• The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion. (6-8)

• When two objects interact, each one exerts a force on the other that can cause energy to be transferred to or from the object. (6-8)

• Cause and effect relationships may be used to predict phenomena in natural systems. (6-8)

• Modeling in 6–8 builds on K–5 and progresses to developing, using and revising models to describe, test, and predict more abstract phenomena and design systems. (6-8)
  • Develop and use a model to describe phenomena. (6-8)

• 3-5: 4F/E1a. Changes in speed or direction of motion are caused by forces.
• 3-5: 4F/E1bc. The greater the force is, the greater the change in motion will be. The more massive an object is, the less effect a given force will have.
• 6-8: 4F/M3a. An unbalanced force acting on an object changes its speed or direction of motion, or both.

• 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

This lesson plan for Grades 6-8, with printable student guide, is a great supplement to the PhET simulation Forces and Motion.  The winner of a PhET "Gold Star", it was developed by an experienced teacher to provide explicit guidance for students as they use the simulation to investigate force interactions. We like it because it provides just the right amount of help to navigate the simulation, while also allowing students to construct their own meaning from the model.

• Physical Sciences K-8 Newton's Second Law & Net Force Unit