A stronger push can change how far an object moves. Repeated tests help us spot the pattern.
📋 NGSS Standard: 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.
🎯 Learning Objective
Students will investigate motion Changes with Force, make observations during the lesson activity, and explain what they learned using evidence from the lesson.
💡 The Big Idea
A force can change an object's motion. When we compare a gentle push to a stronger push, we can collect evidence that stronger and weaker forces can change how far an object moves.
🔬 The Science
Science Snapshot
Motion changes are evidence that a force acted on the object.
What is happening?
A force can start, stop, speed up, slow down, or redirect an object. Motion changes when a push or pull is strong enough to overcome the forces already acting on the object.
Why it works that way
The same object can respond differently depending on how hard it is pushed and which direction the force acts. Motion is not random; it changes because of a specific interaction.
Look for this in the lesson
Students should connect the action to the motion result. That makes the lesson about cause and effect rather than simply watching things move.
Ask while you read: Which specific push or pull caused the motion to change, and how did it change?
📦 Materials
1 toy car, small block, or object that slides
1 flat table or smooth floor surface
Masking tape for a starting line
Ruler or measuring tape
Pencil
Printed Student Worksheet
🔬 Let's Get Started
Step 1 — Plan the Investigation (6 min) Set up one starting line and choose one object and one surface. Students make a prediction before testing: Which push strength will move the object farther, and why?
Step 2 — Define the Variable (6 min) Explain that the strength of the push is the only thing that should change. Keep the object, starting line, surface, and direction the same so the test stays fair.
Step 3 — Run 3 Gentle-Push Trials (10 min) Use a gentle push three times from the same starting line. Measure each distance in inches or centimeters and record all three results in the data table.
Step 4 — Run 3 Strong-Push Trials (10 min) Use a stronger push three times with the same object and setup. Measure and record each distance so students have two sets of comparable data.
Step 5 — Analyze the Data (8 min) Circle the longest distance in each group, then find the average for the gentle pushes and the strong pushes. Students can make a quick bar graph or compare the averages in words.
Step 6 — Make an Evidence-Based Claim (8 min) Write a conclusion using the data: "My strong pushes usually moved the object farther because..." Students should point to measured distances or averages, not just opinion.
💬 Discussion Questions
🗣️ Question 1: What pattern do you notice when you compare the average gentle push to the average strong push?Look for: The stronger push usually produced a larger average distance.
🗣️ Question 2: Why did we keep the object, surface, and starting line the same?Look for: Those controls make it a fair test, so push strength is the variable we can compare.
🗣️ Question 3: If one trial did not match the pattern, should we ignore all the other data?Look for: No. Scientists look at the full set of trials and explain outliers instead of relying on one result.
🗣️ Question 4: Which numbers from your table are the best evidence for your claim?Look for: Students should cite measured distances, averages, or a clear comparison across several trials.
✨ Extensions
📏 Average It: Find the average distance for gentle pushes and for strong pushes.
🧱 Change One Variable: Try a heavier object next. Does the same pattern still appear?
🚦 Real Life: Think of a time when a stronger push or pull changed motion in real life, like opening a door or kicking a ball.
👩🏫 Parent/Teacher Notes
Fair-test reminder: Keep the object and starting line the same. The lesson works best when students clearly see that push strength is the variable changing.
Measurement does not need to be perfect: The goal is pattern-finding, not exact lab precision.
Evidence language matters: Encourage students to point to measured distances or repeated observations, not just say “because it was stronger.”
Assessment check: Students should be able to make a claim and back it up with data from their chart.
I predict the __________________ push will move the object farther because ______________________________.
Part 2 — Record Your Tests
Trial
Type of Push
Distance Moved
1
Gentle
2
Gentle
3
Gentle
4
Strong
5
Strong
6
Strong
Average gentle push: __________________
Average strong push: __________________
Part 3 — Make a Claim with Evidence
Claim: When the push was stronger, the object __________________________________.
Evidence: The average gentle push was __________________ and the average strong push was __________________.
Reasoning: This shows force changed motion because __________________________________.
Part 4 — Draw or Graph the Data
Draw one gentle push and one strong push from the same starting line, or sketch a simple two-bar graph for your averages.
Draw here ✏️
🔑 Parent Answer Key
Detach note: This page is for parent/teacher reference. Student wording may vary if the science idea is correct.
Part 1
Predictions may vary, but students should expect the stronger push to move the object farther.
Part 2
Distances vary. Strong pushes should usually move the object farther than gentle pushes across the three-trial set.
Average answers will depend on the family's measurements.
Part 3
Claim: when the push was stronger, the object usually moved farther / changed motion more.
Evidence to look for: measured distances, averages, or a comparison across several trials.
Reasoning: a stronger force can change an object's motion more than a weaker force.
What Success Looks Like
Student compares stronger and weaker pushes correctly.
Student uses evidence from repeated tests or averages instead of guessing.
Student can explain that push strength was the variable that changed.
Student understands that keeping the object, surface, and start line the same helps make a fair comparison.
Troubleshooting / Misconceptions
If results are messy, remind students that repeated tests and averages matter more than one outlier.
If a student says “strong always means faster,” point back to the actual evidence they collected and discuss how we describe what we observed.
If averaging feels too advanced, compare all six trials verbally and circle the stronger pattern instead.
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