Science
Strand IV
Use Scientific Knowledge from the Physical Sciences in Real-World Contexts

 

Science/Strand IV
Content Standard 3
All students will describe how things around us move and explain why things move as they do; demonstrate and explain how we control the motions of objects; and relate motion to energy and energy conversions. (Motion of Objects)

 

Science/Strand IV/Content Standard 3
Middle School

 

Science/Strand IV/Content Standard 3/Middle School
Benchmark 5
Design strategies for moving objects by application of forces, including the use of simple machines.

Benchmark Clarification

A simple machine is a device, such as a lever, pulley, screw, etc., for controlling the application of forces. For example, a lever can transform a small downward force into a large upward force. A small twisting force on a screw can transform into a large penetrating force into a piece of wood.

The only disadvantage for simple machines is that an external force must be applied over a greater distance in order to move an object a small distance. With a lever, a force must push down on the lever at a longer distance to lift an object a smaller distance. A screw must be twisted many times in order to move it into a piece of wood a shorter distance.

Students will:

Design strategies for moving objects using simple machines (e.g., moving furniture from a second story)

Key Concept / Real World Context / Instructional Example / Assessment Example / Resources

 

Science/Strand IV/Content Standard 3/Middle School/Benchmark 5
Key Concept
Types of simple machines:

  • lever
  • pulley
  • screw
  • inclined plane
  • wedge
  • wheel and axle
  • gear

Other Key Concepts:

  • direction change
  • force advantage
  • speed and distance advantage

 

Science/Strand IV/Content Standard 3/Middle School/Benchmark 5
Real World Context
Objects being moved by using simple machines:

  • wagons on inclined planes
  • heavy objects moved by levers
  • see-saw

 

Science/Strand IV/Content Standard 3/Middle School/Benchmark 5
Instructional Example

Benchmark Question: How can we control the motions of objects?

Focus Question: How can we use simple machines to make work seem easier?

Students will work in small groups to complete the following activities:

Students will pound a large nail into a piece of wood. The teacher should make sure they leave at least three cm of the top of the nail above the board. Students will try to remove the nail with their fingers and then with the claw of a hammer. Students will discuss the difference in effort needed to remove the nail with their fingers and with the hammer claw. How and why did the hammer make the job easier?

Next, students will screw a screw into a piece of wood. Students will try to unscrew the screw with their hand and then with a screwdriver. Students will discuss the difference in effort needed to remove the screw with their fingers and with the screwdriver. How and why did the screwdriver make the job easier?

Caution: Make sure that all students wear safety glasses during this activity.

Constructing: (SCI.I.1.MS.1), (SCI.I.1.MS.4).

Reflecting: (SCI.II.1.MS.3).

 

Science/Strand IV/Content Standard 3/Middle School/Benchmark 5
Assessment Example

The following assessment can be used at the end of the pulley section of the simple machine unit.

The teacher will read the following scenario to the class:

A man has fallen into a deep hole with slippery sides. He has tried but cannot climb out. Before falling into the hole, he left a long rope, two fixed pulleys, and two movable pulleys on the ground above. Traveling with the man was his small son. The man can shout directions to his son but his son cannot pull him out or run for help. There are no ladders or anyone else to help. The only way out is to use the pulleys and rope.

Each student will write out directions that explain to the son what to do in order to get the man out of the hole and will draw a picture of the procedure to get the man out of the hole.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Completeness of directions

Writes few directions with no details.

Writes most steps of the directions in correct order using pulleys and including a few details.

Writes step-by-step directions in correct order using pulleys and including some details.

Writes step-by-step directions in correct order using pulleys and including many details.

Correctness of diagram

Draws a partial diagram with no labels.

Draws a diagram with most information correct and a few labels.

Draws a diagram that includes the proper set-up and use of pulleys with some labels.

Draws a diagram that includes the proper set-up and use of pulleys with all labels.

 

Science/Strand IV/Content Standard 3/Middle School/Benchmark 5
Resources

Webliography.
http://mtn.merit.edu/mcf/SCI.IV.3.MS.5.html

Brick Layers. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl

Friction/Simple Machines. Bill Nye Video. Disney Educational (800/295-5010).

Machine Shop. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl

Momentum/Gravity. Bill Nye Video. Disney Educational (800/295-5010).

OPERATION PHYSICS.