PhysicsUK

RIPPLE TANK & WAVEFRONT LAB Investigation 01

Measure a progressive wave

Use several wavefront spacings to find wavelength, then test the wave equation.

0.00 s
EXPERIMENT BENCHTop view · 120 × 72 cmPaused
Interactive top-down ripple tank.
+ crest0 rest− trough

Run the waves, pause a pattern, then measure it.

0 items

Ready to investigate

Choose an experiment

Every starting point is editable. Setups stay available as you switch investigations.

Your current setup and captured readings recover on this device. Saved files restart waves; live fields and traces are not saved.

Add apparatus

Click a part, then move it on the tank. Up to 14 items.

Experiment controls

Wave driver

Nothing selected

Add apparatus or select it in the tank to reveal precise controls.

Explain the physics

MODEL PREDICTIONS & EXPLANATIONS

Reveal the physics

Model values for the surrounding water.

Frequency, f
2.00 Hz
Expected period, T
0.500 s
Model speed, v
24.0 cm s⁻¹
Model wavelength, λ
12.0 cm
Wave equation v = fλ

What to notice

Wavefronts join points at the same phase. The wave travels at right angles to them; the water itself oscillates locally.

Discuss it

Increase frequency without changing depth. Which quantity must change, and which stays constant?

Key terms

Key terms in this scene

Core
Practical & teacher lens

Freeze the pattern and measure across several wavelengths. In a real tank, reflections, parallax and broad crests all add uncertainty.

What the model represents

Colour is vertical displacement, not depth. This is an idealised two-dimensional wave model: real ripple tanks also show viscosity, dispersion and imperfect boundaries.

Experiment notebook

Captures retain your ruler placement, counted gaps, sampled period and original apparatus. Unavailable measurements stay blank. Align matching crests before capturing.

Measured wavelength against inverse frequency

Capture at least three different frequencies with the same depth and apparatus.

The latest capture selects the series. Its depth, source and wave-altering apparatus must match. Ruler and probe positions may change. A gradient estimates speed only for comparable progressive-wave measurements.

Readingf / Hzλ / cmT / sTimer / sSetup

A LITTLE HELP GETTING STARTED

Make a wave. Follow its story.

  1. Choose an investigation. Each topic opens an editable experiment. Switching topics keeps your setup in this tab.
  2. Run and pause. Watch the pattern develop. Step advances the frozen field; Restart waves clears it while keeping the apparatus.
  3. Build your experiment. Click a part to add it. Drag it in the tank, or open Controls for exact positions, sizes and angles. Undo and redo recover setup changes.
  4. Measure it yourself. Choose Ruler, pause the waves and place A and B on matching crests. Count complete gaps, not crests. The ruler estimate depends on your placement. Choose Probe A to see displacement against time at a point. Click an active instrument again to put it away.
  5. Reveal the physics. Open Explain for model predictions, discussion prompts and key terms. These predicted values are separate from your ruler estimate.

Keyboard: focus the tank, then Tab through its items. Arrow keys move the selected item (Shift for smaller steps); Enter opens Controls. Escape leaves the selection. Space runs or pauses; Ctrl+Z / Ctrl+Y undo and redo. Both ruler endpoints can be chosen in Controls. Tab from the last item leaves the tank.

Double slit: choose investigation 06 for straight wavefronts passing through two gaps, or add a Double gap to any setup. Controls adjusts each gap's width and the centre-to-centre separation. Narrow openings spread the waves so they can overlap and interfere.

The model: green crests and pale mint troughs show positive and negative vertical displacement in relative units; dark green is zero displacement. Colour does not represent water depth. The field includes reflection, diffraction and interference. Direction arrows are guides for the primary source in simple arrangements; overlapping waves can travel in several directions. Real ripple tanks also have viscosity, dispersion and imperfect boundaries.

AQA / OCR · GCSE and A Level waves