| Atoms and Bonding | 15 | May 7, 2013 |
| Photosynthesis and Respiration | 8 | January 21, 2013 |
| Rocks | 21 | December 18, 2012 |
| Cell Structure and Function | 15 | December 7, 2012 |
| Minerals | 16 | November 8, 2012 |
| Volcanoes | 32 | October 24, 2012 |
| Protists and Fungi | 18 | October 24, 2012 |
| Viruses and Bacteria | 21 | October 11, 2012 |
| Earthquakes | 23 | October 11, 2012 |
| Plate Tectonics | 31 | September 20, 2012 |
| Elements and the Periodic Table | 29 | May 15, 2012 |
| The Circulatory System | 18 | May 10, 2012 |
| Digestive System | 18 | April 30, 2012 |
| Solids, Liquids, and Gases | 22 | April 3, 2012 |
| Muscle and Skin | 13 | April 2, 2012 |
| Skeletal System | 25 | April 2, 2012 |
| Introduction to Matter | 26 | March 6, 2012 |
| Modern Genetics | 14 | March 5, 2012 |
| Geologic Time | 24 | January 30, 2012 |
| Genetics | 20 | January 11, 2012 |
| The Cell Cycle | 6 | January 10, 2012 |