A Bullfrogs view of...

Our Local Watershed and Water Education for Young Minds...

Brentwood Elementary VESD Mrs. Bishop's Class
  


   
   

 

 

 

Testing for Water Purity

 purity1

In the Field

Water testing should be done routinely, changes in water measurement are more important than the actual measured values

Temperature

To check for water quality at a local lake, river or pond. water temperature will be taken at the same time the tests are run.

Turbidity

Turbidity appears as cloudiness in the water, much like smoke in the air.

MATERIALS: circular piece of plywood 20 cm diameter, black paint, white paint, 15 m. rope, weight

CONSTRUCTION: Use the plywood, draw two intersecting lines on surface of disk tp divide it into four quarters. Paint two non adjacent quarters black and the two remaining quarters white. Drill a hole into the center. Attach a 15 m light rope by threading through the center hole. On the underside of the disk attach a weight to the rope. Mark the rope at one meter increments.

  1. Lower secchi disk into the water
  2. Record the depth that the disk reaches, as measured by the marks on the rope, before it disappears from sight.

pH Test

ph TEST measures acids or bases, the lower the number the more acidic the water. Optimum is 5.0 - 9.0, from a range of 0 to 14. Low pH can damage living organisms.

MATERIALS: water sample, pH paper, pH color chart

  1. Dip paper into water
  2. Match color to pH chart

Relative Stability

Relative Stability determines if there is a sufficient amount of dissolved oxygen in the water.

Materials: culture tube with cap, methylene blue indicator

  1. Drop three drops of methylene blue into culture tube
  2. Fill with water
  3. Replace cap. Water will be blue
  4. Check after 3 days
  5. Check again in 6 days. If water turns clear in three days or less it is oxygen deficient. If the water turns clear in six days or more there is plenty of dissolved oxygen.

Microscopic Organisms

Microscopic organisms test checks for plant or animal microorganisms and presence of salt.

MATERIALS: medicine dropper, microscope slides with cover slip, microscope

  1. Use dropper to place three drops of water on microscope slide
  2. Cover with slip
  3. Examine under 400X magnification on microscope
  4. Give visual accounting of plant or animal organisms
  5. Wait until slide dries out, check for salt crystals