Shaduf Revisited

Reviewing the Lever

Review the features of the shaduf lever:

If the shaduf is balanced perfectly, the weight of the water x the left arm distance is equal to the counterweight x the right arm distance.  Students can create a data table to collect observations based on different placements of the fulcrum. In the chart below the fulcrum can be moved to create an imbalance.  The imbalance should always be positive on the right side of the lever so that the counterweight can lift the bucket.

TABLE 1

----------------------------

WATER        LEFT ARM     LEFT       COUNTER-   RIGHT ARM    RIGHT

WEIGHT      DISTANCE     F x D       WEIGHT        DISTANCE       F x D       IMBALANCE

------------      ---------------     --------     -----------        --------------         -------      ------------------

Finding the optimal imbalance point is one aspect of engineering. 

Here are some references if you need some support on the concept of levers.

• A basic review of levers: http://www.enchantedlearning.com/physics/machines/Levers.shtml

• Learning activities related to levers: http://www.technologystudent.com/forcmom/lever1.htm

• Engineering Toolbox: Formulas and mathematics. http://www.engineeringtoolbox.com/levers-d_1304.html

• Powerpoint Presentation on levers  http://www.authorstream.com/Presentation/aSGuest37927-322983-work-machines-ppt-entertainment-powerpoint/