SC15.8.10

Science (2015) Grade(s): 8

Developing and Using Models

Systems and System Models

Students know:

Whenever two objects interact with each other, they exert forces upon each other.
These forces are called action and reaction forces; forces always come in pairs.
For every action, there is an equal and opposite reaction.
The size of the force on the first object equals the size of the force on the second object.
The direction of the force on the first object is opposite to the direction of the force on the second object.
The momentum of an object increases if either the mass or the speed of the object increases or if both increases.
The momentum of an object decreases if either the mass or the speed of the object decreases or if both decrease.

Students are able to:

Develop a model that demonstrates Newton's third law and identify the relevant components.
Describe the relationships between components of the model.
Use observations from the model to provide causal accounts for events and make predictions for events by constructing explanations.

Students understand that:

Newton's Third Law states that 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.