Ecology: Transpiration

The transpiration rate will be determined using a small piece of a plant. The plant will be attached to a PASPORT Barometer Sensor, and the change in pressure at the end of the plant stem will be recorded as the transpiration rate. In addition, the system will be challenged by increasing the humidity (using a plastic bag over the plant) to determine the effect of humidity on the rate of transpiration.

Motion Sensors

Students will observe that rate of transpiration is greater when the fan is operating and evaporation increases. Enlarge graph.

Lab Summary:

In this exploration, students will use a barometer as a potometer to measure the rate of water uptake in plants due to transpiration. This activity will demonstrate the concept of "transpiration pull." In addition, the investigation will explore the effects of environmental factors (air movement) on the rate of transpiration.

Download free labs:

(student versions)

Computer-based lab (PDF, 620 KB)

Xplorer GLX-based lab (PDF, 604 KB)

Method:

Use the Barometer as a potometer to measure the rate of water uptake in plants due to transpiration.

Here's What You Need:

Required for computer-based lab:

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

Probeware Required:

Other Materials Required:

Lab Manual:

The computer-based activity is included in Explorations in Biology (PS-2807). The Xplorer GLX-based lab is included in Biology with the Xplorer GLX (PS-2820). 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 Biology Lab Manual and Bundles
Xplorer GLX-based Biology Lab Manual and Bundles