simply_machines

Simple Machines Experiments

Index Gears

3

Inclined Plane

4

Levers

5

More Levers!

7

Pull Toy

8

Pulleys

9

Simple Pulleys

10

Skateboards: Simple Machines

11

What Do Wedges Do?

12

Supply List

13

Simple Machines

14

References

15

Children’s Literature

16

Notes

17

Gears

Index

Gears are wheels with teeth on the outer portion of the rim. The gear moves about an axle, which is a rod or shaft fitted into the center of the gear. This experiment is designed to show how gears can be used to change the direction of motion of an object or change the speed of an object. All wheels move and do work by rotating.

Materials

Gear factory stages Mulitplier stages

What To Do

Use the gear factory stages first. Count the number of teeth on each gear. When the gear on the left is rotated once, count the number of times the other gear rotates. Use all three stages (small gear with medium gear, two gears of the same size, and large gear with small gear). Next monitor the rotation of the gears. If the first gear moves clockwise, what happens to the second gear?

What direction will a third gear rotate if connected to the second gear? Next try the multiplication machine which has a large gear connected to a medium size gear connected to a small gear. If the large gear is turned one rotation how many rotations of the small gear occur? If the large gear is turned two rotations, how many rotations of the small gear occur?

Questions

1. Using the information above, if the large gear is rotated four times, how many times will the small gear rotate?

2. Write your own multiplication problem and test it with the multiplication machine.

Source

Unknown Š S. Olesik, WOW Project, Ohio State University, 2001.

Inclined Plane

Index

Inclined planes are useful in many ways, more than are usually noticed. Inclined planes, like all simple machines, make work easier. The goal of this experiment is to demonstrate how an inclined plane lowers the amount of force needed to raise objects.

Materials

3 boards (12, 24, and 36 inches long) Pile of books or support for the boards 200 gram weight Spring scale or clamp pulley Paper or plastic cup Gram weights

What To Do

First use the spring scale to measure the force needed to lift the weight straight up from the tabletop to the top of the books or support. Form an inclined plane between the tabletop and top of the pile of books. Slide the weight up the inclined plane from the tabletop to the top of the pile of books. Measure the force needed to move the weight using the spring scale or by adding the gram weights to the cup, which is connected to the weighted string that is threaded through the pulley.

Measure the force necessary to move the weight using all three boards.

Question

1. Which board required the least applied force to move the weight to the top of the pile of books?

Why?

Extension

You are an engineer for the space station; make a drawing that illustrates the use of inclined planes on the space station.

Make a list of inclined planes in your house.

Summary

Inclined planes trade distance for applied force. Examples of other inclined planes-stairs, wheelchair ramps, roads that wind up mountains, and screws (a screw is an inclined plane wrapped around a shaft).

Source

“Machines.” Janice Van Cleave, John Wiley, and Sons, New York. ISBN:0-471-57108-3.

“Bathtubs, Slides and Roller Coaster Rails: Simple Machines That Are Really Inclined Planes.” Christopher Lampton, Millbrook Press, 1991. ISBN: 1-878841-23-8. © S. Olesik, WOW Project, Ohio State University, 2001.

Grade Level: Appropriate for grades K through 5.

Levers

Index

Archimedes once said, “Give me a place to stand and I can move the world.” What he meant was that if he could stand far enough away from the earth he could use a lever to move it. Levers use distance to make heavy objects easier to move. The goal of this experiment is to demonstrate how a lever reduces the amount of force needed to move objects.

