Jouni equates the stiffening of the spring by the cold bath with the shape changing behaviour of nitinol. However, I think the stiffness of a wire is a property which is independent of the wire's shape. Consider two short lengths of _straight_ wire. One is made from copper and one is made from nitinol. The force required to bend each wire is a measure of each wire's stiffness. Warming or cooling the cooper wire will not cause the cooper wire to bend but it will alter its stiffeness. It may also be possible to forge a straight piece of nitinol wire such that the nitinol wire's stiffness can be changed by warming or cooling without causing it to change shape.
Harry
