Force Detectives Lesson Plan
Force Detectives
Lesson Plan: Investigating Motion
Case #7-PHYS-01
Duration
30 Minutes
Audience
7th Grade
Approach
Hands-on Lab
Mission Objective
Students will investigate how pushes and pulls (forces) affect the motion of objects by conducting simple experiments, recording observations, and drawing conclusions.
The Evidence
"Understanding forces builds foundational physics knowledge and critical thinking, linking classroom concepts to everyday phenomena like pushing doors or rolling balls."
Preparation Checklist
Gather all physical materials: spring scale, toy cars, ramps, masses, stopwatches, meter sticks.
Print Investigating Forces Worksheet & Exit Ticket.
Set up demonstration area with a flat surface and ramp.
Queue up demonstration images or videos for the hook.
Equipment & Evidence
Investigation Timeline
5m
Hook: Everyday Forces
Project pictures or videos of people opening doors, pushing shopping carts, or kicking balls. Ask: "What forces are at work? Can you identify the push or pull?" Record responses on the whiteboard under "Pushes" and "Pulls."
5m
Teacher Demonstration
Use a spring scale to pull a block across a flat surface. Have students predict how force changes affect motion. Measure distance traveled in 5 seconds with varying force magnitudes. Discuss findings.
15m
Guided Investigation
Pairs use ramps and spring scales to apply three force levels (Low, Medium, High) to toy cars.
- Release car from fixed point with measured force.
- Time the journey over a fixed distance (e.g. 1m).
- Record data and calculate speed: \( \text{speed} = \frac{\text{distance}}{\text{time}} \)
3m
Share & Discuss
Invite pairs to share data. Discuss patterns: "How did force affect speed?" Link observations to the concept that greater force generally produces greater acceleration.
2m
Exit Ticket Assessment
Distribute exit tickets. Students define push/pull and provide examples. Collect to gauge understanding.
Force Detectives Slides
Case File: Motion
Force Detectives
Investigating the Science of Pushes and Pulls
Grade 7 Physics
Mission Brief
Objectives
- • Define push and pull
- • Observe how varying force changes motion
Investigation Agenda
- 1. The Hook (5 min)
- 2. Expert Demo (5 min)
- 3. Field Work (15 min)
- 4. Evidence Review (3 min)
- 5. Exit Briefing (2 min)
Hook: Everyday Forces
[Teacher: Show images/video of people pushing shopping carts, kicking balls, or opening doors here.]
"What forces are at work? Can you identify the push or pull?"
Identify the interactions as we look at the evidence.
What Is a Force?
A FORCE is a push or pull on an object.
Forces can change an object's speed or direction.
Push
Opening a door, kicking a ball
Pull
Tug-of-war, picking up a bag
Expert Demonstration
WATCH & PREDICT
1
Set the Scene
Attach a block to a spring scale on a flat surface.
2
Predict
How will increasing the pull affect the motion?
3
Test & Compare
Pull with low, medium, and high force. Measure distance in 5 seconds.
Live Experiment Station
Field Work: Investigation
Your Task
- Pair Up: Grab your gear (Scale, Car, Ramp, Timer).
- Setup: Set the ramp and mark a fixed distance.
- Trial: Use three different force levels (Low, Med, High).
- Record: Log Force, Time, and Distance on your worksheet.
The Calculation
SPEED = \( \frac{\text{Distance}}{\text{Time}} \)
Keep the ramp angle the same for every trial!
Evidence Review
?
Which force level produced the highest speed?
?
Did any results surprise you? (The Anomalies)
?
How does changing force relate to acceleration?
"Higher Force = Greater Change in Motion"
Investigating Forces Worksheet
Evidence Log: Investigating Forces
Confidential Case File
Lead Detective Name
Investigation Date
Investigation Objective
Use a spring scale to apply three different forces to a toy car on a ramp. Measure the time it takes to travel a fixed distance, then calculate the car's speed for each trial.
Equipment Checklist
- Spring Scale
- Toy Car
- Ramp
- Stopwatch
- Meter Stick
Field Procedures
- Mark a fixed distance (e.g. 1m) on your ramp.
- Attach the spring scale to the toy car.
- Keep the ramp angle constant for ALL trials.
- Apply 3 different forces (Low, Med, High) and release.
- Time the journey over the marked distance.
- Calculate speed using: \( \text{speed} = \frac{\text{distance}}{\text{time}} \).
| Trial | Force Applied (N) | Time (s) | Distance (m) | Speed (m/s) |
|---|
| 01 | | | | |
| 02 | | | | |
| 03 | | | | |
Analysis: Show Your Work
Calculate speed for all three trials below (Distance ÷ Time):
1
What trend do you observe between the force applied and the speed of the car? Explain your answer.
2
Did you notice any anomalies or unexpected results in your data? Suggest possible reasons for these results.
3
Based on your data, if you wanted the car to go twice as fast as in Trial 1, would you need to apply more force, less force, or the same force? Explain your reasoning.
