Science

General Science

• Khan Academy (over 3,000 videos in science and math)

Astronomy

• Atlas of the Universe
• Solar System Views

Chemistry

• Chemicals in the Environment (Chemical Fact Sheets)
• Periodic Table of Elements

Converters

• Currency Converter
• Inflation Calculator (from 1913-present)
• Metric Conversions
• Online Conversions (various conversions)
• Conversion Tables (various conversions)
• XE - Universal Currency Converter

Minerals

• Minerals by Name

Physics

• Physics World (Institute of Physics)

Weather

• Earthquakes (U.S. Geological Survey)
• El Nino
• Volcanoes
• Weather Records & Averages
• World Weather

Zoology/Animal Kingdom

• Animal Diversity Web