4-PS3-3: Energy Changes in Collisions
Also called NGSS 4-PS3-3 · Topic: Energy · Physical Science
The Official Wording
Ask questions and predict outcomes about the changes in energy that occur when objects collide.
Clarification statement: Emphasis is on the change in the energy due to the change in speed, not on the forces, as objects interact.
Assessment boundary: Assessment does not include quantitative measurements of energy.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 4-PS3-3 Means in Plain English
Fourth graders ask questions and make predictions about what happens to energy when two objects crash into each other. They watch a moving object slow down as it hits a resting one, and they notice the resting one start to move, often with a sound.
The focus is on speed changing, not on the forces between the objects, and no energy is measured. It builds on linking speed to energy (4-PS3-1) and leads to middle school work on kinetic energy and collisions (MS-PS3-5).
4-PS3-3 I Can Statements
- I can predict what happens to speed when two objects collide.
- I can explain where a moving object's energy goes in a crash.
- I can ask a testable question about a collision.
4-PS3-3 Worked Example
A collision test a class can run at their desks with two marbles and grooved plastic rulers.
When a rolling marble hits a resting marble, where does its energy go?
Set It Up: Two same-size glass marbles, two grooved plastic rulers laid end to end as a track, and a book to tilt the first ruler into a ramp.
- Before rolling, write a prediction: what will each marble do after the hit?Predictions on sticky notes
- Place one marble at rest in the groove of the flat ruler.Target marble waits
- Release the second marble from the top of the ramp and watch closely.A click, then the first marble almost stops
- Note what the resting marble does after the hit.It rolls off down the track
- Release from higher up the ramp and compare.Faster hit: target rolls farther
The rolling marble nearly stopped and the resting marble rolled away, and a faster first marble sent the second one farther.
Why it works: In a collision, energy passes from the moving object to the one it hits, and a little turns into sound.
Common Mistakes with 4-PS3-3
Thinking energy disappears
“The marble stopped, so its energy is gone.”
Try this: Look at what else changed. The energy moved into the other marble's motion and into the click you heard. It did not vanish.
Explaining only with pushes
“The marble pushed the other one, that's all.”
Try this: Describe the speeds: which marble slowed down and which sped up. Speed changes tell you where the energy went.
Asking questions you cannot test
“Why are marbles fun?”
Try this: Ask a question you can answer by changing one thing, such as whether a faster first marble sends the second one farther.
Where 4-PS3-3 Fits
Practice 4-PS3-3
Quick Check
- A fast toy car hits a parked one. What happens to the fast car's speed?
- What clue tells you some energy turned into sound?
- Will a faster or a slower marble make the resting marble roll farther?