Hydrosphere: The Air-Water Interface

Determine the relationship between dissolved oxygen and water temperature, and between humidity and air temperature.

Lab Summary:

The interaction between water and the atmosphere is critical to plant and animal survival. Dissolved oxygen, which enters the water through aquatic plant photosynthesis and contact with the atmosphere above the water, provides the materials necessary for aquatic organisms' respiration. Energy from the sun's rays increases water temperature, causing water to evaporate and enter the air. This increase in temperature also affects water's ability to contain dissolved oxygen for the same reason. The atmosphere's ability to contain water is highly dependent on temperature and is critical to the function of the water cycle.

In this lab, students will measure temperature, humidity, and dissolved oxygen to observe the interactions between water and air, and determine how temperature changes affect humidity and dissolved oxygen in a "closed" system. Students should recognize that they are observing a system in dynamic equilibrium, and identify parts of each.

Download free labs:

(student versions)

Computer-based lab (PDF, 518 KB)

Xplorer GLX-based lab (PDF, 36 KB)

Method:

Use a Temperature, Humidity/Temperature/Dew Point, and Dissolved Oxygen Sensors to observe the interactions between water and air, and determine how temperature changes affect humidity and dissolved oxygen in a "closed" system.

Here's What You Need:

Required for computer-based lab:

(See lab download for Xplorer GLX-based lab requirements, which may differ)

Probeware

• PASPORT Temperature Sensor (PS-2125)
• PASPORT Humidity/Temp/Dew Point Sensor (PS-2124)
• PASPORT Dissolved Oxygen Sensor (PS-2108)
• Xplorer GLX Graphing Datalogger (PS-2002)
  (or alternate PASPORT interface -- see other options)

Other Materials

• Small Base & Support Rod (SE-9451)
• Clamp, Buret (2) (SE-9446)
• Clamp, Three-Finger (SE-9445)
• Hot Plate
• Stirring Rod
• Beaker, 1-L
• Protective Gear
• Water, Cold, 500.0 mL
• Water, Warm, 500.0 mL
• Plastic Bag

Lab Manual:

The computer-based activity is included in Explorations in Earth and Environmental Science (PS-2809). The Xplorer GLX-based lab is included in Earth and Environmental Science with the Xplorer GLX (PS-2821A). Both manuals are complete with Teacher Information pages, student instructions and handouts, and sample data.

For your convenience, we offer bundles which provide the probeware for the activities in the manual. For more, please see:
Computer-based Earth and Environmental Science Lab Manual and Bundles
Xplorer GLX-based Earth and Environmental Science Lab Manual and Bundles