Why rubber bands get shorter when you heat them from the naked scientist rubber band elasticity and temperature from science buddies science activities for all ages.
Why does an elastic band heat up when stretched.
Rubber is made of polymers long chain molecules.
Next if you take a hair dryer and heat the rubber band the heat will cause the polymers to want to coil back up and you can watch the rubber band then shrink and pull the weight back up a little bit.
It can be stretched by up to a factor of 10 from its original length and when released returns very nearly to its original length.
This can be repeated many times with no apparent degradation to the rubber.
When a rubber band is unstretched relaxed state the molecule chains are all twisted up figure 1 a.
If you suddenly stretch the rubber band and immediately press it against your upper lip you ll feel that it s got hot heat energy has been given out.
The appropriate fix depends on how much extra room you need.
Stretching a rubber band.
It is a polymer that means that the rubber molecules are made of long chains of atoms.
Rubber has some strange elastic properties.
Rubber is a member of a larger class of materials called elastomers and it is difficult to overestimate their economic and.
When a rubber band is in its stretched form those same polymers will unwind and become straight.
Rubber elasticity refers to a property of crosslinked rubber.
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Elastic can be stretched in several ways.
When a rubber band is in its relaxed form meaning that it isn t being stretched these long chain molecules are tangled up with one another.
As the rubber is stretched they begin to untangle themselves as shown in figure 1 b.
When the elastic band is not stretched these molecules are all tangled up with each other and have no particular direction to them but when you stretch the elastic they all become lined up with one another at least to some.
From science buddies.
The key lies in the reason for the stretchiness of the rubber band.
When a rubber band is taut its color will often change to a lighter shade even white.
More impressive is when you let the rubber band back to its normal length you ll feel the rubber band go amazingly cool against your skin as it sucks up heat from you.
Learn what elastic potential energy means and how to calculate it.
The properties that make an elastic band a useful item can also be annoying when the elastic is too tight.