pulleys, and wheels & axles).
Now you know about the 6 types of simple machines:
(1) LEVER
(2) SCREW
(6) WEDGE
(3) PULLEY
(4) WHEEL & AXLE
(5) INCLINED
PLANE
Can you think of other examples of pulleys?
• Did you say either of these:
A pulley that raises and lowers blinds.
The pulley that raises and lowers the flag on a flagpole.
The inclined plane is a simple machine.
• An inclined plane is a slanted surface that can be used to raise or lower things.
• An inclined plane does not move.
Can you think of other examples of inclined planes?
• Did you say any of these?
dump truck ladder rollercoaster
A wedge is a type of simple machine.
• A wedge is two inclined planes that are back to back.
• The difference between an inclined plane is that it does its work by staying still, while a wedge moves.
• Wedges hold things together or split things apart.
A screw is a type of simple machine.
• A screw is an inclined plane that is wrapped around a cylinder with a flat head on one end.
• This head is used to turn or drive the screw into something.
As you can see, our world is made up of many simple machines. You can find examples any place you
look.
• Simple machines solve the problem of how to do work faster and easier.
• Maybe you can invent a machine that will make some job faster and easier.
Pulleys
• Pulley are wheels and axles with a groove around the outside
• A pulley needs a rope, chain or belt around the groove to make it do work
Diagrams of Pulleys
Fixed pulley: A fixed pulley changes the direction of a force; however, it does not create a mechanical advantage.
Movable Pulley: The mechanical advantage of a moveable pulley is equal to the number of ropes that support the moveable pulley.
COMBINED PULLEY
• The effort needed to lift the load is less than half the weight of the load.
• The main disadvantage is it travels a very long distance.
Fulcrum
Lever
Load
Click Here to Learn More
Click on the dude to learn more.
A screw is an inclined plane wrapped around a post. Click on the light bulb to learn more.
Two inclined planes make a wedge.
Try to catch the saw to learn more.
Axle
Wheel
Click on the windmill to learn more.
Wheel
Rope This box is easier to lift because of the pulley. Click on it to learn more.