Today students are going to compare the data they collected over the past two days with a peer-reviewed study. They are going to determine where the data they collected is similar and where it is different from the peer-reviewed study. This is the final day of a three day lab. Find day one here and day two at this link. Here is an overview of what students will learn today.
Explain to students that they will be looking at an explanation summary and data overview of the peer-reviewed study, "Phytoremediation of Partially Treated Wastewater by Chlorella vulgaris."
Using the same lab groups that were assigned for day one and two of this lab, students should read through the student handout and answer the questions throughout the handout.
Using the provided handout, students will compare the data they collected with the a 2012 study, "Phytoremediation of Partially Treated Wastewater by Chlorella vulgaris." This study looked at the ability of a pure strain of algae to remove pollutants from waste water.
First have student read the abstract of the paper and highlight the following:
Next have students take a closer look at the organism, equipment, and tests performed in this experiment in the Materials and Methods section and:
Have students look at the results and explanation of the results.
(Note: Here are some samples of some typical student work (Total Nitrogen Graph, COD graph, and Total Phosphorus graph). Here are several examples of excellent student work (Total Phosphorus graph, COD graph, Total Nitrogen graph). All criteria were met in this graphic analysis. A line of best fit was determined. Descriptive statistics were calculated. A summary of the graph's trends were included. In the examples of typical student work only line of best fit was determined. This student was familiar with line of best fit because we have determined it in a previous class. The other two tasks were unfamiliar and so they chose not to attempt them. The next day I remind this student how what tools to use to finish the tasks.)
Next, have students look at the VSS graph and write a trend that explains what happened to the VSS over the course of the 14 day study
Finally, students should write a conclusion of the study based on what they have read.
Have students compare the shape of Removal of Pollutants with Time graph from the 2012 Chlorella study to the graph they made from the data they collected from yesterday. Ask them to list the similarities and differences.
Remind them in the Chlorella study that the algae removed the maximum amount of pollutants that it could (hence the shape of the graph). If the graph that the students made does not mirror the Chlorella study graph, then the algal mat could remove more of the copper from the simulated wastewater.
Have students extrapolate their graph and make a prediction concerning how long they think it would take the algal mat to reach the maximum amount of removal of pollutants. Have them record their prediction in their lab notebook and explain their thinking.
Finally, explain to students that by making these types of models, scientists can determine the amount of time wastewater can remain in a holding tank before it should be moved to maximize the removal of pollutants.