Name:
Online Lab: Carbon Transfer Through Snails and Elodea
Record answers in blue, bold font
Go to
http://www.classzone.com/cz/books/bio_07/resources/htmls/virtual_labs/virtualLa
bs.html
(If the link does not work,
go to http://www.classzone.com/cz/index.htm
Enter Science, High School; NC; Go
Click Biology 2008 (book on left)
Click Virtual Labs (left side 2nd row)...continue with directions below)
Click on Carbon Transfer Through Snails and Elodea. Read through the
directions and complete this lab, answering the lab notebook questions (in bold)
in the appropriate locations below. When indicated, enter the lab set-up as
indicated below to assist you.
(NOTE: You will make entries about your observations and predictions in
the online lab notebook in order to advance through the online experiment.
However, you can type anything in the required location to advance; it does not
have to be the correct answer or what you have recorded in this lab worksheet.)
Hypothesis – Step 1
1. How does carbon dioxide cycle in aquarium water through snails and
Elodea?
Experiment – Step 2
2. Measuring CO2: How will you measure the level of CO2? (Hint: look at
the bottom right corner of the lab bench graphic!)
3. Independent variable: Type “The number of Elodea plants in a test tube”.
This is what will vary from one test tube to the next.
4. Control: Your control should be a test tube without any Elodea in it, so
that you can determine what effect the Elodea has on the levels of carbon
dioxide in the test tube. Type “a test tube with one snail, but without any
Elodea”
5. Experimental Design: The more trials the better! How many test tubes
will you use? ___
a. Identify the set-up for each tube, using Tube #1 as your control:
Tube #1: __________________________ (See #4 above for
help)
Tubes #2-7: 1 snail + 1 Elodea
Data
Step 4 - Complete the data table below – contents and predicted end color
Step 6 - Complete the data table below – end color (actual)
Test Tubes
1
2
3
4
Test Tubes
1
2
3
4
Contents
Starting Color
Contents
green
green
green
green
Starting Color
Predicted End
Color
End Color
(Actual)
Predicted End
Color
End Color
(Actual)
green
green
green
green
Analyze and Conclude (Step 7) (Note, the numbers of questions here and in
the lab notebook differ.)
1. What is the relationship between snails and Elodea?
2. Why did the color of the bromthymol blue change?
3. What was the importance of a control in your experiment?
4. What would you conclude if the color of the solution in the control
changed?
5. When you began the experiment, was there CO2 in the water?
6. In the test tubes that contained the Elodea, where did the CO 2 go?
7. Which gas did the snails release?
8. What observation supports your answer to the question above?
9. Based on the results of your experiment, explain why you need to add the
Elodea to your snail aquarium.