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Simple Machines

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Simple Machines

  1. 1. Simple Machines Done By : Leow Wei Sheng (15)
  2. 2. Introduction <ul><li>Simple machines are machines that help people do work with less effort, more conveniently and more quickly. </li></ul><ul><li>All machines are made up of one or more simple machines. </li></ul><ul><li>Simple machines include levers, pulleys, wheels and axles, wedges, inclined planes and gears. </li></ul>
  3. 3. History of Simple Machines <ul><li>The lever was first described in about 260 BC by the ancient Greek mathematician Archimedes, who lived from 287-212 BC. </li></ul><ul><li>Archimedes also invented the compound pulley, which is a combination of fixed and movable pulleys. However, there are no records of who invented the pulley. </li></ul>
  4. 4. History of Simple Machines <ul><li>The civilisation of the Sumerians in Mesopotamia was recorded as the first people to use the wheel and axle, when they invented the two-wheeled cart. However, on one is sure who exactly invented the wheel and axle. </li></ul>
  5. 5. History of Simple Machines <ul><li>The people of the early stone age invented and used the wedge. </li></ul><ul><li>The inclined plane is probably the earliest of the six simple machines to be invented, in the early stone age. </li></ul>
  6. 6. History of Simple Machines <ul><li>The gear was invented long ago, no one is sure who invented it. However, it has been used in machines ever since. </li></ul>
  7. 7. Levers <ul><li>A lever is a stiff bar that rests on a support called a fulcrum which lifts or moves loads by applying effort at a specific part of the bar. </li></ul><ul><li>There are three different classes of levers: first class, second class and third class levers. </li></ul>
  8. 8. Levers <ul><li>In first class levers, the fulcrum is between the effort and the load. Examples are: pliers and see-saws. </li></ul>
  9. 9. Levers <ul><li>In the second class lever, the load is between the fulcrum and the effort. Examples are: wheelbarrows and nut crackers. </li></ul>
  10. 10. Levers <ul><li>In the third class lever, the effort is between the fulcrum and the load. Examples are: fishing rods and tongs. </li></ul>
  11. 11. Pulleys <ul><li>A pulley is a simple machine that uses grooved wheels and a rope to raise, lower or move a load. </li></ul><ul><li>There are two types of pulley: fixed and movable pulleys. </li></ul>
  12. 12. Pulleys <ul><li>Advantages of a fixed pulley: changes the direction of the effort. </li></ul><ul><li>Disadvantages of a fixed pulley: does not reduce effort, is attached to a support. </li></ul><ul><li>Advantages of a movable pulley: reduces effort, attached to the load and moves together with it. </li></ul><ul><li>Disadvantages of a movable pulley: does not change the direction of the effort. </li></ul>
  13. 13. Pulleys <ul><li>There are also compound pulleys, which is made by combining the fixed and movable pulleys into one pulley. </li></ul><ul><li>A compound pulley have the advantages of both the fixed and movable pulleys. </li></ul>
  14. 14. Wheels and Axles <ul><li>The wheel and axle consists of a large wheel that is joined to a rod called the axle. </li></ul><ul><li>We usually turn the wheel to move the axle. </li></ul>
  15. 15. Wheels and Axles <ul><li>The wheel is usually bigger than the axle. </li></ul><ul><li>A smaller effort at the wheel can overcome a greater load at the axle. </li></ul><ul><li>Examples of wheels and axles: doorknobs and windmills. </li></ul>
  16. 16. Wedges <ul><li>A piece of material that is thick at one edge and tapered to a thin edge at the other for insertion in a narrow crevice, used for splitting, tightening, securing, or levering. </li></ul><ul><li>Examples of wedges are: knives and axes. </li></ul>
  17. 17. Inclined Planes <ul><li>An inclined plane is a slanting surface connecting a lower level to a higher level. </li></ul><ul><li>Instead of lifting the load up vertically from the ground, moving it over a greater distance uses less effort. </li></ul><ul><li>Examples of inclined planes: ramps, stairs and screws. </li></ul>
  18. 18. Gears <ul><li>A gear is a wheel, but with cut teeth of equal form, size, and spacing. </li></ul><ul><li>Used in machines to connect one part of a machine with another part. </li></ul><ul><li>Examples of machines that need gears to work: bicycles and cars. </li></ul>
  19. 19. Thank You!
  20. 20. References <ul><li>http://www.enchantedlearning.com/physics/machines/Levers.shtml </li></ul><ul><li>http://www.mikids.com/Smachines.htm </li></ul><ul><li>http://dictionary.reference.com/browse/wedges </li></ul><ul><li>http://www.madsci.org/posts/archives/2002-04/1018042569.Sh.r.html </li></ul><ul><li>http://www.northallegheny.org/schools/mms/TSA%202006/TSA2007/Wheel%20and%20Axle.html </li></ul><ul><li>http://www.madsci.org/posts/archives/2003-05/1053546804.Sh.r.html </li></ul><ul><li>http://www.mikids.com/SMachinesWheels.htm </li></ul><ul><li>http://discover.edventures.com/images/termlib/f/first_class_lever/support.gif </li></ul><ul><li>http://discover.edventures.com/images/termlib/t/third_class_lever/support.gif </li></ul><ul><li>http://discover.edventures.com/images/termlib/s/second_class_lever/support.gif </li></ul>

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