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Energy stored in a rubber band

When a rubber band is stretched it gets slightly warmer. This is because there is friction between the untangling molecules.

If you stretch a rubber band and record the extension against load and carefully take the load off again still recording the extension you can plot a graph of extension against load.

To work out the energy of each section you find the area under the line.

The rubber band will often be left with a small extension even after the load is removed.

© Keith Gibbs 2009