• PhET

    University of Colorado (Physics Education technology)
    Lots of good applets to help you see and experiment with various physics, Earth science and chemistry concepts.
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  • NASA - Global Climate Change

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  • IPCC - Intergovernmental Panel on Climate Change

    The planet's premier scientific climate change organization.  These are the folks who sift through all the major climate data, reports, and then make predictions upon which international policies are discussed and based.
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  • Periodic Table

    Periodic Table showing samples of each element.  (Theodore Gray)
    Includes many practical uses and/or samples for each element (when possible) and an element spelling tool.
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  • Ptable

    Interactive Periodic Table of Elements.  
    Examine properties of elements, bonding ratios, electron structure...
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  • Physics Classroom

    Good tutorials for motion, force and energy.  Includes sample problems with solutions and interactive HTML simulations. 
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