MS-PS2-1: Apply Newton’s third law to design a solution to a problem involving the motion of two colliding objects.

Clarification Statement: Examples of practical problems could include the impact of collisions between two cars, between a car and stationary objects, and between a meteor and a space vehicle.

MS-ETS1-1: Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

MS-ETS1-2: Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

By the end of grade 8.For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first but in the opposite direction (Newton’s third law). 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. Forces on an object can also change its shape or orientation. All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame.

Evidence Statements

MS-PS2-1

1. Using scientific knowledge to generate design solutions

   1. Given a problem to solve involving a collision of two objects, students design a solution (e.g., an object, tool, process, or system). In their designs, students identify and describe:

      1. The components within the system that are involved in the collision.

      2. The force that will be exerted by the first object on the second object.

      3. How Newton’s third law will be applied to design the solution to the problem.

      4. The technologies (i.e., any human-made material or device) that will be used in the solution.

2. Describing criteria and constraints, including quantification when appropriate

   1. Students describe the given criteria and constraints, including how they will be taken into account when designing the solution.

      1. Students describe how the criteria are appropriate to solve the given problem.

      2. Students describe the constraints, which may include:

         1. Cost.

         2. Mass and speed of objects.

         3. Time.

         4. Materials.

3. Evaluating potential solutions

   1. Students use their knowledge of Newton’s third law to systematically determine how well the design solution meets the criteria and constraints.

   2. Students identify the value of the device for society.

   3. Students determine how the choice of technologies that are used in the design is affected by the constraints of the problem and the limits of technological advances.