How Clear Is the Water?
OverviewIn 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.
BackgroundMany 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.
MaterialsThe 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.
This is the power point that will start your lesson. It offers opportunities for students to discuss both among themselves and with the teacher their thoughts and insight. Download
The activity manual is a complete student handbook of materials to use while working through the idea of water quality. It includes a Turbidity Lab, Engineering process outline, Lab Write-up outline, and teacher notes and suggestions. This is the main portion of the activity. Download
Part 3: Once you have finished the lab, you can take it a step further and work through the engineering assessment. Students should be given a range of materials or bring their own materials in to create a Secchi disk.
The goal behind the engineering portion is for students to realize a problem related to the turbidity of water, brainstorm a creative solution, and test a product they have created. There is a template to take students through the engineering process in the activity manual. With this activity, you can suggest students look at the ecology of an area, the plants and animals who live within a body of water, a better Secchi disk design that makes it easier to record, or a Secchi disk that tests for something other than turbidity (dissolved oxygen, pH, etc.). The idea is that students are using their brains to create something new. (2-3 50 min periods)
Part 4: The final assessment should be a complete lab write up. In the activity manual there is an outline of a lab write up, but you can modify it depending on your requirements. The lab write up should be a comprehensive review of the engineering portion (what they created), with a solid foundation from the Turbidity Lab. Students can complete this activity as a group or as individuals. (1-2 50 min periods)