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PS2: Motion and Stability: Forces and Interactions

Core Idea

PS2:  Motion and Stability: Forces and Interactions

PS2.A: Forces and Motion
PS2.B: Types of Interactions
PS2.C: Stability and Instability in Physical Systems

Content aligned with middle school PS2

Content aligned with high school PS2


In middle school, students develop an understanding of the disciplinary core ideas in the physical science domain. The middle school performance expectations build on the elementary performance expectations and allow students to explain concepts that are important not only to physical science, but also to life science and the earth and space sciences. In PS2: Motion and Stability: Forces and Interactions, performance expectations are designed for students to create an understanding of how different types of forces interact to create motion. Students should demonstrate an understanding of how action-reaction, gravitational, electrical, and magnetic forces cause motion.


In high school, students continue to develop and refine their understanding of physical science concepts. The high school performance expectations are meant to expand on the middle school performance expectations. The high school performance expectations cover fundamental concepts of chemistry and physics, while leaving room for more expanded and in-depth study in upper level high school courses. As in middle school, physical sciences concepts are also important for understanding life and Earth and space sciences. Performance expectations in high school PS2: Motion and Stability: Forces and Interactions call for students to apply knowledge in order to predict interactions between objects and within systems. More advanced concepts in this core idea include the relationships between force and mass and how these relate to acceleration, momentum, and gravitation.


PS2: Motion and Stability: Forces and Interactions

Middle School

MS-PS2-2 Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object.

MS-PS2-3 Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.

MS-PS2-4 Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects.

MS-PS2-5 Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other even though the objects are not in contact.


PS2: Motion and Stability: Forces and Interactions

High School

HS-PS2-1 Analyze data to support the claim that Newton’s second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration.

HS-PS2-4 Use mathematical representations of Newton’s Law of Gravitation and Coulomb’s Law to describe and predict the gravitational and electrostatic forces between objects.

Special Feature Type:

Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.