Introduction to Forces: Pushes and Pulls

Active learning works well for this topic because students need to physically feel and see the effects of forces to move beyond abstract ideas. Engaging in hands-on tasks helps them connect push and pull actions with real-world motion changes, building intuitive understanding before formalizing concepts like net force and balanced forces.

• 5th Year
• Principles of the Physical World: Senior Cycle Physics
• 4 activities
• 20 min–45 min

Learning Objectives

1. Identify and classify everyday examples as either a push or a pull force.
2. Explain how balanced forces acting on an object result in no net change in motion.
3. Predict the direction of motion of an object when subjected to unbalanced forces.
4. Compare the effects of different magnitudes of push and pull forces on an object's motion.
5. Analyze simple force diagrams to determine the net force acting on an object.

Experiential Learning

⏱ 30 min·Pairs

Tug-of-War Net Force

Pairs mark a line on the floor and tug a rope with equal or unequal forces. Students predict if the center cloth moves based on balance, then measure displacement after 10 seconds. Discuss net force direction in a class share-out.

Prepare & details

Differentiate between a push and a pull force with examples.

Facilitation Tip: During Tug-of-War Net Force, have students record force values and arrows on whiteboards before discussing net force outcomes to make thinking visible.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 45 min·Small Groups

Toy Car Push-Pull Relay

Small groups line up toy cars and take turns applying measured pushes or pulls with rulers. Record speed changes on a data table, then draw force arrows to show net force. Compare predictions to observations.

Prepare & details

Explain how multiple forces acting on an object can result in no change in motion.

Facilitation Tip: For Toy Car Push-Pull Relay, provide varied surfaces (e.g., carpet, tile) to let students feel differences in force application and motion.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 20 min·Whole Class

Balanced Forces Balance

Whole class observes hanging weights on a balance scale, adding equal masses to sides. Students predict equilibrium points, adjust forces, and note no motion. Extend to predict unbalanced outcomes.

Prepare & details

Predict the direction of motion when unbalanced forces act on an object.

Facilitation Tip: When using Balanced Forces Balance, ask students to test different mass combinations to determine when forces balance, linking to the concept of equilibrium.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Experiential Learning

⏱ 25 min·Individual

String Pull Predictions

Individuals tie strings to objects and predict motion from multiple pull directions sketched on paper. Test pulls gently, observe paths, and revise arrow diagrams. Share one insight with the class.

Prepare & details

Differentiate between a push and a pull force with examples.

Facilitation Tip: In String Pull Predictions, require students to sketch predicted force diagrams before testing to confront initial misconceptions about force direction.

Setup: Varies; may include outdoor space, lab, or community setting

Materials: Experience setup materials, Reflection journal with prompts, Observation worksheet, Connection-to-content framework

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Teaching This Topic

Teach this topic by starting with concrete examples students can relate to, then move to guided inquiry where they manipulate variables to observe outcomes. Avoid introducing inertia too early; focus on observable changes in motion from pushes and pulls. Research shows that students grasp net force better when they experience unequal forces firsthand and see the gradual effects of small unbalanced forces.

What to Expect

Successful learning looks like students accurately describing forces as pushes or pulls, predicting motion based on net force, and explaining balanced versus unbalanced forces using examples from the activities. They should confidently draw force diagrams and justify their reasoning with evidence from observations.

Watch Out for These Misconceptions

Common Misconception

During Toy Car Push-Pull Relay, watch for students assuming the car needs continuous pushing to keep moving.

What to Teach Instead

Pause the relay and ask students to glide the car on a smooth surface after one push, prompting them to observe that motion continues without additional force, linking to the idea of inertia.

Common Misconception

During Tug-of-War Net Force, watch for students believing pushes and pulls are fundamentally different forces.

What to Teach Instead

Have teams draw vector arrows on the ground with tape, labeling each arrow as push or pull, then compare directions to show they are opposite contact forces.

Common Misconception

During String Pull Predictions, watch for students expecting every force to cause an immediate large change in motion.

What to Teach Instead

Ask students to predict and test how the car’s speed changes with increasing string pull length, then graph their data to reveal proportional relationships between force and acceleration.

Assessment Ideas

Exit Ticket

After Tug-of-War Net Force, provide a scenario where two students pull a rope with different strengths. Ask students to: 1. Draw force arrows showing the net force direction. 2. Circle whether the forces are balanced or unbalanced. 3. Predict which way the rope will move and why.

Quick Check

During Balanced Forces Balance, show a seesaw diagram with unequal masses. Ask students to write: 1. The direction of the net force. 2. Whether the forces are balanced or unbalanced. 3. What will happen to the seesaw’s motion.

Discussion Prompt

After Toy Car Push-Pull Relay, pose: 'If you pushed a heavy box and it didn’t move, what must be true about the forces? Use the terms net force, balanced forces, and friction to explain.' Have students discuss in pairs before sharing with the class.

Extensions & Scaffolding

• Challenge students to design a system where a small unbalanced force causes a large object to move, using limited materials.
• For students struggling with net force, provide pre-drawn force diagrams with missing arrows and ask them to complete and label them.
• Deeper exploration: Have students research and present on how forces are used in simple machines, connecting pushes and pulls to mechanical advantage.

Key Vocabulary

Force	A push or a pull that can cause an object to change its motion, shape, or direction.
Push	A force that moves an object away from the source of the force.
Pull	A force that moves an object toward the source of the force.
Net Force	The overall force acting on an object when all individual forces are combined. It determines the object's acceleration.
Balanced Forces	When two or more forces acting on an object are equal in magnitude and opposite in direction, resulting in no change in the object's motion.
Unbalanced Forces	When forces acting on an object are not equal in magnitude or opposite in direction, causing a change in the object's motion (acceleration).