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Physical Science Enhancement - Physics 1 - Waves and resonance

Introduction

Vibrations are everywhere—from guitar strings and voice cords to bridges and medical scanners. In this unit you’ll see how repeating motions create waves that transfer energy and information without moving matter overall, building from simple slinky pulses to resonance in strings, air columns and real-world systems.

Content

PS1.1 — Introduction to Waves

This lesson links to your everyday experiences of motion and sound: we’ll define waves as energy transfer without net movement of matter, compare transverse and longitudinal waves, and gather quick timing data with a slinky within our 30-minute working window.

Objectives

Key Ideas & Example

Transverse: oscillations ⟂ direction (string, light-model). Longitudinal: oscillations ∥ direction (sound). Terms: crest, trough, compression, rarefaction, amplitude, λ, f, T = 1/f.

Example: A water wave has λ = 0.80 m and f = 2.5 Hz → v = f λ = 2.0 m·s-1.

Activity — Measuring wave speed with a slinky

Apparatus and materials

  • Slinky (1 per group of 3), floor tape markers every 1 m, two metre sticks/tape measures.
  • Phone stopwatch (slow-motion video optional), worksheet/data table.

Procedure (30-minute working window)

  • Lay the slinky straight between two students ~4–6 m apart; mark 0 m and 3.0 m on the floor.
  • Transverse pulse: Send a single sideways flick. Time how long the crest travels 3.0 m. Repeat ×3; average.
  • Compute v = distance/time. Gently increase initial stretch (tension) and note qualitative change in v.
  • Longitudinal pulse: Push–release along the slinky to create a compression. Repeat timing and compare.
  • Optional (fast groups): Film a short train of pulses; estimate λ from frames, then use f = v/λ.

Safety

  • Keep the walkway clear; work at floor level; avoid overstretching (pinch risk).

Data prompts

Summary

  • Waves transfer energy without net matter transport.
  • Transverse vs longitudinal identified by oscillation direction.
  • Wave equation: v = f λ; tension affects wave speed on strings/slinkies.

Check your understanding

1) Give one real example of a transverse wave and one of a longitudinal wave.

2) A wave moves at 1.8 m·s-1 with λ = 0.60 m. Find f.

3) If tension increases and frequency stays similar, what happens to λ according to v = f λ?

PS1.2 — Wave interference basics

Last lesson you explored the difference between transverse and longitudinal waves and used a slinky to measure wave speed. In this lesson we build on that by overlapping pulses to see how waves combine — the principle of superposition. You’ll use a simulation to investigate constructive and destructive interference.

Objectives

Key Ideas & Example

Superposition principle: When two waves meet, their displacements add. After they pass, they continue unchanged.

Constructive interference: Crest + crest → larger crest. Compression + compression → stronger compression.

Destructive interference: Crest + trough (equal size) → cancel (zero displacement).

Example: Two pulses of amplitude 3 cm and 2 cm meet. For an instant the total displacement is 5 cm (constructive).

Activity — Interference with PhET Waves on a String

Apparatus and materials

Procedure (30-minute working window)

  • Open the PhET simulation in “Pulse” mode. Send a single pulse from the left.
  • Now send two pulses from opposite ends. Pause and sketch the superposition when they overlap. Then un-pause to see each pulse continue unchanged.
  • Switch to “Oscillate” mode. Set frequency = 1.5 Hz, amplitude = 0.5. Observe what happens when reflected waves overlap the incoming ones.
  • Record one clear example of constructive interference and one of destructive interference.
  • Extension (fast groups): try a higher frequency and note if overlapping creates a repeating pattern (standing waves).

Safety

  • No hazards (simulation-based). Remind students to stay on-task and record observations, not just “play.”

Discussion prompts

Summary

  • Superposition: displacements add while waves overlap.
  • Constructive = reinforcement; destructive = cancellation.
  • After passing, waves continue unchanged.

Check your understanding

1) Two pulses of +4 cm and –4 cm overlap perfectly. What is the displacement at that point?

