Lesson Plan

How Clear Is the Water?

front end of a kayak in a blue lake, looking out toward cloud-covered mountains

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Grade Level:
Seventh Grade-Twelfth Grade
Biology: Animals, Biology: Plants, Chemistry, Climate Change, Ecological Engineering, Ecology, Environment, Physical Science
6-8 Class periods (50 minutes each)
Group Size:
Up to 36 (6-12 breakout groups)
National/State Standards:
HS-LS2 Ecosystems: Interactions, Energy, and Dynamics
HS-ESS2 Earths Systems
HS-ETS1 Engineering Design
ecosystem, turbidity, water quality, secchi disk


In this lesson students will test their knowledge of ecosystems and the qualities necessary to sustain life by creating Secchi disks, testing turbidity (water clarity), and making predictions about the habitat that might exist. This fun, hands-on lesson allows students to be the scientist and make predictions based on their findings in their lab reports.


  • Students will be able to explain the impact of water clarity on ecosystems functionality.
  • Students will create a product to analyze a solution.
  • Students will complete a lab report.


Many marine or aquatic ecosystems depend on the quality or productivity of water. Water heavy with glacial sediment is often not highly productive because of the silt concentration and temperature, where salt water tends to be warmer and teeming with life. Students will be working in a local lake or ocean (or classroom if you don’t have a nearby body of water) to test its turbidity and analyze the life that resides in the body of water.

The final result should be a lab report and an engineered product that students have taken time to create and explain. This lesson fits well with an engineering project or into an ecology lesson. The goals are to engage students in the water near them,with the life around them and to have them think of creative solutions to sustain their environment.


The materials with the PDF lesson are all inclusive. It is a presentation to start students off and spearhead the lesson. There is an activity manual with all the portions suggested in the procedure as a template for teachers to use and hand out.



Students will create a lab report (to your specifications or the ones outlined in the lesson) for grading. Students will have a creatively engineered Secchi disk with explanation as to how it will work better and what its primary goal for data would be.

Park Connections

Lake Clark National Park and Preserve uses their Southwest Alaska Network (SWAN) team to measure, among other things, turbidity, dissolved oxygen content, pH, and temperature. They have been gathering data to analyze, as the climate is changing, glaciers are melting, and populations of salmon are fluctuating. The park is keeping a close eye on the water in Lake Clark and it’s surrounding lakes in an attempt to understand the importance of changes.


Teachers with an interested group of students can encourage their students to field test their created Secchi disks, perfect their disks, and retest them. Students can also create a report on a career as a scientist working on water quality monitoring, as a hydrological technician, or other related field.

Additional Resources

Students who are interested should check out the SWAN website. That can give them more information about the SWAN team, the projects that are ongoing, and a broader information base.


Secchi disk, water clarity (turbidity), ecosystem, productivity

Last updated: July 11, 2018