Enchanted Learning offers a host of resources and activities for kids up to grade 3. Multilingual picture dictionaries, weather activities, seasonal games, printable books, word wheels, crafts, animal printouts, science projects and K-3 themes are all offered for free at this site. There are lesson plans about plants, explorers, astronomy, whales, art, music and geography. Learn American sign language, study anatomy and complete computer-terms quizzes all on this site.
Scholastic offers a wide selection of interactive activities and free educational materials on their website. Topic areas are language arts, social studies, science and math. Activities for grades 3 through 5 include grammar and punctuation games, science projects, astronomy and weather lessons, math practice, historical stories, interactive research projects and geography and mapping skills. The site also hosts a list of over 700 lesson plans of activities for third-graders.
An excellent source for third grade math materials is the National Library of Virtual Manipulatives, which has dozens of online games covering the topics of number operations, algebra, geometry, measurements and probability. Another math site is CoolMath4Kids, which has online lessons, quizzes and games for third-graders.
Discovery Education has lesson plans in science, technology, social studies, math and language arts. This site also has interactive educational games and homework help. Students can browse through homework help pages for science, English, social studies and math; each subject has a wide selection of videos, interactive resources and online learning activities. The games section has online games such as memory and hangman.
The Smithsonian Institution has online activities and educational resources available for children. Their site includes an educators' section, where teachers can enter the grade level and subject they want materials for into a search engine, and references will appear. There is also a students' section, which offers interactive games and resources in the subjects of art, science, nature, history, culture, people and places.