Automatic engine

The power of the exhibit "Automatic Engine" comes from the unique response of shape memory alloy to temperature. When the alloy wire is immersed in hot water, it contracts like a muscle and generates torque, thereby driving the wheel to rotate; Once it returns to room temperature, it relaxes and recovers. It is precisely by utilizing the temperature difference between hot water and room temperature that the alloy wire can continuously undergo a cycle of "heating shrinkage cooling relaxation", converting thermal energy into mechanical energy and achieving automatic operation of the wheel.

The unit is designed for unsupervised public use: controls are recessed or shielded, moving parts are enclosed, and the interface is operable by a child of about six with no instruction. Where a screen is used, the language can be switched without changing the hardware, and the content can be replaced on site.

(1) Scientific principle: When the alloy wire is immersed in hot water, the crystal structure of the alloy wire will change from martensitic phase to austenitic phase. Due to the stable structure of the austenite phase, it is not easily deformed. So at this point, the heated alloy wire will have super elasticity and a tendency to straighten, causing tension underneath. The entire device will generate a torque and then rotate. More alloys were immediately pulled into the water and tightened, then cooled and relaxed at the top, and thus began to circulate. (2) Superelasticity is a material property that refers to the phenomenon where certain alloys can undergo significant deformation under external forces, and can fully recover to their original shape and size after removing the external forces.