This site offers a good amount of information on characteristics of the earth and its make up as well as characteristics of the oceans. It provides an explanation and visual aids for the water cycle (a.k.a. the hydrologic cycle) as well as readers theater scripts to go along. There are tabs for further information on continent drift, clouds, the atmosphere, the magnetosphere and more. Students can find links to diagrams to label for practice, quizzes and other activities. This website is ideal for 3rd and 4th graders, but also can be useful resource for teachers looking for practice for students.
The Oceans, The Earth and The Water Cycle!