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Azza Zidan Experimental Language School

Azza Zidan Experimental Language School. Science Department. Senior Teacher . Nosa Essa. Present. Science & You. Science Department. Second Term. PRIMARY SIX. Unit One. Force And Motion. LESSON ONE. Types of levers. Which of the two ways saves a lot of time and effort ??.

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Azza Zidan Experimental Language School

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  1. AzzaZidan Experimental Language School Science Department Senior Teacher \ NosaEssa Present Science & You

  2. Science Department Second Term PRIMARY SIX Unit One Force And Motion

  3. LESSON ONE Types of levers

  4. Which of the two ways saves a lot of time and effort ??

  5. Crowbar • In the past, • man invented many simple machines to help him to perform the heavy tasks easily

  6. The most common simple machines are • Levers

  7. Do you know that • Levers were first described in 260 B.C • By the • Greek scientist “Archimedes”

  8. What is the meaning of levers ???

  9. Nutcracker Manual broom Seesaw 1-Are all these machines ( levers) similar in shape and size ??? Soda water opener Pump Wheelbarrow

  10. Nutcracker Manual broom Seesaw 2-Are all these machines ( levers) consist Of a rigid bar??? Soda water opener Pump Wheelbarrow

  11. Nutcracker Manual broom Seesaw 3-Are all these machines ( levers) made Of the same material??? Soda water opener Pump Wheelbarrow

  12. Nutcracker Manual broom Seesaw 4-Are all these machines ( levers) are used to move An object??? Soda water opener Pump Wheelbarrow

  13. Manual broom Nutcracker Seesaw 5-Is there a person affects On each machine by a force??? Soda water opener Pump Wheelbarrow

  14. Manual broom Seesaw Nutcracker 6-Is there a fixed point , where each machine ( levers ) rotate on ??? Soda water opener Pump Wheelbarrow

  15. What does the lever consist of ??? • Any lever consists of : • 1-"Resistance"(R): • [resulted from • the weight of the body that we want to move]

  16. What does the lever consist of ??? • Any lever consists of : • 2-“Force"(F): • [exerted by a person ]

  17. What does the lever consist of ??? • Any lever consists of : • 3-“Fulcrum"(O): • [ is a fixed point of a rigid bar]

  18. What is the meaning of levers ??? So that • The lever is: • a rigid bar that rotates around a fixed point called the fulcrum and is affected by force and resistance.

  19. Importance of levers : • Levers are very important in our daily life.(G.R) • Because, they are used in:

  20. 1- Increasing force : Soda water opener Crowbar Wheelbarrow Nutcracker • Some levers conserve (save) effort .(G.R) Because in some levers, we use a small force to make a great effort [as moving a heavy load].

  21. 2- Increasing distance : • Some levers allow exerting a force for a small distanceto move an object for a longer distance. Ex:A manual broom

  22. The manual broom is considered as • an increasing distance lever. (G.R) Because, • your hand moves a small distance at the upper part of the broom, while its lower part moves a longer distance.

  23. 3-Increasing speed : • Some levers increase the speed of objects that affect on them . • Ex:The hockey bat .

  24. 4-Moving the force from one place to another : • Ex:Themanual broom In the manual broom, the force of your hand moves from the upper part to the lowerpart of the broom to collect the garbage without bending.

  25. 5- Accuracy in performance : • Some levers are used to pick up (capture)very small objects . Ex:The tweezers.

  26. 6- Avoid dangers : • Some levers are used to pick up hot , cold and poisonous materials . Ex:The coal holder. The ice holder.

  27. Exercises A)Write the scientific term : • 1-The first scientist who described the lever . [……………] • 2-A fixed point of a rigid bar . [……………] • 3-The rigid bar rotates around a fixed point and is affected by a force and resistance . [……………] • 4-A lever allows saving the effort . [……………] • 5-A lever allows increasing the distance . [……………]

  28. Exercises A)Write the scientific term : • 6-A lever allows increasing the speed . [……………] • 7-A lever moves the force from one place to another [……………] • 8-A lever used to pick up very small objects . [……………] • 9-A lever protects our hand from heat . [……………] • 10-A lever protects our hand from cold . [……………]

  29. Types of levers First- class levers Second- class levers Third- class levers

  30. First – class levers • 2-The backbone F ← O → R • 1- The fulcrum is between force • and resistance . • 2- It is the most popular type of levers in our daily life. • 3- Each of Scissors , pliers, pincerand nail • clipper are composed of two first levers.

  31. Second – class levers O ← R → F • The resistance is between force and fulcrum .

  32. Third – class levers O ← F → R • Force is between fulcrum and resistance

  33. Comparison between the three types of levers :

  34. Exercises • Classify the following tools according to the type of lever:

  35. AzzaZidan Experimental Language School Done by Senior Teacher \ NosaEssa Under supervision of \ Dr. NagatRabee

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