Materials

1 yardstick, cut in half 1 pencil 3/8” galvanized washers Double-sided tape

Vocabulary

Fulcrum: Point about which a lever turns or pivots Effort arm: Distance from fulcrum to point where force is applied Load arm: Distance from fulcrum to point where load is applied

What To Do

Use the pencil as the fulcrum and the 1/2 yardstick as the lever. Use double sided tape to secure the pencil to a table. Use 5 washers as the load. Weigh the total number of washers that are used as the load. Place the load at the very end of the piece of wood. Place the dowel rod under the plank of wood at the center point (9” from one end). Measure the distance between the fulcrum and the load (i.e. How long is the load arm?). Place washers one by one on the opposite end of the lever. How many washers must be added to exactly balance or begin to tip the load washers on the other end? Weigh the washers that just balance the load. Remove the washers and move the fulcrum to 4 1/2 inches from the load end of the lever. Place a five washer load on the lever and place washers one by one on the opposite end of the lever until the load is balanced or begins to tip. How many washers were used to balance the load? How much did they weigh? Remove the washers and move the fulcrum to 13 1/2 inches from the load end of the lever. Place a five washer load on the lever and place washers one by one on the opposite end of the lever until the load is balanced or begins to tip. How many washers were used? How much did they weigh?

Questions

1. Which position of the dowel rod required the least number of added washers to tip the load?

2. Make a plot number of washers or total weight of washers used to balance the load versus distance between the fulcrum and the load for each measurement. Can you predict using this graph what weight of washers is required to lift the load washers if the fulcrum is placed 15” away from the load?

Summary

Levers lift objects easiest when the fulcrum is as close to the load end as possible. There are four components of a lever system: 1) the lever (a bar or rod), 2) the fulcrum, 3) the load, and 4) the force used to balance the load.

There are three possible ways of ordering the load, fulcrum and the force, which corresponds to the three different classes of levers.A first class lever has the fulcrum placed between the load and the balancing force. The balance that was studied in this experiment is a first class lever. A second class lever has the load located in the middle and the fulcrum and the balancing force on opposite ends. Examples of second class levers: a wheelbarrow, hand truck, wrench, nutcracker, and the handle to a pencil sharpener. A third class lever has the balancing force in the middle with the

load and fulcrum on opposite ends. Commonly used third class levers include arms, legs, cranes, catapults, and fishing poles.

Extension

What class levers are: a hammer, a crowbar, a seesaw, and a ring pull top on a soda can?

Draw a diagram of a lever system and label the four components.

Design a toy using a lever in some part of the toy.

Source

“Making Science Work: Forces and Machines.” Terry Jennings, Raintree Steck-Vaughn Company, Austin, 1996.

ISBN: 0-8172-3961-8.

“Investigate and Discover Forces and Machines.” Robert Gardner, Julian Messner Press, Englewood Cliffs, 1991. ISBN: 0-671-69046-9.

“Starting with Science: Simple Machines.” Deborah Hodge, Kids Can Press, Buffalo, 1998. ISBN: 1-55074399-6.

“Simple Machines Made Simple.” Ralph St. Andre, Teachers Ideas Press, 1993. ISBN: 1-56308-104-7. © S. Olesik, WOW Project, Ohio State University, 2001.

Grade Level: This experiment is expected to be appropriate for grades 3 and above.

More Levers!

Index

Archimedes once said, “Give me a place to stand and I can move the world.” What he meant was that if he could stand far enough away from the earth he could use a lever to move it. Levers use distance to make heavy objects easier to move. The goal of this experiment is to demonstrate how a lever reduces the amount of force needed to move objects.

Materials

1 ruler 1 pencil 1 heavy book Vocabulary Fulcrum: Point about which a lever turns or pivots Effort arm: Distance from fulcrum to point where force is applied Load arm: Distance from fulcrum to point where load is applied

What To Do

Use the pencil as the fulcrum and the wooden ruler as the lever. Place the pencil at the 6” mark on the ruler. Use a book as the load. Support a book at one end of the ruler. Push down on the opposite end of the ruler to lift the book. Now place the pencil at the 9” mark on the ruler and repeat. Now place the pencil at the 3” mark on the ruler and repeat.

Questions

1. Which position of the pencil makes it easiest to pick up the book?

2. How does the ratio of the effort arm/load arm affect the amount of force that must be applied?

Summary

Levers lift objects easiest when the fulcrum is as close to the load end as possible.