2) Which type of interference occurs when a compression meets a rarefaction?

3) How does the PhET simulation show that waves do not permanently change each other after overlap?

PS1.3 — Wave interference circus

In the previous lesson you modelled interference using a simulation. Now you will see real demonstrations of interference across different kinds of waves — water, light, microwaves and sound — in a “circus” format. Each group rotates between short stations, making quick observations and sketches.

Objectives

Key Ideas

Interference patterns appear when two or more waves overlap. The regular bands or spots of bright/dark (or loud/quiet) regions are a direct result of constructive and destructive superposition. These effects demonstrate that light, sound and water all behave as waves.

Activity — Interference Circus

Apparatus and materials

  • Ripple tank with two point dippers (for water wave interference).
  • Laser pointer with double slit slide (for light interference — darkened room or safety goggles as appropriate).
  • Microwave oven with safe test area (e.g. marshmallows or chocolate slab method to show hot/cold spots).
  • Ultrasound emitter pair (or speaker interference demo, if ultrasound not available).
  • Worksheets with tables for each station.

Procedure (30-minute working window)

  • Divide class into small groups (3–4 students). Each group starts at a different station.
  • At each station, spend ~6–7 minutes observing the interference pattern and making a sketch.
  • Record whether you see constructive (bright/loud/high splash) or destructive (dark/quiet/flat water) regions.
  • After 2 stations, rotate. Aim to complete 3–4 stations in 30 minutes.
  • Back in class discussion, compare similarities between different media.

Safety

  • Ripple tank: water spillage hazard → use towels, mop up immediately.
  • Laser: never shine directly into eyes; supervise closely.
  • Microwave: teacher-only setup; no metal inside; handle hot food carefully.
  • Ultrasound/speakers: keep volume at safe level.

Observation prompts

Summary

  • Interference occurs in many different types of waves, not just one medium.
  • Constructive and destructive regions appear as bright/dark, loud/quiet, high/flat depending on the wave type.
  • These patterns support the wave model of light, sound and water.

Check your understanding

1) In the microwave marshmallow demo, why are some spots melted while others stay cool?

2) How does the ripple tank help us “see” interference that is harder to notice with sound?

3) What common feature links interference in water, light and sound?

PS1.4 — Standing waves and resonance intro

Previously you saw interference patterns in different media. In this lesson we explore what happens when two identical waves travel in opposite directions: they interfere to create a standing wave. Standing waves are closely linked to resonance, when a system naturally oscillates at certain frequencies with large amplitude.

Objectives

Key Ideas & Example

Standing waves: result from interference of two waves of the same frequency and amplitude travelling in opposite directions. They create fixed nodes and antinodes.

Resonance: occurs when a system is driven at its natural frequency, producing large amplitude vibrations.

Example: A string 1.2 m long vibrates in its fundamental mode (one half wavelength fits the string). λ = 2 × 1.2 = 2.4 m. If frequency f = 60 Hz, then v = f λ = 144 m·s-1.

Activity — Standing waves on a string/metal strip/air column

Apparatus and materials

  • Vibrating string setup (string, pulley, weights, vibration driver if available) OR metal strips clamped at one end.
  • Resonance tube with tuning fork (alternative air column demo).
  • Stopwatch, metre stick, worksheet for sketches.

Procedure (30-minute working window)

  • Set up a stretched string with adjustable length/tension. Drive it at low frequency and increase gradually.
  • Observe when stable patterns appear: clear nodes and antinodes form → resonance condition.
  • Sketch the fundamental mode (one half wavelength) and one higher mode.
  • Use measured length (L) and observed frequency (f) to calculate wave speed using v = f λ, where λ = 2L for fundamental.
  • Teacher demo: resonance tube with tuning fork or vibrating metal strip. Optionally show Chladni plate pattern for solids.

