Grade 3 · Forces and Motion · Forces and Changing Motion
Make Motion Change
A force is an interaction that can change an object's motion or shape. Some forces require touching; others act across a distance.
Visual model
See how the ideas connect
Distinguish contact and non-contact forces
Connect force size to changes
Identify forces in daily life
Forces and Changing Motion
For students
Notice, predict, explain
Choose one part of the model. Predict how it connects to another part, then use the lesson evidence to explain your thinking.
For teachers
Pause for science talk
Show the model before the explanation. Ask “What do you notice?” and “What might change?” Then revisit student ideas after the worked example.
The big idea
Forces can start, stop, speed up, slow down, turn, or reshape objects
Contact forces include applied pushes, pulls, and friction. Non-contact forces such as gravity and magnetic force act without the objects touching.
Work it through
Change a rolling ball
- Step 1 A push starts a ball moving across the floor.
- Step 2 A stronger push usually produces a larger change in its speed than a gentle push.
- Step 3 Friction between the ball and floor slows the ball even when no one touches it again.
- Step 4 A sideways contact force changes the ball's direction, while gravity keeps pulling it toward Earth.