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Increased Conductivity – Worksheet 3

 Brine Solution - Experimental Lake Group Names: _______________________________________________ Date: _______________________ Knowledge Base When the conductivity of a lake or river changes, it indicates there has been some sort of disturbance. The disturbance might result from natural or human activities, or it might be caused by physical, chemical, or biological factors.   Experimental Design How did you manage to create an experimental "lake" with at least 200 ml of water with a 1.5 mM initial salt concentration? (Explain your thinking process and calculations.)   Initial volume of your experimental "lake" _____________ Initial conductivity of the lake _____________ Data Collection Volume of the lake after the effluent was added _____________Conductivity of the lake after the effluent was added _____________   Data Management and Analysis By how many microsiemens did conductivity increase? _____________Use your standard curve graph or the regression equation to determine the salt concentration before and after the effluent was added.Concentration of salt in lake at the start ______________Concentration of salt in lake after effluent addition ______________Increase in mM of salt concentration ______________ How many milligrams of salt were added to your lake by the effluent _____________What was the percent increase in the salt concentration in your lake?   Interpretation of Results How accurate do you think your calculations are? Hypothesize what effect a similar amount of salt would have on plants and animals in a real lake.How might salt concentrations affect human use of the lake?     Reporting Results Ask each of the other small groups for their results and record how many milligrams of salt were added to each experimental lake. Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Rank the groups according to the amount of salt added to each lake.Least salt added_______________________________________ _______________________________________Most salt added