Safety

  • Ensure weights on string setup are secure; avoid snapping string under high tension.
  • Metal strips: supervise clamping; do not overstress the strip.
  • Resonance tube: avoid spilling water if used with variable-length tube.

Discussion prompts

Summary

  • Standing waves form from interference of opposite travelling waves of same frequency and amplitude.
  • Nodes = no motion, antinodes = maximum motion.
  • Resonance occurs when a system is driven at its natural frequency, producing large amplitude.
  • Wave speed can be calculated with v = f λ.

Check your understanding

1) What is the difference between a node and an antinode?

2) A string 0.80 m long vibrates in its fundamental mode at 50 Hz. What is the wave speed?

3) Why does amplitude become very large when the driving frequency matches the natural frequency of the system?

PS1.5 — Resonance demos

Last lesson you created standing waves and saw how resonance produces large amplitude at certain frequencies. In this lesson we extend those ideas with striking demonstrations — from a wine glass to a mass–spring system — and use a simulation to reinforce the concept of natural frequency.

Objectives

Key Ideas & Example

Natural frequency: the frequency at which a system oscillates when disturbed.

Resonance: when an external force drives the system at this frequency, the amplitude becomes very large.

Example: A 512 Hz tuning fork resonates with a 0.167 m air column (quarter wavelength). λ = 4L = 0.668 m → v = f λ = 342 m·s-1, consistent with speed of sound in air.

Activity — Resonance demos and simulation

Apparatus and materials

  • Wine glass (teacher demo only).
  • Mass–spring system with driver (lab stand + slotted masses).
  • Tuning fork and resonance tube (or bottle of water as simple air column).
  • Computer/tablet with PhET Resonance Simulation.
  • Worksheets with space for sketches and notes.

Procedure (30-minute working window)

  • Teacher demo: Rub finger around rim of wine glass to produce standing waves. Discuss why glass vibrates strongly at its natural frequency.
  • Group activity: Mass–spring driver: vary driving frequency. Note when amplitude is largest → record as resonance frequency.
  • Air column demo: Strike tuning fork, hold over tube/bottle with adjustable water level. Find resonance length where sound is loudest. Record L, calculate λ = 4L, then v = fλ.
  • Extension: Use PhET Resonance sim to try multiple systems and identify resonance frequencies.

Safety

  • Wine glass: handle carefully; stop if cracks appear.
  • Mass–spring: secure stand; avoid over-stretching spring.
  • Resonance tube: take care with water; wipe up spills promptly.

Discussion prompts

Summary

  • Resonance = large amplitude response when driven at natural frequency.
  • Wine glass, spring–mass, and air column provide clear demonstrations.
  • Wave equation links resonance tube data to sound speed in air.

Check your understanding

1) A 440 Hz tuning fork resonates with an air column of 0.195 m. What is the speed of sound calculated from this?

2) Why does rubbing a wine glass rim at the right speed produce such a loud tone?

3) How could resonance be useful in designing a musical instrument?

PS1.6 — Factors affecting resonance

Last lesson you saw dramatic resonance effects in glass, springs and air columns. This lesson investigates which factors affect the resonant frequency of a vibrating system. You will vary length and tension of a string and record how these changes shift the resonance condition.

Objectives

Key Ideas & Example

Resonance in strings: The fundamental mode has λ = 2L. So f = v / (2L). Wave speed v depends on tension (T) and mass per unit length (μ).

Increasing tension → higher v → higher f. Increasing length → larger λ → lower f.

Example: String length 0.80 m resonates at 200 Hz. If tension is doubled (wave speed √2 ×), frequency rises to about 280 Hz.

Activity — Investigating length and tension

Apparatus and materials

  • String vibration setup with pulley and hanging masses.
  • Vibration driver or tuning fork (to provide driving frequency).
  • Metre stick, stopwatch (optional), worksheet for results table.

