PhET Demos Photonics
INTRODUCTION
This mini website attempts for other Sections to be inspired in adapting or adopting this approach of STEM outreach at a low cost.
Demos to illustrate Photonics Concepts
In terms of IEEE leadership development, you can relate optical paths to caeer paths.
You can have student branches or section volunteers to help develop short 5-minute videos on each concept in physics, math, engineering topics, leadership of lessons learned and post it on YouTube. John Santiago, Charles Stein, Lucy Talley and Kate Landow can collect and consolidate these videos to form video playlists of sample lessons to deliver for educators, home school parents and other stakeholders. Each section can post their versions of playlists on their section websites to meet their local community needs.
Other examples of PhET simulations that can be used for empowered Section members can be found at:
- Interactive PhET simulations on electrical fundamentals: PhET Demos | IEEE Pikes Peak Section
- Interactive PhET simulations on math fundamentals: PhET Demos – Math | IEEE Pikes Peak Section
- Colorado University 170+PhET Simulations at: PhET: Free online physics, chemistry, biology, earth science and math simulations
Six Lessons on Photonics
Demos to illustrate Photonics Concepts
Lesson 1 — Bending Light → Scattering Experiment
Students see real-world deviation of light (diffusion, divergence).
Lesson 2 — Color & Spectrum → Color Filters + Prismatic Film
Perfect match for wavelength, RGB addition, absorption.
Lesson 3 — Light Sources → Phototransistor Control
Introduces practical light sources + detection.
Lesson 4 — Waves on a String → Strobe Timing
Allows students to experience pulse timing and oscillations, equivalent to wave concepts.
Lesson 5 — Geometric Optics → Light-Driven Motor
Demonstrates control and alignment of light affecting real motion.
Lesson 6 — Wave Interference → Fiber Optics Communication
Students visualize containment, transmission, and loss—core to wave interference and optics.
Week 1 — Light Behavior (Reflection & Refraction)
PhET Demo: Bending Light
Snap Circuits Project:
Project #129 — Single LED Tower / Light Scattering Demo
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Students observe directionality vs spread
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Connects to ray behavior and angle effects
Why this matches:
PhET shows idealized ray paths; the LED tower shows real-world divergence, intensity changes, and scattering.
SNAP Circuits – Light
WEEK 1 — LED Tower / Light Scattering
Closest Match: Scattering Light
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Project 53 — Scattering Light
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Appears on p. 31 of the PDF
(Found under the “Scattering Light” demonstration using LED + translucent materials)
Evidence:
“Project 53 Scattering Light… Semi-transparent materials scatter the light…”
This is the best match for teaching ray behavior, diffusion, and light-tower effects.
Week 2 — Color as Information (Spectrum & Perception)
PhET Demo: Color Vision
Snap Circuits Project:
Project #136 — Color LEDs + Filters
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Students mix LED colors
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Use physical color filters to see wavelength-dependent transmission
Why this matches:
PhET teaches how RGB produces color; Snap Circuits shows real absorption and filtering.
SNAP Circuits – Light
WEEK 2 — RGB LEDs + Color Filters
Closest Match: Color Filters + Color Mixing
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Color Filters explanation — p. 11
(Manual text introducing red/green/blue filters)
Evidence:
“Color filters allow one color to pass… This set includes red, green, and blue filters…” -
Project 51 — Prismatic Film / Color Separation — p. 32
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Project 52 — View Lights Through Filters — p. 32
These are the closest operational matches for RGB + filter demonstrations.
Week 3 — Light Detection (Sensors & Thresholds)
PhET Demo: Photoelectric Effect (Conceptual)
Snap Circuits Project:
Project #140 — Phototransistor Triggering LED / Fan / Alarm
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Students test sensor activation
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Explore distance, angle, noise
Why this matches:
PhET shows how light energy can release electrons; Snap Circuits shows how light changes circuit behavior.
SNAP Circuits – Light
WEEK 3 — Phototransistor Light Detection
Closest Match: Photo Light Control
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Project 79 — Photo Light Control
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Appears on p. 40 of the PDF
Evidence:
“Control the white LED brightness by varying the amount of light on the phototransistor…”
This is a perfect match for “light → electrical signal”.
A strong second alternative:
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Project 76 — Photo Current Amplifier (p. 39)
Also uses phototransistor sensing.
PhET Demo: Wave Properties (timing, pulses)
Snap Circuits Project:
Project #172 — Morse Code LED (Pulse Duration Modulation)
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Students send dots & dashes
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Explore timing as information
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Receiver decodes visually or with phototransistor
Why this matches:
PhET establishes signal timing; Snap Circuits implements pulse-duration modulation (PDM).
SNAP Circuits – Light
Week 4: Morse Code Timing / Light Pulses
Closest Match: Strobe Light (manual timing pulses)
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Project 15 — Strobe Light — p. 21
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Project 16 — Color Strobe Light — p. 21
Evidence:
“Strobe light… when S2 is pressed the light may be blinking…”
Why this is the best match:
Students can press the switch manually to create timed pulses → same principle as Morse code or pulse-duration modulation.
Week 5 — Light → Decisions (Sensing for Automation)
PhET Demo: Any sensor-related model OR Ozobot demo
Snap Circuits Project:
Project #184 — Light-Controlled Motor / Fan (LDR or Phototransistor)
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Light triggers an action
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Demonstrates “light as decision input”
Why this matches:
This builds the concept of light-driven logic, which sets up autonomy (robots, machines, etc.).
Week 6 — Fiber Optics & Detection (Capstone)
PhET Demo:
Choose ONE:
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Bending Light (Total Internal Reflection)
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Geometric Optics (recommended alternative)
SNAP Circuits – Light
WEEK 5 — Light-Controlled Motor
Closest Match: Photo-controlled Motor Speed
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Project 46 — Delayed Photo Speed Control — p. 32
Evidence:
“As you move your hand over the phototransistor, the motor slows…”
This is exactly “light → decisions”.
A second option:
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Project 65 — Day Blinker (p. 36)
SNELL’S LAW FOR MIDDLE SCHOOLERS
🦁🐬🦁 Explaining the Picture: Snell’s Law for Middle School
What you’re looking at
Imagine you’re watching a relay race where an animal has to get from Point A to Point B as fast as possible.
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On land, the animal is a lion 🦁 — strong and fast at running
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In water, the animal becomes a dolphin 🐬 — fast at swimming
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From the sky, an eagle 🦅 watches everything to see which path is best
The picture shows how the path changes when the animal moves from land into water and back onto land.
🟢 Point A → 🟢 Point B
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Point A is where the animal starts.
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Point B is where it wants to finish.
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The goal is not the shortest path, but the fastest path.
That’s the most important idea.
