He-3 The Thermobile
Published: Monday 13 March 2006 - Updated: Monday 28 March 2011
To demonstrate the conversion of thermal energy into mechanical energy using a shape memory alloy (Nitinol).
- Beaker of hot water
Click on pictures to enlarge.
The thermobile consists of a shape memory alloy Nitinol (Nickel-Titanium). Above a temperature Tc this alloy returns to an earlier shape given to it previously by appropriate heat treatment. The alloy absorbs heat as it returns to this shape converting it into mechanical work.
The demonstration consists simply of dipping the small metal wheel of the thermobile into hot water whereupon the alloy is raised above Tc and rotation follows.