Costa Rica Rainforest Experiment
"Go With The Flow"

- Equipment
- Data Collection Procedure
- Data Analysis
- Data Table
- Conclusions and Extensions

PASPORT Temperature Sensor
(PS-2125)

Purpose

To observe the changes in temperature in a large body of water.

Overview

In this activity, students will use a temperature sensor to measure changes in temperature in the Sarapiqui River. Students will investigate how temperature varies across a large body at different depths, positions, and widths.

Background Information

Not all molecules in a liquid have a constant temperature.  Temperature is a measure of the average kinetic energy of the molecules in a substance.  Water that collects in a pond, for example, will be colder at the bottom and warmer at the top.  The flow of water will also affect temperature, since water may be redistributed from one area of a stream or river to another, causing a rise or drop in the average temperature of the surrounding water.

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Equipment

Data Collection Procedure

GLX setup:

1. Connect the PASPORT Temperature Sensor to the port on the top of the GLX. Connect the stainless steel probe to the sensor.

2. Press I to access the Sensors menu. Press F to change the mode to Manual.

Equipment setup:

1. Use the rubber bands to fasten the temperature probe to one end of the stick or pole.

2. Mark the stick or pole at equal intervals.

Record Data:

Depth

1. Lower the pole into the river. Mark the depth.

2. Press s. The GLX is now ready to begin taking data. Wait approximately 30 seconds for the temperature of the probe to equalize.

3. When the reading stabilizes, press f to take the data point. When the Keyboard Data prompt appears, use the keyboard to type in the depth.

4. Repeat for several different depths at the same location.

5. Press s to stop recording data.

Position

1. Repeat the steps above keeping the probe at a constant depth but changing the location relative to the shore.

Width

1. Repeat the steps above keeping the probe at a constant depth but taking points at a narrow then wider section of the river.

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Data Analysis

1. From the Home screen, press F to access the Graph display.

2. Examine each run of data.  You can change which run is displayed on the graph by pressing c to highlight the active fields and using the arrows to highlight run number.  Press c to change the run.

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Data Table

    Trial #
    Description

    Results
    (Temperature)
    1.
    Depth #1
     
    2.
    Depth #2
     
    3.
    Depth #3
     
    4.
    Location #1
     
    5.
    Location #2
     
    6.
    Location #3
     
    7.
    Narrow section
     
    8.
    Wider section
     

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Conclusions and Extensions

1. Explain the relationship of temperature in flowing water to water depth.

2. Was there any correlation between water temperature and position relative to the river’s shore?

3. When water was sampled from wider parts of the river compared to narrower parts of the river, what temperature trends were observed?

4. How would your results vary in a slower or faster moving river?

5. What effects might temperature variation have on aquatic organisms that frequent this river?

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Back to Costa Rica Summary -- October 2002