LabLearner—The Science of Learning
LabLearner—The Science of Learning

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Watersheds

Deep Analysis

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Deep Analysis

Watersheds

Deep Analysis

Use the questions below to go deeper into the scientific concepts and applications of each Investigation. Note that questions highlighted in orange text are also featured in Phase 3.1 (Conclusions) of the Student Guide PDF.

Investigation 1

      1. What would happen in a stream channel if water velocity increased suddenly? Discharge would also increase suddenly. The stream might overflow its banks and cause flooding, and more water erosion might also occur.

       2. Explain how water pollution in one area of a watershed may be distributed to other areas. If a pollutant accidentally enters a body of moving water, like a stream or river, one would expect the pollutant to be transported downstream. The river and its tributaries upstream from the site of pollution would be much less or not affected by the pollutant. 

      Investigation 2

          1. How was a watershed modeled in this Investigation? A watershed was modeled using a beaker filled with water to represent a stream or river. Water movement was simulated by stirring with a stir bar. Sediment in the water was modeled with flour.

          2. What is sediment? Sediment is made of particles of rock, soil, and other materials that are found in the water of a watershed. What is sedimentation? Sedimentation is the process by which sediment settles out of the water to the bottom of a watershed.

          3. How does the amount of sediment in the water relate to water velocity? As water velocity increases, more sediment is churned up from the bottom and is suspended in the water. Less sedimentation occurs at high water velocities.

          4. What is turbidity? Turbidity is the cloudiness of the water. 

          5. How does the amount of sediment in the water relate to turbidity? The more sediment that is suspended in the water, the cloudier the water will be and the higher the turbidity will be.

          6. What is a spectrophotometer? A spectrophotometer is an instrument that measures the amount of light that passes through or is absorbed by a liquid.

          7. Why did you use a spectrophotometer in this Investigation? In this Investigation, a spectrophotometer was used to determine the turbidity of the water at different velocities. Turbidity was determined by measuring % Transmittance – the amount of light that passes through the water. Water with high turbidity has a lower percent transmittance.

          Investigation 3

            1. What is dissolved oxygen? Dissolved oxygen is oxygen gas in water.

            2. Why is dissolved oxygen important in watersheds? Organisms that live in water depend on dissolved oxygen to survive. The amount of dissolved oxygen in water determines what kind of organisms can live in the water.

            3. What instrument did you use to measure dissolved oxygen content? Students used an oxygen meter to measure dissolved oxygen.

            4. What factors can affect the dissolved oxygen content of a watershed? During the course of this Investigation, students discovered that dissolved oxygen content can be affected by temperature, salinity, and water velocity.