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

1. 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.)

    

2. Initial volume of your experimental "lake" _____________
   Initial conductivity of the lake _____________

Data Collection

3. Volume of the lake after the effluent was added _____________
   Conductivity of the lake after the effluent was added _____________

Data Management and Analysis

4. By how many microsiemens did conductivity increase? _____________
   
   
5. 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 ______________
   
   
6. How many milligrams of salt were added to your lake by the effluent _____________
   
   
7. What was the percent increase in the salt concentration in your lake?

Interpretation of Results

8. How accurate do you think your calculations are?
   
   
   
9. Hypothesize what effect a similar amount of salt would have on plants and animals in a real lake.
   
   
   
10. How might salt concentrations affect human use of the lake?

Reporting Results

11. 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
    
    
12. Rank the groups according to the amount of salt added to each lake.
    
    Least salt added
    
    _____________
    
    _____________
    
    _____________
    
    _____________
    
    _____________
    
    _____________
    
    Most salt added