Procedure (30-minute working window)

  • Set the string length to 0.80 m with a moderate tension. Drive at resonance, record frequency (from driver or tuning fork).
  • Shorten the string to 0.60 m, keeping tension the same. Observe change in resonance frequency.
  • Keep length constant, double the hanging mass (double the tension). Observe new resonance frequency.
  • Record all results in a table: Length, Tension (qualitative), Resonant frequency.
  • Extension (fast groups): Plot f vs 1/L for fixed tension; look for linear trend.

Safety

  • Ensure weights are secure and cannot fall on feet.
  • Do not overtighten the string; replace if fraying.

Data prompts

Summary

  • Resonant frequency depends on both length and wave speed in the string.
  • Shorter length → higher frequency; longer length → lower frequency.
  • More tension → higher wave speed → higher frequency.

Check your understanding

1) If a string resonates at 150 Hz when 1.0 m long, what will happen to the frequency if the length is halved?

2) Doubling the tension increases wave speed by √2. How will this affect frequency?

3) Which variable — length or tension — is easier to adjust in real musical instruments?

PS1.7 — Applications of resonance

Last lesson you investigated how length and tension change resonant frequency in a string. Today you’ll explore how resonance is applied — and sometimes causes problems — in real-life contexts, from musical instruments to buildings and medical imaging.

Objectives

Key Ideas & Example

Musical instruments: strings, pipes and drums resonate to produce loud, clear tones.

Engineering: bridges and buildings must avoid resonating with earthquake or wind frequencies.

Medicine: MRI and ultrasound use resonance of nuclei and tissues for imaging and treatment.

Example: The Tacoma Narrows Bridge collapsed in 1940 because wind drove it at a natural frequency, producing destructive resonance.

Activity — Resonance research carousel

Apparatus and materials

  • Short case-study sheets or webpages on: musical instruments, bridges, MRI, ultrasound.
  • Worksheet with space for notes from each case.

Procedure (30-minute working window)

  • Divide into four groups. Each group starts with one case study.
  • Spend ~7 minutes extracting key points: system, natural frequency, how resonance is useful or harmful.
  • After time, rotate groups and repeat with a new case. Continue until all groups have seen all cases (or 3 if time limited).
  • Return to starting group and prepare a 2-minute summary to share with class.

Safety

  • No hazards (paper/computer-based activity). Ensure focus on key science ideas rather than copying text.

Discussion prompts

Summary

  • Resonance can be harnessed (music, medicine) or prevented (engineering).
  • All examples rely on natural frequency and large amplitude when driven at that frequency.
  • Real-world contexts show why resonance is both powerful and important to understand.

Check your understanding

1) Why is resonance useful in a violin but dangerous in a suspension bridge?

2) How does MRI use resonance in the human body?

3) Suggest one way engineers can prevent harmful resonance in buildings.

PS1.8 — Mini project work begins

Last lesson you researched real-life applications of resonance. Now it’s your turn to design and build a simple resonant system. This could be a musical instrument, a model bridge, a resonating tube, or another creative idea. Today’s focus is on planning and starting construction.

Objectives

Project ideas

  • String instrument: rubber bands over a box, changing length/tension to alter pitch.
  • Resonant tube: cardboard/PVC pipe producing tones when blown across or tapped.
  • Bridge model: structure of straws/wood strips vibrating differently with changing supports.
  • Wine glass demo: explain how rubbing creates standing waves in glass walls.

Activity — Project planning and initial build

Apparatus and materials

  • Basic craft materials: cardboard, rubber bands, string, tape, scissors, glue.
  • Optional extras: PVC tubes, wooden sticks, plastic bottles, paper clips, balloons.
  • Worksheets for project plan (design sketch, materials list, resonance explanation).

Procedure (30-minute working window)

  • In groups of 3–4, select one project idea or propose an alternative approved by teacher.
  • Draw a simple design sketch. Label parts where resonance will occur (string length, tube length, supports etc.).
  • List materials required. Gather from class supply and begin basic assembly.
  • Write 2–3 sentences explaining the resonance principle behind your design.
  • By end of lesson: submit a rough plan + start of construction for teacher feedback.

