`Simple MachinesSusan Frazier                  Fort Dearborn                               9025 Throop Street                               Chicago, Ill.                               312-881-5180Objectives:Adaptable to grades 1 to 12The student will be able to:            1) define and give examples of "work" and "machine"      2) identify simple machines (inclined plane, screw, lever,         wheel and axle, wedge, and pulley)      3) classify simple and compound machines       4) name body parts that can be used as simple machinesMaterials: paint can, book, spring scale, meter stick, string, milk carton, several pulleys, toy car--weighted, three boards-same length, three boards-different length, long poleStrategy:                            Work and Simple Machines     Have several students attempt to open an empty paint can with their hands or attempt to move a heavy desk.  Have the students determine that although   force was used, the objects did not move a distance and there was no motion; thus, no work was done since work is equal to force times distance.      Then have a student open the paint can by using something to pry off the top of the can.  Explain that the object was used as a lever, one kind of simple machine, and that a machine is something that makes work easier to do.Also help the students discover that two or more simple machines can be used together to make compound machines.                                  Activity-Lever     Tie a book to one end of a meter stick.  Use a milk carton weighted with dirt or sand as the fulcrum, the point on which the stick rests or turns.  Set the fulcrum at the 15 cm mark.  On a chart, record where the fulcrum was set, the load arm length, and the force arm length.  Use the end of the spring scale to pull down the end of the meter stick and record the force shown on the scale. Repeat the steps above for 20 cm, 25 cm, 30 cm, and 35 cm.  Discuss the placement of the fulcrum in relation to the placement of the load and the amount of force needed to lift the load.  Have the children discover the direction the load moves and the direction of the force.                                  Activity-Pulley      Use a horizontal bar to attach a fixed pulley, a combination of a fixed pulley and movable pulley, and a combination of several fixed and movable pulleys.  Lift a load attached to a spring scale straight up in the air.   Next, lift a load attached to a fixed pulley, then a fixed and movable pulley, and finally, a multiple pulley combination.  Record the force needed for each.  Discuss which one required the most force to lift the load.  Which one required the least force.  Determine the direction of the load and the force for each kind of pulley.  Determine the relationship of the number of pulleys used and the amount of force needed to lift the load.                        Activity-Inclined Plane, Screw, Wedge     Discuss the relationship of the inclined plane, the wedge, and the screw.  Next, attach a car to a spring scale and lift up in the air.  Then, pull a car attached to the spring scale up three different inclines--the same length, butdifferent heights.  Pull a car up three different inclines with different lengths but raised to the same height.  Record the force for each.  Notice the relationship of the length and height of the inclined plane and the amount of force used.                             Activity-Wheel and Axle      One person holds a stick with one hand while a partner places her/his hands on either side of the person holding the stick.  The partner tries to   turn the stick "wheel" while the person holding the middle tries to keep thestick from turning.  Next, the partner moves her/his hands farther apart and tries to turn the wheel.  The partner continues to move the hands apart until the wheel turns easily.  The person's arm acts as the axle, and the pole is the wheel.  The children determine the relationship between the size of the wheel and the amount of force needed to turn the wheel.                              Activity-CulminatingName body parts used as machines.  Rapidly classify machines placed in a brownbag.  Use as a team game.`