With Virtual Labs, imagination is the limit, in every sense. Virtual Labs: Electricity and Virtual Labs: Light both provide blank workbenches for students to tinker with. Students can then design an infinite number of experiments. When a teacher is running the show, giving assignments, and checking work, Virtual Labs is a powerful teaching aide. However, the program offers little help in getting started, so students probably won't be tempted to embark on experiments on their own.
Structurally, the Light and Electricity versions are very similar to one another. Each contains a workbench with a variety of parts that you can add and move around. The Light workbench contains lights, color filters, and mirrors, while the Electricity workbench contains batteries, resistors, and lights and bells (to indicate whether your circuitry works). Both programs come with a few dozen models to start with. Some illustrate a concept while others pose a problem for the student to solve.
The lab software has a Sci-Clopedia section that contains some brief definitions of vocabulary words. As a bonus, the CD-ROM includes the World Book Bonus Science Reference, a subset of the World Book Encyclopedia. It's a rich reference tool composed of 98 articles.
Each set includes two copies of the Lab CD-ROM, and a binder full of assignments and instructions for the teacher.