| 16.4 Turbulent Centuries in Africa | 9 | March 25, 2012 |
| 25.2 The Earh-Moon System | 10 | March 13, 2012 |
| 26.1 The Sun | 10 | March 6, 2012 |
| 14.3 The Protestant Reformation | 4 | March 5, 2012 |
| 25.5 The Origen Of The Solar System | 4 | February 28, 2012 |
| 25.4 The Outer Solar System | 4 | February 28, 2012 |
| 25.3 The Inner Solar System | 3 | February 28, 2012 |
| 14.2 The Renaissance Moves North | 3 | February 26, 2012 |
| 14.1 The Renaissance in Italy | 11 | February 6, 2012 |
| 12.1 Forces | 12 | February 4, 2012 |
| 11.3 Acceleration | 5 | January 24, 2012 |
| 11.2 Speed and Velocity | 4 | January 18, 2012 |
| 11.1 Distance and Displacement | 5 | January 18, 2012 |
| 9.1 Growth of Royal Power in England and France | 8 | January 9, 2012 |
| 26.3 Life Cycles of Stars | 7 | January 5, 2012 |
| 26.2 Stars | 11 | January 5, 2012 |
| 26.4 Groups of Stars | 10 | December 21, 2011 |
| 26.5 The Expanding Universe | 4 | December 15, 2011 |
| 8.3 The Medievel Church | 15 | December 8, 2011 |
| 8.2 Feudalism and the Manor Economy | 10 | December 6, 2011 |
| 8.1 The Early Middle Ages | 10 | December 5, 2011 |
| 17.2 Properties of Mechanical Waves | 6 | November 29, 2011 |
| 10.1 The Byzantine Empire | 8 | November 28, 2011 |
| 17.1 Mechanical Waves | 9 | November 28, 2011 |
| Islam vocab | 35 | November 15, 2011 |
| 3.3 Phase Changes | 11 | November 7, 2011 |
| 3.1 Solids, Liquids, and Gases | 4 | November 7, 2011 |
| 2.1 Classifying Matter | 9 | October 24, 2011 |
| 5.2 The Modern Periodic Table | 8 | October 19, 2011 |
| 4.1 Studying Atoms & 5.1 Organizing the Elements | 2 | October 19, 2011 |
| 4.2 The Structure of an Atom | 6 | October 19, 2011 |
| 13.5 Japan's Feudal Age | 7 | October 16, 2011 |
| 13.4 The Emergence of Japan | 4 | October 13, 2011 |
| 13.3 Korea and Its Traditions | 3 | October 4, 2011 |
| 13.1 Two Golden Ages of China | 5 | September 27, 2011 |
| 1.3 Measurement | 10 | September 22, 2011 |
| 4.5 Strong Rulers Unite China | 4 | September 21, 2011 |
| 1.2 Using a Scientific Approach | 9 | September 10, 2011 |
| 1.1 What Is Science? | 7 | September 10, 2011 |