| ChemicalElements.com: Oxygen [ Mature Teens ] - Features basic information, an atomic structure diagram, facts about oxygen and a table of isotopes. http://www.chemicalelements.com/elements/o.html |
| LANL: Oxygen [ Teens/Mature Teens ] - Details of the history, sources, forms, compounds, and isotopes of oxygen. http://periodic.lanl.gov/elements/8.html |
| Visual Elements: Oxygen [ Mature Teens ] - Explains the uses and physical properties of oxygen. Includes a visual representation and downloadable animation. http://www.chemsoc.org/viselements/pages/oxygen.html |
| WebElements: Oxygen [ Mature Teens ] - History, uses, occurrence, compounds, and properties. Features a picture of liquid oxygen and a sound file. http://www.webelements.com/webelements/elements/text/O/key.html |
| Wikipedia: Oxygen [ Mature Teens ] - Article covering properties of the element, including its history, applications, and characteristics as well as safety precautions. http://en.wikipedia.org/wiki/Oxygen |