| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: show an understanding of experiments that demonstrate stationary waves using microwaves, stretched strings and air columns (it will be assumed that end corrections are negligible; knowledge of the concept of end corrections is not required) |
Learning Objective/s:
- Describe the formation of stationary (standing) waves and identify nodes and antinodes.
- Explain how boundary conditions determine the allowed wavelengths in microwave waveguides, stretched strings, and air‑column tubes.
- Calculate wavelength and frequency from experimental measurements for each of the three setups.
- Compare the three experimental methods and evaluate typical sources of error.
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Materials Needed:
- Microwave transmitter, rectangular waveguide, movable metal reflector, detector probe.
- String apparatus: string, clamps, hanging masses (to set tension), mechanical oscillator or speaker, strobe light.
- Resonance tube (open‑open/closed‑open), speaker, signal generator, microphone, oscilloscope.
- Ruler/measuring tape, calculator, student worksheets.
- Projector and slides for theory review.
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Introduction:
Begin with a short video clip showing a rope forming clear standing‑wave patterns, then ask students to recall what nodes and antinodes are. Link this to their prior learning of wave interference and the equation v = fλ. State that by the end of the lesson they will be able to design and analyse three different experiments that reveal stationary waves.
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Lesson Structure:
- Do‑Now (5 min): Quick quiz on wave superposition and the formula L = nλ/2.
- Mini‑lecture (10 min): Review of standing‑wave theory, nodes/antinode spacing, and boundary conditions for EM, transverse, and longitudinal waves.
- Microwave experiment demonstration (12 min): Set up waveguide, move detector, record maxima/minima, calculate λ and f.
- String experiment stations (15 min): Groups adjust tension, drive the string, identify harmonics with strobe, record frequencies.
- Air‑column experiment (15 min): Use resonance tube with signal generator, locate resonances via microphone/oscilloscope, compare to theoretical values.
- Guided comparison (8 min): Fill a table contrasting wave type, boundary conditions, frequency range, and key equations.
- Check for understanding (5 min): Exit ticket – one sentence summarising why only certain frequencies produce standing waves.
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Conclusion:
Recap that stationary waves arise from interference of two opposite‑traveling waves and that the fixed nodes/antinodes give discrete resonant frequencies. Collect exit tickets and highlight common misconceptions observed. Assign homework: complete a worksheet calculating wavelengths and frequencies for a new set of string and tube lengths.
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