Examples of other levers- Wheelbarrow, hammer, crowbar, seesaw, and the ring pull tops on a soda cans.

Source

“Making Science Work: Forces and Machines.” Terry Jennings, Raintree Steck-Vaughn Company, Austin, 1996.

ISBN: 0-8172-3961-8.

“Investigate and Discover Forces and Machines.” Robert Gardner, Julian Messner Press, Englewood Cliffs, 1991. ISBN: 0-671-69046-9.

“Starting with Science: Simple Machines.” Deborah Hodge, Kids Can Press, Buffalo, 1998. ISBN: 1-55074399-6. © S. Olesik, WOW Project, Ohio State University, 2001.

Pull Toy

Index

The goal of this experiment is to demonstrate the combined use of multiple movable pulleys.

Materials

2 7/8” diameter dowel rods 20’ of rope or more

What To Do

Tie the rope around the barrel of one of the dowel rods.

Have two students hold the dowel rods parallel to each other. The dowel rods should be about 2 feet apart. Next, wrap the rope back and forth between the two dowel rods two times. While the students holding the dowel rods try to pull them away from each other, ask another student to pull on the loose end of the rope to try to pull the dowel rods together. Wrap the rope back and forth between the dowel rods four more times. Ask the students to try pulling again. Does it feel different this time? Wrap the rope back and forth between the dowel rods four more times and try again.

Questions

1. Which student controls the distance between the two rods?

2. Why? 3. What does this tell us about how pulleys work?

Summary

Each time the rope travels from one dowel rod to the next the force necessary to move the rod decreases because each wrapping of the rope acts as a pulley. If there are four complete loops across, that corresponds to 8 strands moving from one rod to the next. The force necessary to move the rods is divided evenly between the number of strands of rope. Therefore the force necessary to move the rods should be decreased by a factor of 8 with 8 strands.

Source

“Pulley Activities.” NES Arnold, World Class Learning Materials, Baltimore, ISBN: 1-884461-08-5.

“Simple Machines Made Simple.” Ralph St. Andre, Teacher Ideas Press, 1993, ISBN: 1-56308-104-0. © S. Olesik, WOW Project, Ohio State University, 2001.

Grade Level: Grades K-5

Pulleys

Index

The goal of this experiment is to demonstrate how pulleys lower the amount of applied force necessary to move a load.

Materials

1 7/8” diameter dowel rod 3 pulleys 1 500 gram weight 1 spring balance or a pail or cup with gram weights Rope

What To Do

First use a spring balance to measure the amount of force needed to raise the 500 g weight to a specified height.

Next attach a clamp pulley to the dowel rod and attach the weight to the pulley, measure how much force is needed raise the 500 g weight to the same height as in part 1. Try to measure the length of rope that you pulled to get the weight to move to the desired height.

Add a second pulley to the system, and again measure the amount of force needed to raise the weight to the same height as in the two previous measurements. Again try to measure the length of rope that you pulled to get the weight to move to the desired height.

Add a third pulley to the system and again measure the amount of force needed to raise the weight to the same height as in the previous sections.

Questions

1. Compare the information collected in parts 1, 2, 3 and 4.

2. Does it make any difference whether you use one, two or three pulleys to raise the load?

3. Compare the length of rope needed to raise the load in each case. What trend do you observe in your data?

4. Calculate the mechanical advantage of using the two and three pulley systems.

Summary

The use of one pulley only changes the direction of the applied force. When two pulleys are used, the force necessary to raise the weight should be approximately half that needed when using the single pulley. However, friction causes the addition of extra effort. Pulleys trade force necessary to do work for the distance traveled. The distance that the rope had to be pulled with the second pulley should have been approximately twice that used with one.

Add a third pulley to the system. Now there are three sections of rope that have to move up before the load moves. For this case, the force (or effort) necessary to raise the load should be 1/3 that which is needed with one pulley.

