Hey Ray! Rubber Band Heat & Entropy

made in usa
made in usa

We love finding videos that share the same enthusiasm about rubber bands that we have! Check out this new video posted from “Hey Ray!” Meteorologist Ray Petelin.

Sometimes the most seemingly simple things in your house end up being the most complicated. Take, for example, rubber bands (or gum bands as we call them around our house). These everyday household items have been in junk drawers and even office supply closets for nearly 200 years.

Not only does the rubber band feel warmer when you stretch it, it actually heats up. You can see this in action with a thermal imaging camera. As the rubber band is stretched, it heats up, and when you let it go back to its resting position it literally cools down.  What is happening is a thing called “entropy.”

ENTROPY: A thermodynamic quantity representing the unavailability of a system’s thermal energy for conversion into mechanical work.

What does that mean? The polymers or chains of molecules that make up the rubber bands look like an entangled pile of rubber bands or even a plate of spaghetti when they’re in their resting state. This is where they have a higher entropy (a higher amount of energy that is not available) to do work. This is how a rubber band naturally wants to be.  When you stretch them, the rubber band’s polymers stretch into ordered chains because work is obtained from ordered molecular motion. Since we’re doing the work to stretch the rubber band and put those polymers in order we are adding energy to the rubber band. That extra energy causes the molecules to move more rapidly – giving off heat.

How do you know it’s not just your body heat warming up the rubber bands? Scientifically, the opposite should be true if you let the rubber bands polymers (or molecules) go back to their higher entropy state or become un-stretched they should absorb that heat and become cooler. This is something that we can see with the thermal imaging camera and feel with our skin. And you’ll notice that we did use glasses since we’re using rubber bands close to our face. Remember, always protect your eyes and always use a clean rubber band that’s very important!


Alliance Rubber Company is a family-owned business with humble beginnings that has grown into a thriving American success story. Since 1923, Alliance Rubber has proudly produced rubber bands for use in the home and workplace. Continuing to manufacture its products in the USA enables Alliance to provide high-quality products, fast service, and fresh stock that is built to last. Alliance Rubber, a women-owned company, manufactures bands that ‘Hold Your World Together.’

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