Little Lab Coats

Collisions Transfer Energy

Physical Science — Energy & Motion | Unit 1, Lesson 2 of 6

📚 Grade: 4th Grade⏱️ Duration: 45–60 minutes🔬 Subject: Physical Science — Energy & Motion

🚗💥

When moving objects collide, energy can transfer and change what moves next.

📋 NGSS Standard:
4-PS3-3 — Ask questions and predict outcomes about the changes in energy that occur when objects collide.

🎯 Learning Objective

Students will observe collisions and explain, with evidence, how energy can transfer from one object to another.

💡 The Big Idea

A moving object can transfer energy during a collision and cause another object’s motion to change.

🔬 The Science

Science Snapshot

Collisions redistribute energy across motion, sound, heat, and shape change.

What is happening?

During a collision, energy can transfer from one moving object to another. Some energy may also spread as sound, heat, or deformation, which is why the moving object does not always keep all of its original motion.

Why it works that way

The transfer depends on how fast the objects were moving, how much mass they had, and what the materials were like. Even a brief collision can strongly change motion because large forces act for a short time.

Look for this in the lesson

Students should use before-and-after observations to infer the energy transfer. That evidence is stronger than vague statements like “they hit each other.”

Ask while you read: Where did the energy go after the collision if the original object slowed down?

📦 Materials

🏠 Household Items to Gather

Two toy cars, marbles, or rolled balls
Flat surface or floor space
Tape for start lines
Worksheet and pencil

📋 Printables

Student worksheet page from this lesson

🧪 Investigation

Step 1 — Predict the collision (5 min)
Ask what might happen when one moving object hits a resting object.

Step 2 — Run a soft collision (10 min)
Gently roll one object into another and watch what both objects do.

Step 3 — Run a stronger collision (10 min)
Repeat with more starting speed and compare the change.

Step 4 — Record both objects (10 min)
Students note what happened to the moving object and the resting object after impact.

Step 5 — Explain the transfer (10 min)
Use evidence to describe how energy moved during the collision.

💬 Discussion Questions

What evidence shows that energy moved during the collision?A resting object started moving, or the moving object slowed, stopped, or changed direction.

Why compare a softer and stronger collision?It helps show how a bigger starting motion can lead to a bigger change.

Did only one object matter in this test?No. Both objects provide evidence after the collision.

🚀 Extensions

Extension: Set up a three-object line and watch how motion can move through more than one object in sequence.

👩‍🏫 Parent/Teacher Notes

Teaching move: Keep students focused on observable effects rather than invisible details they cannot measure directly.

Misconception to catch: Students may think the first object “loses everything.” Help them notice that both objects can still have motion after impact.

Student Worksheet

Name: ________________________ Date: ________________________

1️⃣ Collision observations

Test	What happened to object 1?	What happened to object 2?
Soft collision
Stronger collision

2️⃣ Explain the energy transfer

🔑 PARENT ANSWER KEY — Detach before giving worksheet to students

Sample explanation

The moving object transferred energy during the collision. The resting object began to move, and the stronger collision usually caused a bigger motion change.

✅ What Success Looks Like

Student describes both objects after the collision.
Student uses evidence from more than one test.
Student correctly connects collision to energy transfer and motion change.