012-08402A
Carbon Dioxide Sensor
3
®
Collecting Carbon Dioxide Samples
Use the supplied sampling bottle to collect air or other
samples, such as an atmospheric sample or the CO
2
gas produced from germinating seeds. Small amounts
of solid samples, such as plants or other organisms,
can be placed in the bottom of the bottle.
CAUTION:
Do not try to remove the probe
from the sensor. The probe is not removable.
To collect an atmospheric sample:
When collecting
air, keep the bottle upright and the neck open (without
the stopper). Wait long enough to allow atmospheric
air to fill the bottle. Insert
the probe with stopper
into the top neck of the
bottle. Ensure the stopper
fits snugly into the neck
of the bottle before taking
a reading.
To collect expired air or
other gas samples:
Collect the sample in a
plastic bag and clamp the
bag. To take a reading,
unclamp the bag and
immediately place the
plastic bag over the probe and stopper. In some cases,
a valve, tubing with stopcock, or chamber may be
necessary to prevent atmospheric gas from entering
the bag and mixing with the collected sample.
9.
To verify the calibration, observe the sensor’s
reading in DataStudio. The reading should be stable
at approximately 400 ppm (±50 ppm).
Note:
If the sensor’s reading drifts or seems too high
or low, recalibrate.
Figure 2: Sensor
placement in bottle
Suggested Experiment: Cellular Respiration
of Peas
Equipment required:
1/4 cup of pea seeds, piece of
dark cloth, CI-6561 CO
2
Gas Sensor with bottle and
stopper,
ScienceWorkshop
interface, DataStudio,
Temperature Sensor (optional)
1.
Connect the Carbon Dioxide Gas Sensor to a
ScienceWorkshop
interface.
2.
Put the dry pea seeds into the bottle supplied with
the sensor. Insert the probe with stopper and
sensor into the bottle.
3.
In your data collection software, click the
Start
button to take a reading of the concentration of
carbon dioxide gas in the bottle. Record data for
about 10 minutes; this is the baseline reading
before germination.
4.
Disconnect the sensor from the sensor/bottle
assembly.
5.
Moisten the peas with a few teaspoons of water.
Place a dark cloth over the bottle, and allow the
peas to germinate in the bottle overnight.
6.
Following germination, reconnect the sensor to the
interface and click the
Start
button. Monitor the
CO
2
gas reading for about 10 minutes.
CAUTION:
Do not allow the probe or sensor
assembly to get wet at any time!
7.
Compare the rate of carbon dioxide generation
before and after germination. Explain your results.
What is causing the change in carbon dioxide
concentration?
8.
(Optional): Repeat step 6 with the bottle placed in
water baths of different temperatures.
Note:
If you have a Temperature Sensor or
thermometer available, you can monitor both the CO
2
and temperature every 5 minutes for 20 minutes.
