ple Machin Sim es Table of Contents
Machines Are All Around Us...... 3
Work, Force, and Load...... 4
Lever...... 6
Wheel and Axle...... 8
Pulley...... 10
Inclined Plane...... 12
Screw...... 14
Wedge...... 16
Conclusion...... 17
Glossary...... 18
2 Machines Are All Around Us
People have used machines for thousands of years. We use machines to get work done. They help us build roads and buildings. They help us move from one place to another.
A machine is anything that is made by people and makes work easier to do. What do you think of when you think of a machine? Many people think of a car or a tractor. Did you know that a hammer and a nail are also machines? A pair of scissors is a machine, too. These are machines because they are made by people. They make work easier to do.
3 Work, Force, and Load
Scientists have special meanings for the words force, work, and load. Let’s learn about these words by thinking about a trip to the grocery store. When you move a grocery cart, you are doing work. You use a force to push or pull the cart. So a force is “a push or a pull”. The cart of groceries is the load. A load is the thing being moved.
force (push or pull)
load
4 Let’s talk about simple machines that help us do work. Simple machines are “simple”. They have one or only a few parts. There are six types of simple machines. They are the lever, wheel and axle, pulley, inclined plane, screw, and wedge. A system is made when a person uses a simple machine to do work. The system is made up of the person and the machine. Work is easier to do when we use simple machines.
System =
Simple Machine + lever wheel and axle pulley inclined plane screw wedge
5 Lever
A lever can be used to move objects. Long ago, people used levers to move large rocks and heavy pieces of wood. Today, we also use levers to move things. A hand cart is a lever. It is very hard work to pick up and move heavy boxes. A hand cart makes it easier.
There are three parts in a lever. They are a fulcrum, a load, and a force. The boxes on the hand cart are the load. These are the objects we want to move. The force is the push or pull used to move the load. The fulcrum is the wheel on the hand cart. Other examples of levers include a seesaw, a tennis racket, and a wheelbarrow.
Hand cart Pull down here and push (force) load
The wheel acts as the fulcrum.
6 Seesaw force (push down) load
fulcrum
Tennis racket load (ball)
fulcrum (wrist) force (push the ball forward here)
Lift up here and push (force)
load Wheelbarrow
The wheel acts as the fulcrum.
7 Wheel and Axle
A wheel and axle is also a simple machine. It moves things from place to place. You know what a wheel looks like. The axle is the rod that runs through the middle of the wheel. The wheel and axle makes work easier. A wheel and axle allows us to roll things instead of carrying them. Think about a grocery cart with wheels and axles. It is easier to move the bag of groceries in a cart than it is to carry it.
8 Grocery Cart
axle wheel
Bicycle Wheel
wheel
axle
9 Pulley
A pulley is a simple machine. It is used to raise and lower a load. A flag pole uses a pulley to raise and lower a flag. A pulley is made up of a wheel with a groove around it. A rope is placed in the groove of the wheel. One end of the rope is hooked to the load. The load is the flag. You pull on the other end. The pull is the force. When you pull down on the rope the flag goes up the pole. You are doing work. Without a pulley, a flag could not be raised up a flagpole.
A pulley is a wheel with a groove around it. The rope sits in the groove. rope groove
wheel
10 A pulley is used on a flagpole.
wheel rope
11 Inclined Plane
A ramp is an inclined plane. An inclined plane is a flat surface that is higher on one end. Think about lifting and moving a heavy box into the back of a truck. It is hard work. It is easier to move the heavy box or load into the truck using an inclined plane. You use less force when you use the ramp.
Look at the picture below. The stairs in the picture form a short and steep slope. The ramp in the picture is longer but not as steep. Which would you rather use to move a heavy load? It would take more force to move the load up the stairs. But you would move the load a short distance. It would take less force to move the load up the longer ramp. But you have to walk farther.
12 Look at the picture below. The hill is an inclined plane. There are two ways to get to the top. Which way would you choose to walk? One side is short and steep. The other side is longer and not as steep. The steep hill is hard to walk up. You are the load that is moving up the hill! The steep hill is the shortest and hardest to climb. More force is needed to move the load. It is easier to walk up the longer side. Less force is needed. However, the same amount of work will have been done once you get to the top.
short and steep longer and not as steep
13 Screw
A screw is an inclined plane wrapped around a metal rod from the bottom to its top. Have you ever used a screwdriver? You turn the screw in a circle but the screw moves down into the wood. The direction of the force has changed. The inclined plane on the screw makes the work easier.
We use screws for many things. Parts of different machines are held together with screws. A drill bit is a kind of screw. It is used to make a hole in something.
Screwdriver turns the drill bit screw in a circle.
rod The screw moves forward into screw the wood. thread
14 An auger (aw-ger) is a large screw. It makes deep holes in the ground. The auger turns in the ground and lifts soil up on its spiral slope. The auger is lifted and emptied when the slopes are full of soil. It is then put back into the ground for another load.
Auger
spiral slope (similar to a screw)
Soil is lifted on the slope.
15 Wedge
A wedge is another kind of inclined plane. A wedge has a thick side and a thin side. An ax is an example of a wedge. The thin edge of the ax does the work. It is used to split wood. The thin edge of the ax pushes the wood apart. The wedge changes the direction of the force. You swing the ax down and the wood splits.
An ax is used to split wood. thick edge wedge
thin edge
Swing ax down into the wood (force).
wood splits slope
16 Conclusion
Machines make work easier. They can help move loads from one place to another. They can change the direction of the force. Machines can also change the force’s strength and speed.
Think about the simple machines we have learned about. Take a look at them. Look closely at their parts. Think about the jobs they do. Remember they make our work easier. They help us get work done.
17 Glossary
Auger a machine shaped like a screw that is used to drill holes in the ground.
Force a push or a pull.
Fulcrum the fixed point on which a lever arm turns or balances.
Inclined plane a flat surface raised on one end, such as a ramp.
Lever a stiff bar that sits or turns on a fulcrum used to raise or move a load.
Load an object to be moved or lifted.
Machine an object made up of parts that each have a job, helps us do work.
Pulley a simple machine that is used to raise or lower a load.
18 Screw a simple machine used for holding things together.
Simple machine a machine with few or no moving parts that helps make work easier.
System a group of parts that work together or interact.
Wedge a simple machine used for splitting or cutting.
Wheel and axle a wheel that turns on a rod called an axle.
Work what is done when force moves an object.
19 Systems and Simple Machines Simple Machines are All Around Us Correlation Fountas & Pinnell K DRA 20 ✯ Estimated Lexile Measure 550L Written under funding from Monroe 2–Orleans BOCES by: Antonietta Quinn, Resource Teacher Danielle Hoch, Reading Specialist Designed and Printed by the BOCES 2 Printing and Graphics Services.
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