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
Elementary

 

Science/Strand IV/Content Standard 3/Elementary
Benchmark 2
Explain how forces (pushes or pulls) are needed to speed up, slow down, stop, or change the direction of a moving object.

Benchmark Clarification

An object moves in a straight line and at a constant speed as long as balanced forces act on it. When a force acts on an object, it can speed up the object’s motion, slow it down, or change its direction. The greater the force acting on the object, the greater the change in the object’s speed and/or direction. Friction is one force that makes an object decrease speed, when no other pushes or pulls (forces) appear to be acting upon it.

Students will:

  • Demonstrate and describe the motion of objects
  • Investigate the forces that make an object move

Descriptions should include:

  • Friction — a force that works against motion
  • Gravity — a force that makes things fall toward the center of the Earth
  • Other pushes or pulls — forces exerted by people and machines

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

 

Science/Strand IV/Content Standard 3/Elementary/Benchmark 2
Key Concept
Changes in motion:

  • speeding up
  • slowing down
  • turning

Common forces:

  • push
  • pull
  • friction
  • gravity

Size of change is related to strength of push or pull

 

Science/Strand IV/Content Standard 3/Elementary/Benchmark 2
Real World Context

  • playing ball
  • moving chairs
  • sliding objects

 

Science/Strand IV/Content Standard 3/Elementary/Benchmark 2
Instructional Example

Benchmark Question: What forces are needed to impact the motion of a moving object?

Focus Question: Why do things move as they do?

Students in small groups will brainstorm everyday situations (i.e., swinging a baseball bat, pushing a merry-go-round, pedaling a bike) in which forces act upon an object to change its speed or direction. They will draw diagrams that include labels and arrows to describe the speed and direction of motion. They will present their diagrams to the entire class.

Small groups will experiment with forces needed to push or pull an object. Each group will choose a vehicle (wagon, car, truck) and design a course that contains a variety of surfaces (grass, sand, and concrete) and a variety of terrains (hills, curves, flat surfaces). Students will measure the distance around the course, the time it takes to complete the course, and record their data in the table given below:

 

Distance

Time

Observation

Pull

 

 

 

Push

 

 

 

Push & Pull

 

 

 

Students will navigate the course three times. First, they will push the object. Second, they will pull the object. Third, they will use a combination of pushes and pulls. Students will move the object as far as they can, measure the distance, and record the measurements in their data table. Students will make written observations in their science journals of their difficulties navigating the course.

Constructing: (SCI.I.1.E.1), (SCI.I.1.E.4), (SCI.I.1.E.5), (SCI.I.1.E.6).

Reflecting: (SCI.II.1.E.1).

 

Science/Strand IV/Content Standard 3/Elementary/Benchmark 2
Assessment Example

Using the data from the Instructional Example, students will write answers to the following questions:

  1. Which surface required the most force? Why?
  2. Which force (push or pull) took less effort in the sand?
  3. If you were pulling a heavy load, which surface would you like to travel on? Why?
  4. Why are bowling alleys smooth and hard?

(Give students rubric before activity.)

Scoring Rubric

This is pass/fail. If the student answers three of the four questions correctly, then he or she passes:

  1. The answer to Question #1 reflects the need to include sand and more friction.
  2. The answer to Question #2 reflects the need to include pull.
  3. The answer to Question #3 reflects the need to include concrete as well as reduced friction and force.
  4. The answer to Question #4 reflects the need to include less force and very little friction

 

Science/Strand IV/Content Standard 3/Elementary/Benchmark 2
Resources

Webliography.
http://mtn.merit.edu/mcf/SCI.IV.3.E.2.html

Nankivell, Sally. Science Experiments with Force. Watts, 2000.

Wells, Robert. How Do You Lift A Lion? Whitman, 1996.