Name
Date ________Class
Lab A
45 minutes
Can you observe part of the carbon cycle?
The carbon cycle includes all of the paths that carbon takes as it is transferred through
the environment. During one part of the carbon cycle, tiny ocean organisms called
phytoplankton (fi toh PLANK tuhn) take in carbon dioxide gas from the air. The carbon
dioxide gas is converted to calcium carbonate, which the phytoplankton use to build their
skeletons. When phytoplankton die, many of them sink to the bottom of the ocean, where
their skeletons become fossilized. Over time, these fossilized skeletons build up and turn
into chalk. When this chalk is weathered by rain and waves, it releases carbon dioxide gas
into the air. This gas can then move through the many paths of the carbon cycle.
Question
How can you model part of the carbon cycle?
Materials
bromthymol blue
powdered calcium carbonate or crushed natural chalk
vinegar
250-mL Erlenmeyer flask
20-mL test tube
Balloon
filter paper
Safety
Procedure
1. Read and complete a lab safety form.
2. Measure 10 g of calcium carbonate powder onto filter paper.
3. Pour the calcium carbonate powder into a 250-mL Erlenmeyer flask.
4. Add 50 mL of vinegar to the flask.
5. Quickly stretch the mouth of the balloon over the opening of the flask. Record your
observations.
Lab A continued
6. Fill the test tube almost to the top with water.
Add 15 drops of bromthymol blue, a chemical indicator that turns yellow when it
is exposed to carbon dioxide. Observe the color of the liquid in the test tube.
7. Pinch the neck of your balloon and remove it from the flask.
Place the neck of the balloon over the mouth of the test tube and then release
the neck, allowing the gas to enter the test tube. Record your observations.
Lab Tips
Carefully swirl the calcium carbonate and vinegar in your flask to get the most gas from
your reaction.
Analyze and Conclude
8. Interpret Data What happened to the color of the liquid in the test tube? What did
this indicate?
9. Identify Where did the gas in the balloon come from?
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Interactions of Living Things
Name
..Date
Lab A continued
10.
The Big Idea Describe the part of the carbon
cycle you modeled in this experiment. How do living
things affect this part of the carbon cycle? How do
nonliving things affect this part of the carbon cycle?
Communicate Your Results
Draw the carbon cycle. Highlight the parts of the carbon cycle you modeled in this
experiment.
..Class