PBS
Pbs Learning Media: Balloon Car
Make 4-wheeled, air-powered cars that jet across the floor. Experiment with the design process and thrust in this activity from Design Squad Nation.
Other
Paper Plate Education: Serving the Universe on a Paper Plate
Excellent resource for "paper-plate" activities that help simplify various astronomy topics. Learn how to build a "Moon Finder" and "Planet Pointer," and create a paper-plate model that explains the Transit of Venus.
Science Fun for Everyone
Science Fun: Super Cool Soda
Cook up a slushy soda treat with this hands-on experiment. Links to video of experiment.
Other
Staten Island Children's Museum: Great Explorations: All About Rainforests [Pdf]
Use this guide and your imagination to take a trip to the rainforest.