#  Interference, Refraction & Diffraction 

 



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### Sound Cancellation

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The sound from two speakers destructively interferes.

### Double Sound Source Interference

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Young's experiment performed with coherent sound waves from two loudspeakers.

\[[In-Depth Description](/presentations/double-sound-source-interference)\]

### Beats

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Two tuning forks with similar frequencies; one fork is variable in frequency to tune beating.  
  
\[[In-Depth Description](/presentations/beats)\]

**SEE ALSO**Ripple Tank Applet (select Setup:Two Sources and *2 Src, 2 Freq* from the drop-down menus)### Mechanical Beating

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Shadow projection of the superposition of two circular motions exhibits beating phenomenon.

### Double-source Interference

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Stationary spatial interference pattern from two point sources is displayed on OHP.

### Comb Interference

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Spatial beats between two combs on OHP.

### Ripple Tank Wave Phenomena

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Interference patterns of water waves generated by different sources at adjustable frequency.  
  
\[[In-Depth Description](/presentations/ripple-tank-wave-phenomena)\]

**SEE ALSO**Ripple Tank simulation### Lissajous Figures

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Summation of sinusoidal waves on oscilloscope in x-y mode.

### Contact Us

**Mailing Address**: Lecture Demonstration Services, Science Center, Rm B-08A, 1 Oxford Street, Cambridge, MA 02138  
**Campus Location**: Science Center B-08A | **Tel**: (617) 495-5824 | **Email**: scidemos-at-fas.harvard.edu