FossWeb offers three sites with interactive inquiry-based science activities. The site does not have full auditory support, but downloadable audio versions of the Foss texts are available. Each level offers a different range of features and topics, but all three offer extensive parent and teacher support.

• The K-2 site includes background information, an interactive activity, related photos, web links, questions answered by professional scientists for units on insects, animals, wood and paper, fabric, trees, balance and motion, pebbles, sand and silt, new plants, air and weather, and solids and liquids
• The 3rd-6th grade site includes interactive activities, posters, pictures and movies, links, vocabulary, book lists and ‘ask a scientist for topics such as magnets and electricity, models and design, the human body, levers and pulleys, food and nutrition, earth materials, water, mixtures and solutions, measurement, physics of sound, solar energy, land forms, structures of life, variables, ideas and inventions, and environments
• The Middle School Site includes multimedia modules, books, links and a glossary covering activities such as human brain and senses, populations and ecosystems, force and motion, planetary science, electronics, earth history, diversity of life, weather and water, and chemical interactions