Why do old springs lose bounce?
Show answer & explanation
Answer: Repeated stress causes fatigue
Metal becomes brittle over time — Wrong. Metal doesn't become brittle from use (unless extreme heat). Springs lose bounce from plastic deformation—repeated stress exceeds elastic limit.
Repeated stress causes fatigue ✓ — Correct! Metal fatigue! Springs work through elastic deformation—compress/extend, return to original shape. Elastic limit: maximum stress before permanent deformation. Repeated cycles gradually exceed limit—microscopic plastic deformation accumulates. Spring permanently deformed—loses 'springiness'. Same principle: bending paperclip back/forth breaks it—metal fatigue. Quality springs (better alloys, heat treatment) resist fatigue longer. Mattress springs weaken over years!
Springs naturally unwind — Wrong. Coil springs don't 'unwind'. They lose bounce from metal fatigue—repeated stress causes permanent deformation reducing elasticity.
More Physics in Daily Life questions
- In a warm office that already reads 26 C, which change can make people feel cooler without lowering the thermostat?
- Why might 26 C feel acceptable in a breezy naturally ventilated summer building but too warm in a sealed winter office?
- On a warm humid day, why can the same 27 C room feel much worse once you start sweating?
- Why can moving air make a 27 C room feel cooler without changing the thermometer?
- Which hidden factor can make a desk beside a cold window feel chilly even when the thermostat across the room still reads 22 C?
- In the same 22 C room, why might someone who just climbed stairs feel warm while someone sitting in a T-shirt feels chilly?