PBS
The Math of Bicycles: Wheel Figure This Out (Grades 4 7)
Several good activities here. Look particularly at Wheel Figure It Out (which is the opening page) and Gearing Up. There are answers to the very good questions at the bottom of each.
Other
Hartao: An Introduction to Plate Tectonics
Introduces South African Alexander Toit as naming Gondwanaland and Laurasia.
Other
Wisconsin State Reading Association (Wsra)
Learn about the goals, membership, publications, and committees of this affiliate of the International Reading Association. Links also take you to useful reading resources and to its hotline, which allows members to be a part of an...
Enchanted Learning
Enchanted Learning: All About Plate Tectonics
Simple discussion of plate tectonics and Pangaea. Includes maps and interactives.
AAA Math
Aaa Math: Subtracting Fractions With Same Denominator
Gives a brief explanation of how to subtract fractions with the same denominator. Gives practice, and games to play to use this skill.