PASCO PS-2108 Dissolved Oxygen Sensor - Manual (Page 27)

Model No. PS-2108 Dissolved Oxygen Sensor
23 ®
Experiment 5: The Effect Of Respiration On Dissolved
O
2
Concentration
Purpose
The purpose of the experiment is to explore the effect of respiration on dissolved O
2
concentrations.
Materials required
• Dissolved Oxygen Sensor (PS-2108)
• 400 ml deionized water
• PASPort interface hardware and DataStudio software
• aquarium pump or large bottle
• 1 package rapid active yeast
• 600 ml beaker (2)
• table sugar
Optional materials
• hot plate/stir plate and magnetic stir bar
Procedure
1. Follow the directions on the yeast package to activate the
yeast in a beaker using tap water and sugar.
2. Set up and calibrate the Dissolved Oxygen Sensor.
3. Stir 1 teaspoon sugar into the deionized water and
saturate it with air.
4. Monitor the dissolved O
2
concentrations of the
deionized sugar water while stirring gently with the
dissolved O
2
probe.
5. When the reading stabilizes, click the Start button in
DataStudio and record data for 30 seconds.
6. After 30 seconds, transfer about 1 teaspoon of the activated yeast solution into the water.
7. Continue stirring with the probe and recording data for about 10 minutes or until the
oxygen level stabilizes.
Figure 1
Transfer activated yeast solution to the
test beaker.