Dissolved oxygen is one of the primary indicators of the quality of an aquatic environment. Oxygen enters water from the surrounding air, as a product of photosynthesis, and as a result of rapid movement of water. A Dissolved Oxygen Probe can be used in a wide variety of tests or investigations to determine dissolved oxygen concentrations (DO) and changes in dissolved oxygen concentrations.


In this Preliminary Activity, you will gain experience using a Dissolved Oxygen Probe as you determine the DO level of a water sample provided by your teacher.

After completing the Preliminary Activity, you will first use reference sources to find out more about dissolved oxygen issues in the environment before you choose and investigate a researchable question dealing with dissolved oxygen. Some topics to consider in your reference search are:

  • water pollution
  • eutrophication
  • thermal pollution
  • photosynthesis
  • cellular respiration