Energy Exchange Slides ENERGY EXCHANGE
Analyzing Potential and Kinetic Transformations
Warm Up: The Drop
Imagine a roller coaster at the peak of the first hill...
1. Where is the cart highest?
What kind of energy is stored here?
2. Where is the cart fastest?
What kind of energy is active here?
Scientific Tools
GPE
Gravitational Potential Energy
Energy stored in an object because of its height above the ground.
KE
Kinetic Energy
The energy of motion. Any object that is moving has kinetic energy.
"What energy transformations take place when a ball is raised and released?"
Newton's Cradle Case Study
Embedded media
Newton's Cradle: Potential and Kinetic Energy
PAUSE @ 0:29
Peak Height
The Evidence:
Discussion:
"Why is the Kinetic energy bar at zero right now?"
PAUSE @ 0:37
The Bottom Swing
The Evidence:
The Kinetic bar is full.
The GPE bar is at zero.
Discussion:
"Where did all that Potential energy go as the ball swung down?"
PAUSE @ 0:44
The Collision
Mystery Bar
Elastic Potential Energy
At the micro-second of impact, the steel balls compress like tiny springs. This stores energy temporarily before transferring it!
"What is physically happening to the metal balls at this exact micro-second?"
Graphing the Swing
Your Mission:
The Total Truth
"If we added the value of the PE bar and KE bar together at any moment, what would the total look like?"
Total Mechanical Energy
Energy is never created or destroyed. It only changes form.
Energy Exchange Worksheet Energy Exchange
Newton's Cradle Analysis
Student:
Date:
Period:
Part 1: The Roller Coaster
1. At the highest point of the first hill, the cart has the most:
Kinetic Energy
Potential Energy
2. At the fastest point at the bottom of the hill, the cart has the most:
Kinetic Energy
Potential Energy
Part 2: Newton's Cradle Data
As we watch the video, record the height of the energy bars (Full, Empty, or Rising/Falling) at each timestamp.
Timestamp Ball Position GPE Bar Kinetic Bar Elastic Bar 0:29 Peak height (Top) 0:37 Bottom of swing 0:44 Moment of Impact
Part 3: Graphing the Swing
INSTRUCTIONS:
Sketch two separate lines representing the energy during one full swing (starting at the top left, swinging through the bottom, and ending at the top right). Use a solid line for GPE and a dashed line for KE.
Energy Level
PEAK (Left)
Bottom of Arc
PEAK (Right)
MAX
ZERO
Position of Ball during swing
3. Circle the point on your graph with "Max PE".
Why is the PE highest at this exact point?
4. Circle the point on your graph with "Max KE".
How does the ball's speed relate to this point?
Part 4: The Total Truth
Total Energy Line:
Big Idea: The Law of Conservation of Energy states that energy is never or . It only from one form to another.
Draw a straight horizontal line on the box to the left representing the Total Mechanical Energy of the system.
Energy Exchange Teacher Guide Teacher Guide
Energy Exchange
Lesson: Energy Exchange
Grades: 6-8 Science
Objective
Students will be able to construct a graph representing the inverse relationship between potential and kinetic energy in a closed system (Newton's Cradle).
Essential Question
"What energy transformations take place when a ball is raised and released?"
Required Materials
Slide Deck
Student Worksheet
YouTube Access
Pencils & Colors
Pacing & Facilitation
0-5 MIN
Warm-Up: The Roller Coaster
Use Slide 2. Establish baseline definitions of GPE (height) and KE (motion). Most students intuitively understand the roller coaster peaks and valleys.
5-15 MIN
Video Observation & Pausing
Play the Newton's Cradle video. CRITICAL PAUSES:
0:29: GPE is max. Ball is momentarily stopped (KE is 0).0:37: KE is max. Ball is at lowest point (GPE is 0).0:44: Discuss "Elastic Energy" — Energy isn't "gone" during collision; it's just being stored as deformation in the metal.
15-40 MIN
Main Activity: Graphing the Swing
Students sketch the energy lines. Encourage them to use two different colors (blue for PE, yellow/orange for KE). Monitor for the "X" shape created as PE drops and KE rises.
40-45 MIN
Closure: The Total Truth
The "Big Reveal" of the horizontal line representing Total Mechanical Energy. This is the cornerstone of Conservation of Energy.
Worksheet Answer Key
Part 1 Answers
1. Potential Energy | 2. Kinetic Energy
Part 2 Table
0:29: GPE=Full | KE=Empty | Elastic=Empty0:37: GPE=Empty | KE=Full | Elastic=Empty0:44: GPE=Falling | KE=Falling | Elastic=Spiking
Part 4 Closure
"Energy is never created or destroyed . It only transforms/changes from one form to another."
Graph Visualization (Target Result)
Peak L
Bottom
Peak R
Teacher Tip: Watch for students drawing straight diagonal lines (V-shape). While acceptable for middle school, energy transformations in a pendulum follow a sinusoidal/curved path. Either is a "win" for conceptual understanding!