Source

“Science Factory: Work and Simple Machines.” Jon Richards, Cooper Beech Books, Brookfield, 2000. ISBN: 0-7613-1159-9 “Pulley Activities.” NES Arnold, World Class Learning Materials, Baltimore, ISBN: 1-884461-08-5. © S. Olesik, WOW Project, Ohio State University, 2001.

Grade Level: This experiment is expected to be appropriate for grades 3 and above.

Simple Pulleys

Index

Pulleys can be used to reduce the amount of force needed to do work or to change the direction of the force. This activity provides a simple example to help young students understand pulleys and their functions.

Materials

Broom handle or thick dowel rod Rope Milk bottle or detergent bottle with handle, filled with water or sand

What To Do

Secure the ends of the dowel rod to the tops of two desks spaced about 3 feet apart.

Hang the rope over the dowel rod and tie one end of the rope to the handle of the milk jug.

Pull down on the other end of the rope to lift up the milk jug. This is a fixed pulley system that is used to change the direction of the force needed to lift the milk jug. Untie the milk jug. Thread the end of the rope through the handle of the jug, and then tie that end of the rope to the dowel rod. Lift up on the loose end of rope to lift up the milk jug. This is a movable pulley system.

How does the amount of force used here compare to the amount used to lift the jug in step 3?

Loop the loose end of rope over the dowel rod and pull the end down to lift the milk jug. This is a combination of movable and fixed pulley systems. Does this arrangement of pulleys make it easier to lift the milk jug? Try looping the loose end of the rope over the dowel rod one or two more times. Is it easier to lift the milk jug?

Question

1. Do pulleys make it easier to work? How?

Source

“Sailboats, Flagpoles, Cranes: Using Pulleys as Simple Machines.” Christopher Lampton. Millbrook Press, Brookfield: 1991. ISBN 1-56294-026-0 © S. Olesik, WOW Project, Ohio State University, 2003.

Skateboards: Simple Machines

Index

A wheel and axle is a simple machine that is actually a modification of a pulley. Like the pulley, the wheel and axle makes work easier by reducing friction. The wheel and axle must function together to be a simple machine.

Materials

Skateboard Group of at least 3 students Flat and smooth floor surface

What To Do

Place the skateboard wheel-side-up on the floor. Ask one student, the rider, to stand on the skateboard. Choose another student in the group to be the mover, the one who will apply the force. All other students in the group will be protectors, making sure that no one will fall during the experiment. Instruct the mover to push on the skateboard to try to move the rider 2-3 feet across the floor while the protectors help stabilize the rider. Ask for observations from all students in the group. Turn the skateboard over so that the wheels are in contact with the floor.

Instruct the same rider to stand on the skateboard. While the protectors provide stability for the rider ask the mover to again push the skateboard to try to move the rider 2-3 feet across the floor. Share and discuss observations.

Question

1. Was it easier for the mover to move the rider when the skateboard was placed wheel-side- up or wheel-side-down? Why?

Summary

The wheel and axle is a simple machine that reduces friction to make work easier. Students will have a much easier time moving their classmates on a skateboard with wheels down than with wheels up!

Source

“Marbles, Roller Skates, and Doorknobs: Simple Machines That Are Really Wheels.” Christopher Lampton.

Millbrook Press, Brookfield: 1991. ISBN: 1-878841-24-6. © S. Olesik, WOW Project, Ohio State University, 2003.

What Do Wedges Do?

Index

A wedge is a simple machine that is actually part of a subset of inclined planes. What makes the wedge special is how it is used. Inclined planes make it easier to raise things, but when an inclined plane is used as a wedge, what does it do?

Materials

Large box full of uncooked rice Rectangular block Triangular block Pictures of examples of wedges (Bow of a boat, ax splitting wood, knife cutting through cheese or butter, etc.)

What To Do

Place the box of rice on the table and smooth the surface of the rice so it is evenly distributed.

