Unit Plan 2 (Grade 3 Science): Force Basics

Focus: Investigate pushes and pulls and how they affect an object’s motion (start, stop, speed, direction).

Grade Level: 3

Subject Area: Science (Physical Science • Inquiry/Engineering Prep)

Total Unit Duration: 5 sessions (one week), 45–60 minutes per session

I. Introduction

In this unit, students build an intuitive foundation for force as a push or pull that can change how objects move. Through hands-on stations, simple measurements, and class discussions, they explore how stronger or weaker forces affect motion and how balanced and unbalanced forces relate to starting, stopping, and changing direction. Students begin to design and interpret simple investigations that connect their everyday experiences (kicking balls, sliding books, pushing chairs) to science language about forces.

Essential Questions

• What is a force, and how are pushes and pulls part of our everyday lives?
• How do stronger or weaker pushes and pulls change an object’s speed or direction?
• What is the difference between balanced and unbalanced forces, and how do they affect motion?
• How can we plan and conduct an investigation to show the effects of forces on motion?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Describe forces as pushes or pulls and identify examples in everyday situations.
2. Plan and conduct simple investigations where they change force size or direction and observe effects on motion.
3. Use observations to distinguish between situations with balanced forces (no change in motion) and unbalanced forces (change in motion).
4. Record data (tables, tallies, sketches) about how objects start, stop, speed up, slow down, or change direction.
5. Explain their investigation results in clear student language, linking evidence to claims about how forces affect motion.

Standards Alignment — 3rd Grade (NGSS-Aligned)

• 3-PS2-1 — Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.
  • Example: Test how different sized pushes affect how far or fast a toy car moves, and compare situations where forces are equal vs. not equal.

Success Criteria — Student Language

• I can tell the difference between a push and a pull and give real-life examples.
• I can plan and carry out a simple test to see what happens when I change how hard I push or pull an object.
• I can use my observations to say when forces are balanced (no change in motion) and unbalanced (motion changes).
• I can use data (numbers, tallies, or simple graphs) to show how an object’s motion changed.
• I can explain my thinking: “Because I saw this, I know the forces on the object were balanced/unbalanced.”