Explain that a force is a push or a pull, and predict whether balanced forces (no change in motion) or unbalanced forces (a change in motion) are acting in a given scenario.
A force is simply a push or a pull. Every time something starts moving, stops moving, speeds up, slows down, or changes direction, a force is behind it. Forces can come from a hand, from wind, from gravity, or from one object bumping another.
Sometimes two or more forces act on the same object at once. If the forces are equal and pushing or pulling in opposite directions, they are called balanced forces, and the object does not change its motion at all. If the forces are not equal, they are unbalanced forces, and the object speeds up, slows down, or changes direction.
Mastery looks like: They can label a real scenario as balanced or unbalanced forces and correctly predict what happens to the motion.
Common stumbles: Assuming "balanced" means no forces are present at all, rather than equal forces canceling out.