AplusMath 

• Improve your math skills interactively

Ask Dr. Math

Biology Experiments for Kids

Chem4Kids

Constellations and their Stars

Earthquakes for Kids

EarthSky

• Covers many popular science topics

Electronic Zoo

• Links to sites about animals

 Energy Kids

• With the help of "Energy Ant," learn about the world's main energy sources

Engineer Girl

Everyday Mysteries

How To Smile

• Science and Math Activities

Mineral Galleries

NASA Kids' Club

Newton's Apple

Periodic Table

Science Buddies

• Science fair project ideas, answers and tools

Science Links for Kids

• Earth, Life, and Physical Sciences

SEDS: Students for the Exploration and Development of Space

• A group seeking to educate the public in order to attain the goal of expanding the role of human exploration and development of space

 
Volcanoes (Geology for Kids)

Weather (UCAR Center for Science Education)

Weather Wiz Kids

Whale Times

• Also seals, sea lions, sharks, penguins, walruses and more

What Tree Is It?

World of Scientific Biography

• A treasure trove of scientific biography, organized by branch of science, gender, ethnicity, nationality, historic periods and prize winners