Apologia Science: Water Quality Tests

Update: Here are the instructions to make a Secchi disc and transparency tube to measure turbidity or water transparency.  If you are planning a stream study, make a transparency tube and bring an umbrella.


Last year, in Biology, my students performed several ecological activities.  Watershed studies, stream assay, and water quality tests make good science fair projects, too.  Lamont’s Water Quality Kits are the gold standard for water testing.  Students can perform several stream tests with an armored thermometer (or metal-backed thermometer), aquarium test kits, white ice cube trays, a fish net, a tennis ball, and a bucket.  5-in-1 or 6-in-1 test strips are easy to use and accurate.  The most useful tests are pH, nitrate/nitrite, and hardness.  Phosphates are difficult to measure.  Indicator solutions and pH strips are fine for testing acidity or alkalinity.  Kids like the aquarium test kits because they feel more scientific.  (Compare to the Lamont’s broad pH kit.). Fresh kits are better.  Try to use up the materials in six months or so.  The chemicals degrade.

Start with an overview of stream assay. (This intro has great reference citations, such as GLOBE.).  Students assess the stream’s temperature, pH, nitrates, hardness, dissolved oxygen, and macroinvertebrates. (Laminate guides and bring nets and white ice cube trays for sorting water critters.  The types of critters in a stream indicate the health of the stream.  The tennis ball is tossed in the water and used to time the stream flow.  Bring a tape measure to measure the distance tracked with the ball.). Now that you’ve opened Pandora’s box, take a look at National Geographic’s Field scope.  This is a free mapping project- a citizen science program.  GLOBE offers similar projects and programs.

Welcome to watersheds.  Here are several good guides. Try this on first.   Here are definitions of water quality indicators.  Crumpled Paper Watershed is an excellent way to explain what a watershed is.

The local forestry and soil and water conservation district should have more information.  Ask if they have an Enviroscape watershed model.  Check to see if the agency has a macroinvertebrate expert willing to teach.  The conservation district usually has an educator and the agency serves as a clearing house for other environmental agencies.  Don’t worry if you are new to watershed education.  Their job is to help.  I’ve worked with many agencies; some are better than others.  Keep asking until they put you in touch with someone helpful.

Watershed study Does not have to be expensive.  Go for it!