Carbon Transfer Through Snails and Elodea – Virtual Lab



CP Biology Name_____________________________

Carbon Transfer Through Snails and Elodea – Virtual Lab

1. First, watch this video on color changes in BTB: . In this video, they are heating a white substance to create CO2 gas which is then bubbled into the bromothymol blue solution so that you can see how it can act as a carbon dioxide detector because it detects the drop in pH (because carbonic acid is produced when the CO2 combines with the H2O. In the original lab packet it directs you to blow into the solution with a straw. Either way, you would see carbon dioxide bubbling into the bromothymol blue solution, with the results being the same.

2. Directions to Virtual Lab

From the Internet: Go to

Under Labs, select virtual labs. Select Carbon Transfer Through Snails and Elodea from the list of labs.

Listen to (read) the introduction/summary. Then close (X) that dialog box.

Explore each item in the lab. You must click on each item in the checklist.

Then click “Procedure” in the upper left.

Click on the “Lab Notebook” in the upper right hand corner and write your hypothesis there. Also write it below:

______________________________________________________________________

______________________________________________________________________

______________________________________________________________________

In Step 2 enter the following in the “Lab Notebook” as well as below

I will measure the level of CO2 by: ________________________________________

My independent variable will be: __________________________________________

My control group will be: ________________________________________________

Then enter “8 for the number of test tubes.

Tube 1 (light): 0 snails, 0 elodea Tube 5 (dark): 0 snails, 0 elodea

Tube 2 (light): 1 snail, 0 elodea Tube 6 (dark): 1 snail, 0 elodea

Tube 3 (light): 0 snails, 1 elodea Tube 7 (dark): 0 snails, 1 elodea

Tube 4 (light): 1 snail, 1 elodea Tube 8 (dark): 1 snail, 1 elodea

Arrow forward to Step 3 to put 8 tubes in the test tube rack and add BTB solution to each.

Arrow forward to Step 4 to add organisms to the tubes as above.

Open the digital “Lab Notebook” to make your color predictions. Write them in the chart below. At the bottom, click “Add Stoppers” to add stoppers to seal up your test tubes. Place the test tube rack under the grow light and under the test tube rack cover. Press start to leave the tubes for 24 hours.

Arrow forward to Step 6. Observe the change in color. Open the digital Lab Notebook to record the final “End Color” for each tube. Write the results in the chart below.

Arrow forward to Step 7. The computer will state you are ready to draw your conclusions. You may now close the program.

Data/Results:

|Test Tube |Contents |Starting Color |Predicted End Color |End Color |

| | | | | |

|1 – Light | | | | |

| | | | | |

|1 – Dark | | | | |

| | | | | |

|2 – Light | | | | |

| | | | | |

|2 – Dark | | | | |

| | | | | |

|3 - Light | | | | |

| | | | | |

|3 - Dark | | | | |

| | | | | |

|4 - Light | | | | |

| | | | | |

|4 - Dark | | | | |

Conclusion:

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