When you tap an object you can hear how hard it is, whether it is hollow and what it is made of. If you scratch or scrape it you can hear how rough it is, how bumpy, whether it has a regular texture. However most haptic objects don’t make a sound when you handle them. It’s as though you are in outer space.

Castle G.  Adcock M and Barrass S. (2002) Integrated Modal and Granular Synthesis of Haptic Tapping and Scratching Sounds, in Proceedings of the Eurohaptics 2002 conference (2002).



Close-up view of Haptic Workbench, showing the robotic arm, frame holding the monitor, and an edge-on view of the mirror. This small-scale hands-in virtual environment system was developed by CSIRO researchers. The system has co-located haptic and visual displays.
Haptic Workbench