How Do You Measure Dissolved Oxygen In Water?
When scientists learned how measure dissolved oxygen in water, they discovered that bodies of water breathe—at least the ones with plant life in them do. The dissolved oxygen level in a healthy pond or lake rises and falls rhythmically with the rising and setting of the sun. This occurs because the plants in the water are producing oxygen via photosynthesis when the sun is up, and they stop producing the oxygen when it sets. You can measure the dissolved oxygen in a body of water yourself. Cheap, self-explanatory test kits and meters are available for you to purchase, or you can use the Azide-Winkler titration method if you have the appropriate materials available. Fill your 300-mL BOD bottle with the water you are testing. It is very important that you do not introduce bubbles to the bottle as you fill it, because this will add oxygen to the water. The best way to fill it is to half-submerge the opening of the bottle and let the water slowly flow in. As the bottle fills, submerge th
