Question

Does cold temperature affect the elasticity of a rubber band?

Asked by: Kimberley

Answer

Yes--a rubber band will actually become softer, or easier to stretch, when the temperature gets colder. The way to think of the elasticity is in terms of entropy, which is basically a measure of disorder. The universe is always moving towards a state of greater disorder.

When a rubber band is stretched out, there aren't as many ways the individual molecules can arrange themselves as there are when the rubber band is not stretched. They have to be sort of lined up, instead of in a jumble. There are a lot more ways to throw the molecules into a jumble than there are to line them up.

When there are more ways to arrange the molecules, the entropy is higher. So when you stretch a rubber band, entropy dictates that the rubber band will want to contract again. Where does temperature come in? When the temperature is higher, the molecules are more excited, and want even more to be in a random jumbled state. Think of a class of kindergardners on a sugar high--they'll want to run all over the place, not line up in a straight row. This makes the rubber band harder to stretch out, because it is harder to line up the molecules inside. Hence, it is stiffer at higher temperatures.

Things other than rubber bands can be described by the same entropic theories. They are even being used now in biology, to describe the behavior of DNA when stretched, for example.

There is a brief summary at this website.

Answered by: Danielle Cook, B.S., Bioengineering Graduate Student, MIT, Boston

Search

Loading






Science Quote

'Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover.'

Bertrand Russell
(1872-1970)
Science Sidebar | Science Education Articles
10 Ways to Keep Your Kids Interested In Science

Young children are natural scientists: they ask questions, pick up sticks and bugs outside, and are curious about the world around them. But as they get a bit older, many kids gradually lose their interest in science. They might see it as just another task at school, something that doesn't apply to their lives. Of course nothing could be further from the truth, so here are ten ways you can remind your kids that science is everywhere. Most of these are fun for adults, too! Continue reading ...

Top Selling

Here are our physics & astronomy bestsellers:
Magnetic Levitator - Classic
12 inch Galileo Thermometer
Solar Radiometer
Weather Station 4M Kit
Cricket, Locust, Beetle and Crab
3D Magnetic Field Tube
Clean Water Science 4M Kit
Revolving Multi-Color Fiberoptic Light
Space Wonder Gyroscope
Mini Plasma Ball

Sponsors

USC University of Southern California Dornsife College Physics and Astronomy Department McMaster University Physics and Astronomy Department