Energy Swing Slides Physical Science
Energy Swing
Potential, Kinetic, and Conservation
Today's Mission
01
Define Conservation
Explain why energy can't be created or destroyed, only traded.
02
Pinpoint Energy States
Identify the exact moments of maximum PE and KE in a moving system.
Warm-Up
PhET Energy Skate Park
Open the simulation and observe the Bar Graphs as the skater moves.
When is PE the highest?
When is KE the highest?
What happens to the Total Energy ?
Link: bit.ly/phet-skate-energy
Simulation Launch
Observation: The Energy Trade
Embedded media
Look for
The girl on the swing analogy (2:28 - 3:52)
Discussion Question
Why is her Kinetic Energy zero at the top?
The Big Idea
GPE
Gravitational Potential Energy
\( mgh \)
Stored energy based on height .
KE
Kinetic Energy
\( \frac{1}{2}mv^2 \)
Energy of motion (velocity).
Total
Law of Conservation
\( PE_i + KE_i = PE_f + KE_f \)
Total energy stays the same .
Pendulum Power Lab
1
Measure the height of your release point.
2
Observe the speed at the bottom of the arc.
3
Diagram the PE and KE transitions.
25 Minutes
Pair Collaboration
Energy Swing Worksheet Energy Swing Lab
Conservation of Energy & Pendulum Dynamics
Name:
Date:
Part 1: PhET Skate Park
Watch the skater on the track. Observe the Bar Graphs for Kinetic Energy (KE), Potential Energy (PE), and Total Energy.
1. Where on the track is the Potential Energy (PE) at its maximum height?
2. What happens to the "Total Energy" bar as the skater moves?
Part 2: The Swing Analogy
During the video, we saw a girl on a swing. At the highest point of her arc, the narrator said she has zero Kinetic Energy .
Reflect:
Why is her Kinetic Energy zero at that exact moment? What is her body actually doing?
Part 3: Pendulum Power Lab
Procedure
Tie the washer to a 30cm string.
Hold the string from a fixed point.
Pull back to your release height.
Observe the speed at the bottom.
Data Collection
Release Height (cm):
Observed Speed at Bottom: Fast / Slow
Energy Diagram
Sketch your pendulum's path. Label Max PE , Max KE , and the Transition Points .
Law of Conservation
Energy is never created or destroyed; it only changes form.
Potential (PE)
Stored energy based on height or arrangement.
Kinetic (KE)
Energy of motion. If it moves, it has KE.
Energy Swing Exit Ticket Exit Ticket
Lesson: Energy Swing
Student Name
Date
The Pendulum Sketch
Sketch a simple pendulum in motion. Your diagram must clearly show:
Label Max PE
Label Max KE
Conservation Check:
In one sentence, what happens to the Total Energy of the pendulum as it swings from the top to the bottom?
Energy Swing Teacher Guide Teacher Resource
Energy Swing Guide
8th Grade Physical Science • Lesson Facilitation & Keys
Time Required
50 Minutes
Learning Objectives
Define the Law of Conservation of Energy .
Identify points of maximum Potential Energy (PE) and Kinetic Energy (KE) in a swing system.
Calculate or describe the trade-off between energy forms using \( PE_i + KE_i = PE_f + KE_f \).
Pacing Guide
<table class="w-full border-collapse"><tbody><tr class="border-b border-slate-100"><td class="py-2 font-bold text-slate-700 w-24">0-5 min</td><td class="py-2 text-slate-600"><strong>Warm-up:</strong> PhET Energy Skate Park exploration.</td></tr><tr class="border-b border-slate-100"><td class="py-2 font-bold text-slate-700">5-15 min</td><td class="py-2 text-slate-600"><strong>Video Analysis:</strong> Watch through 3:52 & discuss.</td></tr><tr class="border-b border-slate-100"><td class="py-2 font-bold text-slate-700">15-40 min</td><td class="py-2 text-slate-600"><strong>Hands-on:</strong> Pendulum Lab Activity.</td></tr><tr class="border-b border-slate-100"><td class="py-2 font-bold text-slate-700">40-45 min</td><td class="py-2 text-slate-600"><strong>Diagramming:</strong> Completing the worksheet analysis.</td></tr><tr class="border-b border-slate-100"><td class="py-2 font-bold text-slate-700">45-50 min</td><td class="py-2 text-slate-600"><strong>Closure:</strong> Exit Ticket assessment.</td></tr></tbody></table>
Required Materials
Computers/Tablets (PhET)
String (30-50cm)
Washers or fishing weights
Metric rulers / Tape measures
Stopwatches (optional)
Facilitation Notes
Video Discussion Guide
Key Question: "Why did the narrator say the girl has zero KE at the top of the swing?"
"At the highest point of her arc, her velocity is momentarily zero as she changes direction. Since \( KE = \frac{1}{2}mv^2 \), if \( v=0 \), then \( KE=0 \)."
Lab Success Tips
Release: Remind students not to "push" the pendulum. It should be a clean drop.Safety: Ensure students are standing away from the swing path to avoid getting hit by the washer.Observations: Encourage them to look for the "blur" at the bottom (Max speed/KE).
Worksheet & Exit Ticket Answer Key
1. PhET Exploration
Max PE: At the highest point of the track (either side).Total Energy: Stays constant/flat on the bar graph (demonstrating conservation).
