======Double Slit Experiment with Water Waves======


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**Alternative titles:** Wave Interference with Two Slits
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====Summary====                   
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====Procedure====  
  - Fill a shallow tank or tray with water and let it settle.  
  - Place a barrier across the tank with two narrow, closely spaced slits.  
  - Generate waves by tapping the water gently with a rod or using a mechanical vibrator in front of the slits.  
  - Observe how the waves spread in circular patterns from each slit.  
  - Watch where the two wavefronts overlap: crests meeting crests form higher waves (constructive interference), while crests meeting troughs cancel out (destructive interference).  
  - To make the pattern clearer, shine a light from above so the interference ripples create a visible pattern on the tank bottom or wall.




====Links==== 
Double slit interference of water waves (NCPQ) - Dr Richard Walding: 
{{youtube>9guiF14NWpY?}}\\

Physics • Double Slit Experiment - Water Wave Interference Pattern - Points in Time: 
{{youtube>Jqm4f55soJQ?}}\\

📄 Double slit experiment - Anton Paar: [[https://wiki.anton-paar.com/au-en/double-slit-experiment/]]\\


====Variations====
  * Try changing the spacing between the two slits and observe how the interference pattern changes.  
  * Use different wave frequencies (faster or slower tapping) to compare the resulting interference fringes.  
  * Compare single-slit versus double-slit setups to highlight the effect of interference.



====Safety Precautions====
  * Keep electrical equipment (lamps, vibrators) safely away from water to avoid shock hazards.  
  * Avoid spilling water onto floors to prevent slipping.  
  * Handle glass or acrylic tanks carefully to prevent breakage.




====Questions to Consider====
  * What happens at points where two crests meet? (The waves add together, making a taller crest.)  
  * What happens where a crest meets a trough? (They cancel, creating a calm spot.)  
  * How does changing slit spacing affect the interference pattern? (Closer slits spread the pattern wider; farther apart narrows it.)  
  * How does this water-wave experiment help us understand light’s behavior in the double slit experiment? (It shows that light, like water, can behave as a wave, producing interference patterns.)