Interference of two waves in 3D (double slit experiment) – Geogebra

Wave interference 3d (double slit)

Wave interference 3d (double slit)

This simulation dynamically reproduce, in 3D, the “double slit” wave interference.
In the following interactive Geogebra simulation it is possible to set the different wave parameters (through the sliders in the upper part of the window) and it is also possible to drag and move the wave sources (S1 and S2) and the arrival point of the waves (P) on plane to the right.
The interference pattern (constructive interference, destructive interference and all the other possible intermediate results) will be shown on the screen opposite to the wave sources (after the waves reach it).

The Geogebra file can be downloaded and/or viewed in the Geobebra site here,


The waves presented in this simulation behind the screen are just a virtual representation of the history of what happened on the screen.
So it must be kept in mind that the two representations (before and behind the screen) have a very different conceptual meaning. In fact, in the physical actual thought experiment, the screen is supposed to be opaque and there’s no real wave behind it.
Practically, before the screen you can see the progressive waves (moving in space through time), whereas behind the screen the graph represents what has happened in the point P of the screen through time (and not an actual wave).

Things to experiment and open questions:

  • Click on the “play/pause” little button (located to the left, just below the sliders section and above the 3D view) to start/pause the time animation.
  • Click and drag in an empty area to rotate the point of view; shift+click and drag to translate the point of view.
  • Drag the P point to find the positions of full constructive and destructive interference. Alternatively you can also move the wave sources S1 and S2.
  • Try to set different phases (ψ) and amplitudes (A): what are the changes in the total wave?
  • See what happens when the two waves have different wavelengths λ and/or different speed v. You can restore the classical settings (with ψ21, v,2=v1 and λ21) pushing on the button “same ψ, λ, v” (this button appears only when the parameters are not all identical).
  • What is the meaning of the colored area near the wave source when the option “show path difference” is checked? How does this relate with the amplitude of the total wave?

Interference (wave propagation) (

Last edited on March, 8, 2017

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