He-3 The Thermobile

Aim

To demonstrate the conversion of thermal energy into mechanical energy using a shape memory alloy (Nitinol).

Apparatus

  • Thermobile
  • Beaker of hot water

Thermobile 1 Thermobile 2Thermobile Diagram

Thermobile Apparatus and Diagram.

Description

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 (ideally 80°C) whereupon the alloy is raised above Tc and rotation follows.

Video