Students were able to construct their own virtual experi-
mental set-ups by simple and direct manipulation of objects,
materials and virtual instruments. The software offered feed-
back throughout the conduct of the experiment by presenting
information (e.g., time, temperature, volume) through the
displays of the software and by animating the phenomenon
(e.g., bubbles and steam come out of solution when water is
boiled). No feedback was provided by the software during the
preparation of the (virtual) experimental set-up. The level of
feedback was analogous to what is routinely available to
students through PME