- Butterflies of the United States and Canada
- Forces of nature
- New year celebrations
- Heat waves
- The World Book encyclopedia, 2009, v. 15
- The World Book encyclopedia, 2009, v. 8
- The Inca
- Amphibians
- Medicine
- Volcanoes
- The circulatory system
- Hurricanes, typhoons, & other tropical cyclones
- Insects and spiders
- The World Book encyclopedia, 2009, v. 20
- The World Book encyclopedia, 2009, v. 16
- Birds, World Book
- Fish, World Book
- Mars
- Mollusks and similar sea creatures
- Freshwater life of the United States and Canada
- Trees of the United States and Canada
- The sun and other stars
- Ice storms
- The World Book encyclopedia, 2009, v. 11
- The World Book encyclopedia, 2009, v. 1
- Thunderstorms
- The World Book encyclopedia, 2009, v. 14
- Neptune and the distant dwarf planets
- Droughts
- Chinese of the Shang, Zhou, and Qin dynasties
- Amphibians & reptiles of the United States and Canada
- Insects of the United States and Canada
- The World Book encyclopedia, 2009, v. 18
- Earth and Earth's moon
- Tsunamis and seiches
- Wildfires
- The World Book encyclopedia, 2009, v. 5
- Earthquakes
- Astronomy
- Mercury and Venus
- The World Book encyclopedia, 2009, v. 22
- Reptiles
- Transportation
- The Polynesians
- The World Book encyclopedia, 2009, v. 21
- Australian aborigines
- The World Book encyclopedia, 2009, v. 10
- Blizzards
- The World Book encyclopedia, 2009, v. 4
- Africans of the Ghana, Mali, and Songhai empires