# Learner lab record: Standing-wave mode record

Course: Waves, resonance, and spectra

Name: ____________________  Date: ____________________  Group: ____________________

## Investigation question

How do boundary length, wave speed, and integer mode number determine nodes, wavelength, and frequency?

## Setup

Use the standing-wave atelier. Keep two inputs fixed while changing the third, and record the driver-energy statement separately from the mode geometry.

## Variables

| Variable | Role | Unit |
| --- | --- | --- |
| Boundary length L | independent | m |
| Mode number n | independent | integer |
| Wave speed v | independent | m/s |
| Wavelength and frequency | dependent | m and Hz |

## Predict before changing controls

1. Predict how doubling n changes wavelength.

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2. Predict how changing speed affects node positions.

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## Observation table

| L | n | v | wavelength | frequency | node count |
| --- | --- | --- | --- | --- | --- |
|   |   |   |   |   |   |
|   |   |   |   |   |   |
|   |   |   |   |   |   |
|   |   |   |   |   |   |
|   |   |   |   |   |   |
|   |   |   |   |   |   |

## Analyze

1. Which runs isolate mode number?

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2. Which quantity changed without moving the nodes?

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3. What supplies energy to a real resonator?

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4. Write one proportional relationship supported by your table.

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## Evidence-bounded conclusion

For fixed ___, increasing ___ by a factor of ___ changed ___ by a factor of ___.

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