Fig. 1. The micro-beam tensile test apparatus used to measure the thermoelastic properties of spider silks. A supercontracted silk thread (green line) is mounted between a glass beam and a moveable micrometer mount. A video dimension analyzer (VDA) system mounted on a microscope is used to track the deflection of a glass micro-beam relative to a reference glass beam. This provides nano-Newton resolution of changes in the elastic force. A thermistor placed near the silk sample measures temperature.