CK-12 Foundation
Ck 12: Classification of Matter
[Free Registration/Login may be required to access all resource tools.] In this online tutorial students will define a mixture and understand why mixtures are different than pure substances. They will classify mixtures as homogeneous or...
Curated OER
Cornell University: The Phases of the Moon
This site from Cornell University provides great information on the different phases of the moon. As the Moon moves in its orbit around the Sun, our view of the side illuminated by the Sun changes. Furthermore, the rising and setting...