I conducted an experiment for a physics lab and noticed that the warmer the elastic band was, the further it would stretch when I place the same mass on it. I’ve been told this is because of the glass-transition effect, thoughts?
In: Chemistry
They usually don’t. Warm rubber bands have more tension than cold rubber bands!
Do the experiment! Dangle something from one, then heat it up. It’ll contract. This is because elasticity comes from the randon jiggling of long chain elastomers. More heat means more jiggling and more pulling.
Well don’t trust me on this but warmth can cause molecules to become loser and less attached to each other which makes them easier to pull.
It’s the other way around. Using the thermodynamics definition of entropy, dS = d(q_rev)/T, where S is entropy, q_rev is reversible heat flow, and T is temperature.
dS relates to stretching in that when the rubber band is stretched, the molecules have fewer configurations they can be in, so dS goes down. For a big T (i.e. heated rubber band), the dS is less than that of a small T (cold rubber band). In other words, a hot rubber band stretches less than a cold one.
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