Science.6.7.C

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The student is expected to identify simultaneous force pairs that are equal in magnitude and opposite in direction that result from the interactions between objects using Newton's Third Law of Motion.
1666 TEKS header image

Knowledge and Skills Statement

Force, motion, and energy. The student knows the nature of forces and their role in systems that experience stability or change.

The further explanation is designed to be a resource for educators that helps them better understand the topic their students are learning. Further explanations may be written at a more complex level than would be expected for students at the grade level.

If object A and object B interact (collide), then object A will exert a force on object B and object B will exert an opposing force on object A, but in the opposite direction. 

A cart with a person on it pulls a rope that is also being pulled in the opposite direction by another person on a different cart. The carts are moving toward each other. Each cart is labeled with Force AB and arrows pointing toward each other to represent equal and opposite forces.
Image Source: File:Newton-reciproka.svg - Wikimedia Commons

For example, the force of the weight of an object on a table creates the simultaneous force of the table pushing up on the object; this is called the normal force.  When a collision occurs between two objects, they each simultaneously exert an equal and opposite force on each other.

One common misconception is that Newton's third law describes a cause-and-effect relationship (action leads to reaction). Another misconception is that the force pair acts on the same object. The force pair describes the forces that occur simultaneously as a result of an interaction between two objects.
 

Glossary terms and definitions are consistent across kindergarten through high school in the TEKS Guide. The definitions are intended to give educators a common understanding of the terms regardless of what grade level they teach. Glossary definitions are not intended for use with students.

numerical size of a quantity

regularly interacting or interdependent group of items forming a unified whole

Research

Bobrowsky, Matt. “SCIENCE 101: Q: What’s Wrong With ‘For Every Action, There Is an Equal and Opposite Reaction’?” Science and Children 56, no. 7 (2019): 69–73. https://www.jstor.org/stable/26901433.

Summary: This article details Newton's Third Law, explaining that forces come in pairs. Multiple examples are provided to illustrate the concept, and common misconceptions are addressed through simple activities.