3rd Grade Science Lesson

Push, Pull, and Stay Still: Balanced & Unbalanced Forces

Shared by A STEM Educator

3rd Grade5e-learning-cycle3-PS2-1, 3-PS2-245 min

Learning Objective

Students will be able to distinguish between balanced and unbalanced forces, predict whether an object will remain stationary or change its motion, and identify the direction of motion when forces are unequal.

Lesson Overview

Students explore how balanced and unbalanced forces affect the motion of objects using the real-world context of pushing a heavy stalled parade float across concrete. They categorize force scenarios, measure pushes with spring scales, and predict motion outcomes.

Materials

Two printed tug-of-war photos (rope stationary vs. rope moving)
Spring scales (one per group)
Small wooden blocks or toy cars
Smooth surface (desk) and rough surface (carpet square)
Sticky notes (two colors)
Force arrow scenario cards (printed)
Rulers
Student science notebooks
Whiteboard markers and mini whiteboards
Printed Four-Quadrant note sheets

Scaffolded Task Progression

1Task 1

Look at the two tug-of-war photos below.

[ Interactive graph / diagram — available in the full lesson ]

In Photo 1, both teams pull with equal strength and the rope does not move. In Photo 2, Team A pulls harder and the rope moves toward Team A.

Question: What is the one thing that is different between Photo 1 and Photo 2 that causes the rope to move?

2Task 2

Two-Side Push Lab — Data Table

Your group pushed a block from both sides using a spring scale. Fill in the table below with your results, then draw force arrows for each trial.

Trial	Left Force	Right Force	Did it move?	Which direction?
1	$2$ N	$2$ N	___	___
2	$2$ N	$1$ N	___	___
3	$3$ N	$0$ N	___	___

After filling in your table, answer: What pattern do you notice about when the block moves vs. when it stays still?

Unlock the full lesson

See all 7 scaffolded tasks, the full answer key, warm-up, exit slip, and a print-ready version — free to start.

Create a free account

Already have an account? Sign in

Make it your own

Like this lesson but want to tweak it?

Make an editable copy and adjust the tasks, warm-up, and answer key to fit your class — no need to start from scratch.

Generate a new lesson