Wave Phenomena Diagram – Reflection to Interference

All 12 parts on the diagram

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Which behavior? 4

Reflection The wave bounces off a barrier. It leaves at the same angle it arrived at.
Refraction The wave changes direction as its speed changes. In shallow water it slows, so the wavefronts crowd together.
Diffraction The wave spreads out beyond a gap. The narrower the gap, the more the wave spreads.
Interference Two waves cross and combine. They add in some places and cancel in others.

Reflection and refraction 5

Incident wave The wave on its way to the barrier. The arrow shows which way it travels.
Reflected wave The wave after it bounces off the barrier. Its angle to the barrier equals that of the incident wave.
Barrier A straight bar that the wave cannot pass. In a ripple tank it is a bar laid in the water.
Boundary The line where deep water meets shallow water. The wavefronts stay joined across it, so the wave turns.
Refracted wave The wave in the shallow water. It is slower there, with a shorter wavelength and a new direction.

Diffraction and interference 3

Gap The opening the wave passes through. Beyond it the wavefronts spread out in half circles.
Constructive interference A crest meets a crest and the waves add. The round marks sit where two solid circles cross.
Destructive interference A crest meets a trough and the waves cancel. The square marks sit where a solid circle crosses a dashed one.

How this list was compiled: Every name checked on 2026-10-03 against Wikipedia, text only: Ripple tank, Reflection (physics), Refraction, Snell's law, Diffraction and Wave interference; Georgia State University, HyperPhysics: Reflection of Sound, Refraction of Sound, Diffraction of Sound and Interference of Sound (http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/reflec.html, refrac.html, diffrac.html, interf.html); NASA Science, Tour of the Electromagnetic Spectrum: Wave Behaviors (https://science.nasa.gov/ems/03_behaviors/); a physics tutorial lesson on reflection, refraction and diffraction in a ripple tank (https://www.physicsclassroom.com/class/waves/Lesson-3/Reflection,-Refraction,-and-Diffraction); Penn State University: Refraction of Sound Waves (https://www.acs.psu.edu/drussell/Demos/refract/refract.html); the NDE Education Resource Center: Refraction and Snell's Law (https://www.nde-ed.org/Physics/Waves/refractionsnells.xhtml); and a school physics resource page on diffraction (https://www.schoolphysics.co.uk/age14-16/Wave%20properties/text/Diffraction_/index.html). Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry; nothing traced and nothing animated. Licence: own work

How it works

This wave phenomena diagram shows four things a wave can do, as still pictures of a ripple tank seen from above. Nothing moves. Name the lit picture, or the lit part inside one.

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Telling the four apart

Each line is a wavefront, the crest of one ripple. In reflection the wavefronts meet a barrier and leave at the same angle. In refraction they cross into shallow water, turn and crowd together. In diffraction they spread out beyond a gap. In interference two sets of circles cross.

Inside the pictures

The other two drawings show the same pictures larger. Round marks show where two crests meet and the waves add. Square marks show where a crest meets a trough and the waves cancel.

In the large interference picture the solid circles are crests and the dashed circles are troughs.

Questions and answers

What wave phenomena does a ripple tank show?

Reflection, refraction, diffraction and interference. A ripple tank is a shallow water tank of glass, lit so that the ripples show as shadows, and each behavior can be set up in it.

What is the difference between refraction and diffraction?

Refraction is a change of direction when the speed of a wave changes, as when water waves pass into shallow water. Diffraction is the spreading of a wave beyond a gap or around an obstacle.

What is the difference between constructive and destructive interference?

In constructive interference a crest meets a crest and the amplitudes add. In destructive interference a crest meets a trough, so the combined wave is smaller or cancels.

Can I practice here for “label each animation with the wave phenomenon it best illustrates.”?

Yes, for practice. That sentence is the instruction of a labeling exercise with moving pictures. The pictures here are still drawings of our own, so you tell each behavior from the shape of its wavefronts.