During this CELL, students will perform several investigations focused on work and simple machines. By completing multiple trials and investigating the effect of different variables, students will begin to draw conclusions concerning the relationship between work, force, and distance. Students will use the formula Work = Force x distance to calculate work and to define and explore the relationship between its components: the force applied to a load and the distance over which the force is applied.

Through investigations centered on simple machines such as the pulley, the lever, and the inclined plane, students will discover the advantages of using simple machines. Students will find that the single fixed pulley offers an advantage by reversing the direction of the applied force. The lever and the inclined plane, however, offer a different type of advantage by altering the force and distance. As the applied force decreases, the distance over which that force is applied must increase. Likewise, the inverse is also true. As the distance over which the force is applied decreases, the applied force must increase.

Through these applications and explorations, students will begin to conceptualize work and the factors that affect it. This Core Experience will challenge students to apply these ideas to everyday situations, building continuity between classroom investigations and daily applications.

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Investigation 1: Exploring Forces

In Investigation One, students will explore the concept of force as the effort needed to lift or move a load. Students will investigate the force exerted by solids, liquids, and gases and will vary the mass of the load in order to determine the relationship between mass and force exerted to lift a load.

Investigation 1: Teacher’s Video (4:29)

 Investigation 1: Student’s Video (13:28)

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Investigation 2: Understanding Work      

Investigation Two guides students to explore the concept of work. Students perform several trials in which they vary the mass of the load and the distance each load is lifted, discovering the relationship between force, distance, and work. To further investigate this relationship, students use the formula Work = Force x distance to calculate work.

Investigation 2: Teacher’s Video (10:02)

Investigation 2: Student’s Video (13:55)

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Investigation 3: Simple Machines: The Pulley      

During Investigation Three, students will begin their exploration of simple machines by investigating the pulley. Students will calculate and compare the work done when performing a task with and without a pulley, varying the mass of the load and the distance the load is lifted. This investigation guides students toward concluding that the pulley makes work feel easier by changing the direction force is applied to a load, even though the amount of work done remains the same.

Investigation 3: Teacher’s Video (11:19)

Investigation 3: Student’s Video (22:00)

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Investigation 4: Simple Machines: The Lever

Investigation Four introduces students to a second simple machine, the lever. Students will explore the use of the lever by varying the location on the lever at which the effort is applied and by varying the position of the fulcrum. Through this investigation, students will discover that by varying the location of the effort or by varying the location of the fulcrum, the force required to lift the load changes. However, students will also find that when using a lever, a change in the force required is accompanied by an inverse change in the distance over which the force is exerted so that the work done to perform a certain task does not increase or decrease.

Investigation 4: Teacher’s Video (10:44)

 Investigation 4: Student’s Video, Trials 1-4 (20:47)

 Investigation 4: Student’s Video, Trials 6-9 (10:31)

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Investigation 5: Simple Machines: The Inclined Plane

In Investigation Five, students will be introduced to a third simple machine, the inclined plane. Students will explore the relationship between the effort needed to move a load over inclined planes that are the same in height but differ in their steepness. By performing several investigations focused on this relationship, students will discover that, because the inclined planes are the same height, as the steepness of the inclined plane increases, the length over which an object moves decreases, and the force to move a load increases. In addition, students will find that when comparing the work done with inclined planes that have the same height but a different steepness the work remains the same due to an inverse relationship between effort to move the load and the distance over which the load is moved.

Investigation 5: Teacher’s Video (10:56)

 Investigation 5: Student’s Video (19:33)

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Investigation 6: Performance Assessment

Investigation Six consists of a performance assessment designed to evaluate students’ understanding of the science concepts addressed in the first five Investigations of the Core Experience. During this exploration, students will design and implement the use of a simple machine.

Investigation 6: Performance Assessment – Teachers Only (4:56)