Costa Rica Rainforest Experiment
"Volcano Vertigo"

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

PASPORT Barometer Sensor
(PS-2113)


Purpose

To observe changes in atmospheric pressure as elevation changes.

Overview

In this activity, students will use a barometer sensor to measure the change in atmospheric temperature during a drive to the summit of Poas Volcano and back down.

Background Information

Poas Volcano (2,708 meters or 8,884 feet) is located in the Central Volcanic Mountain Range, 37 kilometers north of Alajuela on the Alajuela-San Pedro de Poas route.  It is one of the most spectacular volcanoes in Costa Rica and has the largest geyser in the world.  This park protects various types of forest containing abundant epiphytes and parasitic plants that grow on tree trunks.

Poas’ crater is an enormous hole, stretching 1 kilometer in diameter and 314 meters in depth.  The long-dormant von Frantzius composite cone, the oldest eruptive center of the massif, is at the north of the arctic crater.  Another cone, named Botos, is to the southwest.  It was the active center of the volcano until 7,500 years ago and now contains clear, cold water (Botos Lake).  The lake is approximately 400 meters in diameter.

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Equipment

Data Collection Procedure

GLX Setup:

1. Plug the PASPORT Barometer Sensor into the port on the top of the Xplorer GLX.

2. From Home screen, press I to access the Sensors screen.

3. Press c to change the sample rate unit to minutes. Change the sample rate to 5. The Barometer Sensor is now configured to take data every 5 minutes.

Volcano GLX Screen

4. When you depart from Selva Verde, press s to begin recording data.

5. If your ears pop on your way up the mountain, observe your GLX carefully on the way down and make a note of the time at which they popped.

6. Continue recording data until you return to Selva Verde. Press s to stop recording data.

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Data Analysis

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

2. Examine the data and determine if there is a relationship between barometric pressure and elevation.

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Conclusions and Extensions

1. What relationship did you observe between barometric pressure and elevation? How can you explain the data you observed?

2. Consider how the day’s weather patterns may have influenced the barometric pressure data you recorded.  Can you draw any conclusions about current weather conditions and the associated pressure data?

3. What common physiological responses do people sometimes experience as a consequences of changing barometric pressure.  Compare your experiences with others in the group.

4. If your ears popped during the trip, at which point were they most pronounced? Can you explain why?

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