Definition:
Rubber, in its natural state, is a yellow, amorphous, elastic material that is obtained from the milky sap (also known as latex) of various tropical plants, most notably the rubber tree. This rubber is then vulcanized (treated with heat and sulphur), pigmented (given color artificially), finished and modified into products such as tires and electric insulation. Rubber, whether natural or synthetic, has many properties that make it unique. One of the most well-known properties, rubber's uncanny ability to stretch and to reform into its original shape, is best seen in rubber bands.
Entropy:
The main thing to remember when discussing rubber bands is entropy. Generally speaking, entropy is chaos, or a lack of order. Entropy is best defined in the Second Law of Thermodynamics, which states that a system will naturally move from a state of order to a state of disorder. This is best illustrated in a rubber band. While not being stretched out, the polymers (molecules that make up the rubber) are tangled up in a random mess, all of them haphazardly lying atop the others. When a rubber band is stretched, though, these molecules lengthen out and become ordered in a single direction. However, the natural urge is to return to the state of entropy, so as soon as the rubber band is released, it will snap back to its original form and back to a state of entropy.
Heat:
One interesting thing that a person can do to test this theory is to take a rubber band and stretch it out. Once the rubber band is stretched, press it against the skin of the face. The rubber band will feel warm. Once it's let go and pressed back against the face, it should feel cold. When a rubber band is stretched out far, the molecules may become perfectly aligned and form crystals (extremely ordered molecule alignments). Crystals naturally give off heat, so the rubber band will feel quite warm when in this state. Allow it to snap back, breaking the crystal alignment, it will absorb heat to do so. The heat goes into breaking the alignment, so when you touch the rubber band again, it feels cool.
Rubber, in its natural state, is a yellow, amorphous, elastic material that is obtained from the milky sap (also known as latex) of various tropical plants, most notably the rubber tree. This rubber is then vulcanized (treated with heat and sulphur), pigmented (given color artificially), finished and modified into products such as tires and electric insulation. Rubber, whether natural or synthetic, has many properties that make it unique. One of the most well-known properties, rubber's uncanny ability to stretch and to reform into its original shape, is best seen in rubber bands.
Entropy:
The main thing to remember when discussing rubber bands is entropy. Generally speaking, entropy is chaos, or a lack of order. Entropy is best defined in the Second Law of Thermodynamics, which states that a system will naturally move from a state of order to a state of disorder. This is best illustrated in a rubber band. While not being stretched out, the polymers (molecules that make up the rubber) are tangled up in a random mess, all of them haphazardly lying atop the others. When a rubber band is stretched, though, these molecules lengthen out and become ordered in a single direction. However, the natural urge is to return to the state of entropy, so as soon as the rubber band is released, it will snap back to its original form and back to a state of entropy.
Heat:
One interesting thing that a person can do to test this theory is to take a rubber band and stretch it out. Once the rubber band is stretched, press it against the skin of the face. The rubber band will feel warm. Once it's let go and pressed back against the face, it should feel cold. When a rubber band is stretched out far, the molecules may become perfectly aligned and form crystals (extremely ordered molecule alignments). Crystals naturally give off heat, so the rubber band will feel quite warm when in this state. Allow it to snap back, breaking the crystal alignment, it will absorb heat to do so. The heat goes into breaking the alignment, so when you touch the rubber band again, it feels cool.