This is a simple but fascinating demonstration of Muscle Wire® material technology. It looks like a regular spring. Pull it out and it snaps back. It has superelastic properties, so you can pull it out a really long way and it will snap back.

If you pull it out a long way- enough so if it were a normal spring, it would be overstretched and permanently distorted, and hold it for about five seconds, it looks any spring would look if it had been overstretched. But this is a shape memory alloy, and we have set the transition temperature to a bit below body temperature. When you hold it in your hands, you warm it up and it goes back to normal.

This is an intriguing little device. It's like a longer version of the Muscle Wires® Impossible Spring™, but it's also been trained. Yes, we can train metal. In this case we train it to "remember" a different shape when it's cold. Looks pretty small and simple, doesn't it?

It's small but it's not simple. We call these the "impossible" products because they do things that appear to be impossible. No, they're not magic. Just clever. This coiled piece of wire violates the following rules about how things behave in the normal world.

• When you overstretch a spring you've spoiled it. It can't be fixed in any reasonable way.
• When you cool off a piece of metal it contracts.
• When you heat up a piece of metal it expands
• Thermally induced changes in a piece of metal of uniform material are too small to see with the naked eye.

Not bad. Four apparent violations of the laws of physics in something you can put into your shirt pocket and forget! Can you explain that? Can your friends?

Click here to see more information, including a video.

Great gift for the student of any age. Smart kids love this, because they know it's something new and different. If you have a smart child or grandchild they've be fascinated!.