Place the rectangular block in the rice at one end of the box. Make sure the block is submerged/ embedded in the rice. Push the block to the other end of the box, paying close attention to the amount of effort used. Also notice what happens to the rice as the block is pushed through it.

Remove the rectangular block from the rice and again smooth the rice so it is evenly distributed.

Place the triangular block in the rice at one end of the box with the base of the triangle toward the wall and the point of the triangle facing the opposite end of the box. Make sure the block is submerged/embedded in the rice. Push the block to the other end of the box, paying close attention to the amount of effort used. Also observe what happens to the rice as the block is pushed through it. Did you notice any differences?

Questions

1. Was it easier to move the rectangular block or the triangular block through the rice? (Triangular) 2. What happened to the rice as the triangular block was pushed through it? Where did it go? (It was pushed to the sides) 3. What do wedges do? (Spread things apart)

Summary

Wedges are inclined planes that split things apart. When woodcutters split wood they pound a wedge into the log to force it apart. Knives are also wedges, and so are the bows of boats and ships, cutting through water to make it easier for the ship to move forward. This activity was designed to help students understand that wedges are used to push things apart, and to reduce the force needed to do so.

Source

“Bathtubs, Slides, and Roller Coaster Rails: Simple Machines That Are Really Inclined Planes.” Christopher Lampton. Millbrook Press, Brookfield: 1991. ISBN: 1-878841-23-8. © S. Olesik, WOW Project, Ohio State University, 2003.

Index

Supply List Gears (Gear Stages) Gear factory stages Mulitplier stages

Inclined Plane

3 boards (12, 24, and 36 inches long) Pile of books or support for the boards 200 gram weight Spring scale or clamp pulley Paper or plastic cup Gram weights

Levers

1 yardstick, cut in half 1 pencil 3/8” galvanized washers Double-sided tape

More Levers!

1 ruler 1 pencil 1 heavy book

Pull Toy

2 7/8” diameter dowel rods 20’ of rope or more

Pulleys

1 7/8” diameter dowel rod 3 pulleys 1 500 gram weight 1 spring balance or a pail or cup with gram weights Rope

Simple Pulleys

Broom handle or thick dowel rod Rope Milk bottle or detergent bottle with handle, filled with water or sand

Skateboards: Simple Machines Skateboard Group of at least 3 students Flat and smooth floor surface

What Do Wedges Do?

Large box full of uncooked rice Rectangular block Triangular block Pictures of examples of wedges (Bow of a boat, ax splitting wood, knife cutting through cheese or butter, etc.)

Simple Machines

Index

Inclined Plane Screw Wedge Lever Pulley Wheel and Axle Machines are used by humans to help them do work. Simple machines are used to lower the amount of force needed to do work or change the direction of a force. If less force is applied, the force must be applied over a longer distance.

Work = Force x Distance Force is a push or pull.

Simple machines are trading distance for force.

The amount of work done is always the same - scientists call this conservation. This means that to do the same amount of work, someone can either exert a lot of force over a small distance or a little bit of force over a big distance. The equation “work = force x distance” works great on paper; however, in the real world this isn’t precisely true. The truth is, when we use simple machines we introduce friction. Therefore, the amount of work done is a little bigger using a pulley to lift something (small force, big distance) than just lifting it by arm (big force, small distance). The trade-off is still in effect, but because of friction there is a slightly larger amount of work involved. © S. Olesik, WOW Project, Ohio State University, 2001.

References

Index

“Machines.” Janice Van Cleave, John Wiley, and Sons, New York. ISBN:

0-471-57108-3 “Bathtubs, Slides and Roller Coaster Rails: Simple Machines That Are Really

Inclined Planes.” Christopher Lampton, Millbrook Press, 1991. ISBN:

1-878841-23-8 “Making Science Work: Forces and Machines.” Terry Jennings, Raintree Steck-

Vaughn Company, Austin, 1996. ISBN: 0-8172-3961-8 “Simple Machines Made Simple.” Ralph St. Andre, Teachers Ideas Press, 1993.

