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SIMPLE MACHINES

SIMPLE MACHINES. Simple Machines Pre-Quiz. 1.  A fork is an example of a:  pulley      wedge      wheel and axle   2.  A roller skate is an example of a:  wheel and axle      wedge      lever  3.  A ramp is an example of a/an: 

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SIMPLE MACHINES

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  1. SIMPLE MACHINES

  2. Simple Machines Pre-Quiz • 1.  A fork is an example ofa:  pulley      wedge      wheel and axle  •  2.  A roller skate is an example of a:  wheel and axle      wedge      lever  • 3.  A ramp is an example of a/an:  pulley      screw      inclined plane  • 4.  The bottom of a light bulb would be considered a:  lever      screw       wedge  • 5.  A seesaw on the playground is a:  lever       inclined plane       pulley  • 6.  You would use a pulley to:  cut food      hold pieces of wood together  help guide the sail on a sailboat 

  3. Simple Machines A simple machine is a machine that does work with only one movement. Simple machines are tools that make work easier.  They have few or no moving parts.  These machines use energy to work. 

  4. All machines, no matter how complicated, are made of simple machines.

  5. Types of Simple Machines • There are 6 simple machines: • Inclined plane • lever • Wheel and axle • Screw • Wedge • pulley

  6. COMPOUND MACHINES • A machine made up of a combination of simple machines • Ex:

  7. Inclined Planes • Notes to take: • An inclined plane is a simple machine.  • It is a flat surface that is higher on one end.  • You can use this machine to move an object to a lower or higher place.  • Inclined planes make the work of moving things easier.  • You would need less energy and force to move objects with an inclined plane. 

  8. Examples of inclined planes • Ramp • Slanted Road • Path up a Hill • Slide • knife

  9. Wheel and Axle • The wheel and axle is another simple machine. It consist of 2 circular objects of different sizes that are attached in such a way that they rotate together. • It is easy to move things from place to place with wheels and axles • You have probably seen a wheel and axle on a car.  The axle turns when you  put force on the wheel.  • Can you think of a different place that you might find a wheel and axle on a car besides what you see in this picture?  • How about the steering wheel or radio dials?

  10. LEVERS • A lever is any rigid rod or plank that pivots, or rotates, about a point. • Examples of Levers: • A hammer is a lever when it is used to pull a nail out of a piece of wood. • Bottle openers . • Crow bars • Baseball bat Do activity on next slide

  11. Three types of Levers • First class lever: the fulcrum is between the input force and the output force. • 1st class levers multiply force or distance depending on where the fulcrum is placed. They always change the direction of the input force.

  12. 2nd class levers • The output force is between the input force and the fulcrum. • 2nd class levers always multiply the input force but don’t change its direction.

  13. 3rd Class levers • In a 3rd class lever, the input force is between the output force and the fulcrum. • For the 3rd class lever, the output force is less than the input force, but is in the same direction.

  14. The fundamental differences between 1st-,2nd-, and 3rd class levers is the locations of the input force, output force, and fulcrum.

  15. Try this experiment! • Materials: wooden ruler, textbook, and a desktopProcedure: Lay a ruler on your desk with part of it hanging over the edge.  Place a textbook on the other end.  Try to lift the book by pressing down on the part of the ruler that is sticking out.  Repeat this procedure several times.  Move the book closer to the edge by pulling on the ruler.  Continue until the book is right at the table's edge.

  16. Things to think about during the experiment: • -Was it easier to lift the book with a short or long ruler? • -Can you think of a time when you use a simple machine like this? • Conclusion: • The ruler is a lever in this experiment.  The edge of the table is the fulcrum.  And the book is the load.  It is easier to move an object, like the book, when the fulcrum is closer to the load.

  17. Screw • A screw is a simple machine that is made from another simple machine.  • It is actually an inclined plane that winds around itself.  • A screw has ridges and changes the direction of the applied force.   • When you turn a screw, the force applied is changed by the threads to a force that pulls the screw into the material. the threads are, the easier it is to turn the screw.

  18. The mechanical advantage of the screw is the length of the inclined plane wrapped around the screw divided by the length of the screw. • The more tightly wrapped the threads are, the easier it is to turn the screw.

  19. Where would you find examples of a screw? • Jar Lids • Light Bulbs • Stools • Clamps • Jacks • Wrenches • Key Rings • Spiral Staircase

  20. Materials:Nine inch paper square, pencil, tape, marker, tabletop • Procedure:Cut the square in half to make a right triangle.  Use the marker to outline the diagonal side of the triangle.  Now place the paper face down on the table.  Place the pencil on one of the short sides of the triangle.  Wrap the pencil around the triangle.  Use the tape to keep it in place. • Things to think about during the experiment: • -What simple machine is the right triangle? • -What simple machine was created when you wrapped the pencil around the triangle? • -Name some examples of this machine. • Conclusion:You made a screw out of an inclined plane when you wrapped the triangle around the pencil.

  21. Wedge • A wedge is a simple machine used to push two objects apart.  A wedge is made up of two inclined planes.  These planes meet and form a sharp edge.  This edge can split things apart. • You probably use a wedge at lunch every day.  A fork is considered a wedge.  A fork can be used to cut or split food apart.  Can you think of another wedge you use to help you eat?  (How about a knife?)

  22. Examples of wedges: • Knives • Axes • Forks • Nails

  23. Materials:nail, bolt, hammer, block of wood • Procedure:    Try to hammer the bolt into the block of wood.  Think about why a bolt can not be hammered into the wood.  Compare the nail with the bolt.  Now try to hammer the nail into the wood. • Things to think about: • -Why is the nail easier to hammer into the block of wood? • -What simple machine is a nail? • -Can you name some other simple machines with the same characteristics as a nail? • Conclusion:    The nail is a wedge so it is easier to hammer into the wood.  There is a sharp edge on the nail because it has two inclined planes joined together.  This lets the nail separate the wood.

  24. Pulley • This simple machine is made up of a wheel and a rope.  • The rope fits on the groove of the wheel.  One part of the rope is attached to the load.  • When you pull on one side of the pulley, the wheel turns and the load will move.  • Pulleys let you move loads up, down, or sideways.  • Pulleys are good for moving objects to hard to reach places.  • It also makes the work of moving heavy loads a lot easier.

  25. Flag Poles • Clothes Lines • Sailboat • Blinds • Crane

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