Carbon Transfer through Snails and Elodea-Virtual Lab
Hypothesis:
Explain how carbon dioxide (CO2) cycles in aquarium water through snails and Elodea.
Name:
LAB NOTEBOOK
If____________________________________________________________________
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then__________________________________________________________________
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because_______________________________________________________________
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Experimental Design:
Period:
Dependent variable
The level of CO2 in your test tubes is the dependent variable
Operational definition
Determine the operational definition of your dependent variable.
How will you measure the dependent variable?
In my experiment I will measure the level of CO2 by:
Date:
Independent variable
Identify your independent variable.
Decide which condition you will test:
-the number of snails in a test tube (1 or 2)
-the number of Elodea plants in a test tube (1 or 2)
-the amount of light (light or no light)
NOTE: Each of your test tubes will be filled with BTB (Bromthymol Blue) solution.
In my experiment, my independent variable will be:
Control
Determine your control. A control is a set-up against which the change in the dependent
variable can be measure. Describe what is in the test tube used for your control condition.
The set-up for my control condition is:
Experimental Design:
You have a total of 8 tubes available for your experiment.
Each of your test tubes will be filled with BTB (Bromthymol Blue) solution.
I will use _______ test tubes.
-At least one of the test tubes will be used for your control condition.
-The other test tubes will be used for your experimental conditions.
Determine the set-up for each tube:
Tube 1: BTB solution, __________________________________________________
Tube 2: BTB solution, __________________________________________________
Tube 3: BTB solution, __________________________________________________
Tube 4: BTB solution, __________________________________________________
Tube 5: BTB solution, __________________________________________________
Tube 6: BTB solution, __________________________________________________
Tube 7: BTB solution, __________________________________________________
Tube 8: BTB solution, __________________________________________________
Data
Test Test tubes in
tube Light or Dark
1
2
3
4
5
6
7
8
Contents
Starting
color
Predicted
end color
End color
Analysis / Conclusion:
ANSWER ALL QUESTIONS USING COMPLETE SENTENCES OR LOSE POINTS!
1. Analyze: What was the purpose of the bromthymol blue?
Why did the color of the bromthymol blue change?
2. Analyze: What was the importance of a control in your experiment?
What would you conclude if the color of the solution in the control changed?
3. Infer: When you began the experiment, was there CO2 in the water? How do you know?
In the test tubes that contained Elodea, where did the CO2 go?
4. Infer: Which gas did the snails release? What observation supports this inference?
5. Analyze: What was your hypothesis? Was your hypothesis proved/disproved?
Explain how you know.
6. Analyze: How is the relationship between snails and Elodea a biological system?
7. Apply: Based on the results of your experiment, explain why you need to add the
Elodea to your snail aquarium.