======Speed of Sound with a Resonance Tube======


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**Alternative titles:** Tuning Fork Resonance Tube
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====Summary====                   
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====Procedure====  
  - Set up a vertical resonance tube with its lower end submerged in a water reservoir so the air column length can be adjusted smoothly; ensure the tube can slide freely and remains upright.
  - Choose a tuning fork (for example, 512 Hz). Strike it on a wooden block and hold it horizontally just above the tube mouth.
  - Slowly slide the tube to locate the loudest sound (first resonance, approximately quarter wavelength); clamp and measure the air-column length l1 from water level to tube top.
  - Lengthen the air column to just below about three times l1, then slide to find the next loud maximum (third-harmonic resonance, near three-quarters wavelength); clamp and measure the air-column length l2.
  - Repeat the two-resonance measurements for several forks (for example, 512, 480, 426, 384, 341, 320, 288, 256 Hz), recording f, l1, and l2 for each.
  - For each fork, compute the wavelength using lambda = 2(l2 − l1). Taking the difference largely cancels the end correction.
  - Compute the speed of sound for each fork with c = f * lambda, then average the results.
  - Single-resonance alternative: measure the tube’s internal diameter d (vernier calipers), find the first resonance length l1, apply the end correction e = 0.3 d, then use lambda = 4(l1 + e) and c = f * lambda; repeat across forks and average.





====Links==== 
Finding the Speed Of Sound with a Tuning Fork HD - Physics Walker: 
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Speed of Sound Lab - The Physics Channel with Kenny Lee: 
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📄 MEASUREMENT OF THE SPEED OF SOUND IN AIR - ucc.ie: [[https://www.ucc.ie/en/media/academic/physics/physicsmainwebsite/outreach/experimentdocuments/leavingcertwrite-ups/MEASUREMENTOFTHESPEEDOFSOUNDINAIR.pdf]]\\


====Variations====
  * Replace the fork with a signal generator and small loudspeaker above the tube; sweep frequency at fixed l to find resonance, or fix f and vary l.
  * Use a sliding-piston resonometer or a snug-fitting plunger in PVC pipe to adjust air-column length precisely.
  * Investigate temperature effects.
  * Test humidity influence by repeating on a dry vs humid day, noting any systematic shifts in c.
  * Plot c from each fork versus f to check for frequency-independent results (consistency check).




====Safety Precautions====
  * Secure the tall stand and clamp; prevent the tube from slipping and the water cylinder from tipping.
  * Manage spills promptly; keep water away from electrical equipment and walkways.
  * Strike tuning forks on wood or rubber only; keep fingers clear of vibrating prongs and the tube rim.
  * Keep sound levels reasonable when using a loudspeaker; protect hearing as needed.
  * Handle glass or plastic tubes and calipers carefully to avoid chips, cuts, or pinches.




====Questions to Consider====
  * Why use two resonances (l1 and l2) with the same fork? (Using lambda = 2(l2 − l1) cancels most end-correction error, improving accuracy.)
  * What is the purpose of the end correction e = 0.3 d? (The displacement antinode forms slightly above the tube mouth, so the effective acoustic length exceeds the geometric length.)
  * If f = 512 Hz, l1 = 0.162 m, and l2 = 0.487 m, what is c? (lambda = 2(0.487 − 0.162) = 0.65 m; c = 512 * 0.65 ≈ 333 m s−1.)
  * How will a warmer lab affect your result? (Warmer air increases c; roughly +0.6 m s−1 per degree Celsius.)
  * What are likely sources of random and systematic error here? (Random: reading lengths, locating maxima, fork decay; Systematic: misreading the water level, not centering the fork, ignoring end correction, parallax.)