Safety

  • Handle scissors/cutters carefully. Use hot glue only under supervision if provided.
  • Keep work area tidy; clean up loose materials to avoid slips.

Planning prompts

Summary

  • You will design and build a resonant system in a small group.
  • Resonance principles must be shown clearly in your design (standing waves, natural frequency).
  • Today’s goal: sketch, gather materials, start construction, and prepare for testing.

Check your understanding

1) What is the natural frequency of a system?

2) Name two different types of systems where resonance can occur.

3) How will your group demonstrate resonance in your project?

PS1.9 — Project completion & testing

Last lesson you planned and began building a resonant system. In this lesson you will complete your construction, test how well it demonstrates resonance, and collect data or observations to support your explanation.

Objectives

Testing ideas

  • String/rubber band instrument: measure frequency with phone app; change length/tension to compare pitch.
  • Resonant tube: vary water level or tube length; listen for loudest sound when in resonance.
  • Bridge model: tap gently or use speaker vibration; watch for strong oscillation at certain frequency.
  • Wine glass demo: show how rubbing or sound at right frequency makes strong vibration.

Activity — Project completion and testing

Apparatus and materials

  • Materials from previous lesson’s builds (string, boxes, tubes, sticks, tape, etc.).
  • Phones/tablets for sound apps or video recording (optional).
  • Worksheets/logbooks for data and observations.

Procedure (30-minute working window)

  • Complete assembly of your resonant system in your group.
  • Test the system: adjust length, tension, or driving frequency until resonance is clear.
  • Record at least 2–3 clear observations or measurements (e.g. resonant length, frequency, qualitative loudness).
  • Prepare a short explanation of how your system shows resonance.
  • By end of lesson: project should be complete and tested, ready for presentation next time.

Safety

  • Handle tools and materials carefully; keep workspace clear.
  • Do not overstretch strings/bands to breaking point.
  • Clean up spills immediately if using water in tubes.

Discussion prompts

Summary

  • Each group completed and tested their resonant system.
  • Evidence of resonance was observed and recorded (e.g. loudness peaks, strong vibrations, node/antinode patterns).
  • Projects are now ready for presentation and explanation.

Check your understanding

1) What evidence shows that your system was in resonance?

2) How could you adjust your system to change its resonant frequency?

3) Why is it important to record data/observations before presenting?

PS1.10 — Presentations & Quiz

Last lesson you completed and tested your resonant systems. Today you will present your projects to the class, explain how resonance is demonstrated, and take a short end-of-unit quiz to consolidate your learning.

Objectives

Presentation expectations

  • Show your completed system and briefly demonstrate resonance.
  • Explain the science: where are the nodes/antinodes, what is the natural frequency, how is resonance identified?
  • Keep your presentation clear and concise (2–3 minutes per group).

Activity — Group presentations and quiz

Apparatus and materials

  • Completed project models.
  • Quiz sheets (5–10 short questions, mix of calculations and conceptual).
  • Peer-assessment forms or simple rubric (optional).

Procedure (30-minute working window)

  • Groups present in turn (2–3 minutes each). Demonstrate and explain resonance clearly.
  • Audience takes notes or fills peer rubric with one strength + one suggestion per project.
  • After presentations, complete the end-of-unit quiz individually (10–12 minutes).
  • Hand in quiz sheets for marking; brief feedback/discussion if time allows.

Safety

  • Supervise demonstrations (strings under tension, glass, etc.) as in previous lessons.

Discussion prompts

Summary

  • Projects were presented, demonstrating resonance in varied systems.
  • Peer assessment encouraged reflection on clarity and accuracy of explanations.
  • Quiz provided a final check on understanding of wave properties, interference, standing waves and resonance.

Check your understanding

1) State one similarity between resonance in a musical instrument and resonance in an engineering structure.

2) Why does a system oscillate with large amplitude when driven at its natural frequency?

3) Which part of this unit did you find most surprising or interesting, and why?

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