Torque

Larry L. Smart                 Helen Hefferan Elem.School
5525 W. Quincy St.             4409 W. Wilcox St.
Chicago IL 60644               Chicago IL 60624
(312)378-9159                  (312)534-6129

Objectives:

This assignment will be for 6th grade students. The main objective of this mini-
teach is to show the difference between Work and Torque, in relationship to 
Force and Distance. 

Materials Needed:

   1. A Jensen balance bar with ten 50 gram weights. 
   2. A Torque bar with a 500g weight.
   3. A wooden wheel with four nuts and bolts drilled in it.

Strategy:

   1. The students are given the weight and distance on the left side of the 
      balance bar and asked where to place another weight in order to balance 
      the bar. 
   2. Give the student the torque bar and a weight.  The teacher moves the 
      weights to different positions on the bar.  Record the student's 
      observation. 
   3. Have some students use a small wrench to loosen 2 bolts and other students 
      use a large wrench to loosen 2 bolts.  Record the observations.  Discuss 
      the ratio between amount of force and the length of the wrench.  (The 
      longer the wrench, the less force required to loosen the bolts.) 
                                   
Performance Assessment:

  Assessment will be based on the following: 
   1. The teacher will put a weight on the balance bar at a specific location 
      and give the student a weight.  The student will be asked to balance the 
      bar by choosing the appropriate location on the bar. 
   2. Torque worksheet with the formula, (T = D x F). 
   3. The student will explain why the larger wrench loosens the nut with less 
      force than the smaller wrench.

Conclusions:
  
   1. The torque on both sides of a Jensen Arm, when the bar is balanced, will 
      be equal. 
   2. The bar will require more force in order to hold it horizontally as the 
      weight is moved away from the handle. (It will feel "heavier", but it is 
      the SAME MASS, only in a different location.  It requires MORE FORCE, but 
      is no heavier.) 
   3. The larger wrench will remove the nuts with less force than the smaller 
      wrench.  (D x f = d x F)  (The large wrench, a BIG DISTANCE times a small 
      force is equal to a small distance times a BIG FORCE, the small wrench.) 
   4. The difference between torque and work is the concept of rotation.  Torque 
      is work (distance times force) which causes rotation.