This page introduces 2D interference. If you are looking for the more advanced explanation involving diffraction and double slit interference, go here.
In the previous lesson we looked at super position which lead to an understanding of interference in one dimension.
Waves, and the vast number of cases are two or three dimensional.
This means that when we have a 2D or 3D wave propagating through space, and encounters another wave, we will get interference.
And we will get both constructive, and destructive interference depending on the respective phases of the waves in that moment of space and time.
Interactive
Again, before we examine the theory, we will see this in action let's start by exploring pHET interactive Lab which allows you to explore interference
Waves, and the vast number of cases are two or three dimensional.
This means that when we have a 2D or 3D wave propagating through space, and encounters another wave, we will get interference.
And we will get both constructive, and destructive interference depending on the respective phases of the waves in that moment of space and time.
Interactive
Again, before we examine the theory, we will see this in action let's start by exploring pHET interactive Lab which allows you to explore interference
- Start by clicking the Interference TAB.
- You are presented by two taps (faucets). Start both
- Eventually you will see a series of lines, where there appear to be be no discernible wave front.
- It is at these lines, that the two waves interference in such a way that one is always out of phase with the other - we have destructive interference.
- In between, the waves always add up - constructive interference
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Video
We will now look at two dimensional interference qualitatively, in other words, without the mathematics involved |
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Interactive
The animation below allows you to see not the effect, but the individual wavefronts as they overlap. This allows you to see where the nodal and anti nodal lines develop (from Tom Walsh)
The animation below allows you to see not the effect, but the individual wavefronts as they overlap. This allows you to see where the nodal and anti nodal lines develop (from Tom Walsh)
From the same author, this looks at interferences from a 3D perspective.
