Intro to Power Lesson Plan Work Fast, Work Slow
An Intro to Power
7TH GRADE • PHYSICS
Duration
45 Minutes
Objective
Differentiate work & power
Key Concept
Rate of energy transfer
WHY THIS LESSON?
Understanding work and power helps students grasp fundamental physics concepts that apply to everyday activities, from lifting objects to running up stairs, building a foundational understanding for future science topics.
MATERIALS
Work vs. Power Slides
Stair Climbing Challenge Activity
Stopwatches / Phone timers
Measuring tapes & Calculators
Access to a staircase
TEACHER PREP
Pace: 15 minutes
Review slides & practice explanations.
Print Activity Worksheets (1 per student).
Scout a safe, nearby staircase for the lab.
Check that all stopwatches/calculators are working.
INSTRUCTIONAL STEPS
Step 01
Engage & Inquire
10 MIN
Opening Hook: Ask students: “What does it mean to be ‘powerful’?” Discuss initial ideas (strength, speed, money, energy).
Scientific Context: Introduce 'work' (Force x Distance). Distinguish it from homework or "going to work."
The Pivot: Ask: “Is lifting a heavy box slowly the same as lifting it quickly?” Let them debate briefly.
Step 02
Explore & Discover
20 MIN
Lab Launch: Group students (Timer, Recorder, Climber). Explain the goal: Measure your own power.
Data Collection: Guide students in measuring stair height and their own force (Weight in Newtons = lbs × 4.45).
Execution: Supervise students on stairs. Remind them to move fast but safely.
Step 03
Explain & Define
10 MIN
Direct Instruction: Use slides to formally define Power as the rate of work.
Connection: Use their lab results. Compare two students: one who climbed in 5s vs 8s. Who did more work? Who had more power?
Step 04
Apply & Extend
05 MIN
Reflection: Discuss real-world examples: cars with high horsepower, sprinting vs. jogging, lightbulbs (Watts).
Exit Ticket: Write down the difference between Work and Power in one sentence.
Work vs Power Slides What Makes You
Powerful?
What does it mean to be powerful in everyday life?
Who is more powerful: a slow, strong person or a fast, less strong person?
Teacher Note: Start by engaging students with what 'power' means to them. Transition to scientific work.
Work: The Definition
In science, Work is done when:
A Force acts on an object.
The object Moves a distance.
Movement is in the same direction as force.
Work = Force × Distance
Units: Joules (J)
Teacher Note: Emphasize that work requires motion. Pushing a wall is effort, but zero scientific work!
Power: Work Done FAST!
Power tells us how quickly work is done.
More Power = Same work, less time.
Less Power = Same work, more time.
P = W / T
Units: Watts (W)
Teacher Note: Introduce power as the rate. Use the analogy of sprinting vs. walking the same route.
Stair Climbing
Challenge!
You did 'work' by lifting your body weight against gravity.
Did everyone finish in the same time?
What does that reveal about your individual Power?
"It's not just about getting there, it's about how fast you go!"
Teacher Note: Connect lab experience to the concept. Ask students to share their times vs. their calculated power.
The Big Difference
Work
Effort applied over a distance.
Example: Lifting a backpack.
Power
How fast that effort is applied.
Example: Sprinting up the stairs.
Power is the RATE at which energy is transferred.
Stair Climbing Power Challenge Activity Physics Lab: Stair Climbing Power Challenge
Objective: Calculate the mechanical power generated during a vertical climb.
Lab #04
Student Name
Partner Name
Date
Part 1
Gather Your Data
1. Your Weight (Force)
Weight (lbs) × 4.45 = Weight (Newtons).
Force =
N
2. Height of One Stair
Measure the vertical rise of a single step.
Height =
m
3. Number of Stairs
Total count of stairs in the flight.
Count =
steps
4. Total Distance
Height × Count
Distance =
meters
5. Time to Climb
Climb safely and consistently.
SECONDS
Part 2
Calculations
WORK
Step 1: Calculate Total Work
Formula: Work (J) = Force (N) × Distance (m)
Force
×
Distance
=
JOULES (J)
POWER
Step 2: Calculate Your Power
Formula: Power (W) = Work (J) / Time (s)
Work
÷
Time
=
Watts (W)
Part 3
Reflect and Compare
1. Who in your group generated the most power? Why do you think that is?
2. If you climbed the stairs slower, would your power increase or decrease? Explain using the formula.
3. Describe another real-world scenario where high work is done with high power output.
