======Rubber Band Stretch======


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**Alternative titles:** Rubber Band Thermoelasticity
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====Summary====                   
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====Procedure====  
  -Hold a thick rubber band near your upper lip (skin under the nose is sensitive to small temperature changes) to sense its initial temperature.
  -Quickly stretch the rubber band to 2–3 times its length and immediately place it just below the nose without touching the nostrils to feel the warmth.
  -Keep the rubber band held at that stretch for about 20–30 seconds so it re-equilibrates to room temperature while still stretched.
  -Release the tension quickly and place the relaxed band just below the nose again; you should feel a brief cooling.
  -Repeat once or twice to confirm the effect. Compare quick versus slow stretching to note how rate influences the temperature change.
  -Optional measurement: use an IR thermometer or a taped-on fine thermocouple to record the temperature spike on rapid stretch and the drop on rapid release.



====Links==== 
  * None available

====Variations====
  *Compare different polymers (latex rubber band vs thick exercise band vs silicone band) for size of effect at the same stretch ratio.
  *Hold at different stretch ratios (e.g., 150 percent vs 250 percent length) and record how the temperature change varies.
  *Test rate effects: very fast stretch and release versus slow, steady changes.
  *Map temperature with an IR camera if available, or place a tiny piece of thermochromic paper against the band.



====Safety Precautions====
  *Keep rubber bands away from eyes and face; do not snap against skin. Safety glasses are recommended.
  *Do not overstretch; stay within 2–3 times the original length to reduce breakage risk.
  *Be aware of latex allergies; provide non-latex alternatives if needed.
  *Discard cracked or dried-out bands that may break unexpectedly.
  *Clean or replace bands between participants to maintain hygiene.




====Questions to Consider====
  *Why does the band feel warm when stretched quickly? (Rapid stretching aligns polymer chains, reducing entropy; the material releases heat to the surroundings.)
  *Why does the band feel cool when released after equilibrating? (Rapid contraction increases entropy; the material absorbs heat from nearby air/skin, creating a brief cooling.)
  *Why is the effect stronger when the stretch or release is fast? (Fast changes are closer to adiabatic, limiting heat exchange with the environment, so the temperature change is larger.)
  *How would slow stretching and slow release feel? (Little or no temperature change because heat has time to flow to or from the surroundings.)
  *What variables should you keep constant to compare trials fairly? (Initial band, stretch ratio, hold time before release, ambient temperature, and measurement position.)