ISBN: 1-56308-104-7 “Starting with Science: Simple Machines.” Deborah Hodge, Kids Can Press,

Buffalo, 1998. ISBN: 1-55074-399-6 “Investigate and Discover Forces and Machines.” Robert Gardner, Julian Messner

Press, Englewood Cliffs, 1991. ISBN: 0-671-69046-9 “Science Factory: Work and Simple Machines.” Jon Richards, Cooper Beech Books,

Brookfield, 2000. ISBN: 0-7613-1159-9 “Pulley Activities.” NES Arnold, World Class Learning Materials, Baltimore. ISBN:

1-884461-08-5 “Marbles, Roller Skates and Doorknobs: Simple Machines That Really Work.”

Christopher Lampton, Millbrook Press, 1991. ISBN: 1-878841-24-6 Unknown.

Children’s Literature

Index

“Simple Machines.” By Melvin Berger. Newbridge Educational Publishing: New York, 1995. ISBN

1-56784-128-7.

“Simple Machines.” By Allan Fowler. Children’s Press: New York, 2001. ISBN 0-516-27310-8.

“Levers.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN 1-57572-080-9.

“Pulleys and Gears.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN

1-57572-084-1.

“Ramps and Wedges.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN

1-57572-083-3.

“Screws.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN 1-57572-085-X. “Springs.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN 1-57572-082-5.

“Wheels and Cranks.” By David Glover. Rigby Interactive Library: Crystal Lake, 1997. ISBN

1-57572-081-7.

“Simple Machines.” By Deborah Hodge, photographs by Ray Boudreau. Kids Can Press: Tonawanda,

1998. ISBN 1-55074-399-6.

“Bathtubs, Slides, Rollercoaster Rails: Simple Machines That Are Really Inclined Planes.” By

Christopher Lampton, illustrated by Carol Nicklaus. The Millbrook Press: Brookfield, 1991.

ISBN 1-878841-44-0.

“Marbles, Roller Skates, Doorknobs: Simple Machines That Are Really Wheels.” By Christopher Lampton, illustrated by Carol Nicklaus. The Millbrook Press: Brookfield, 1991. ISBN

1-878841-45-9.

“Sailboats, Flagpoles, Cranes: Using Pulleys as Simple Machines.” By Christopher Lampton,

illustrated by Carol Nicklaus. The Millbrook Press: Brookfield, 1991. ISBN 1-56294-026-0.

“Seesaws, Nutcrackers, Brooms: Simple Machines That Are Really Levers.” By Christopher

Lampton, illustrated by Carol Nicklaus. The Millbrook Press: Brookfield, 1991. ISBN

1-878841-22-X. “Science Magic With Machines.” By Chris Oxlade. Aladdin Books Ltd.: London, 1994. ISBN

0-8120-9368-2.

“The Usborne Internet-Linked Library of Science: Energy, Forces & Motion.” By Alastair Smith and

Corrine Henderson. Usborne Publishing: London, 2001.

“The Usborne Illustrated Encyclopedia: Science and Technology.” Usborne Publishing: London, 1996.

“Machines At Work.” By Alan Ward. Franklin Watts: New York, 1993. ISBN 0-531-14243-4.

“How Do You Lift a Lion?.” By Robert Wells, illustrated by the author. Albert Whitman & Company: Morton Grove, 1996. ISBN 0-8075-3419-6.

Notes

Index

There are currently no notes on this unit. If you have suggestions or changes to make on the experiments or units, please email us! Our address is wow@chemistry.ohio-state.edu. Š S. Olesik, WOW Project, Ohio State University, 2002.

Copyright Š 2002-2010 by S.Olesik, Wonders of Our World Project (WOW), the Ohio State University. Permission to make digital or hard copies of portions of this work for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page in print or the first screen in digital media. Abstracting with credit is permitted.