Terrarium Humidity
Measuring changes in air temperature, dew point and relative humidity in a plant terrarium.
PASPORT Humidity/Temp/
Dew Point Sensor (PS-2124A)
Lab Summary
In this experiment, we will use the Humidity/Temp/Dew Point Sensor to measure air temperature, dew point and relative humidity in a plant terrarium. We’ll then hypothesize reasons for any changes.
The amount of water vapor in the air is called humidity. As water molecules evaporate, the humidity of the air increases. Certain climate regions on earth (such as deserts, Arctic and Antarctic regions) have very low humidity, while other climate regions (such as tropical rain forests) have moderate to high humidity.
In general, the amount of water vapor that a given volume of air can hold increases as the temperature increases. A higher temperature allows more water to evaporate into water vapor. As the temperature goes down, the amount of water vapor in the air goes down because the water vapor molecules can condense into liquid form again. Therefore, the humidity drops. When the air holds all the water vapor it can at a given temperature, the air is saturated. The point at which saturation occurs is called the dew point.
Relative humidity is a common way to describe the amount of water vapor in the air. Relative humidity is a ratio that compares the mass of water vapor in the air to the mass of water vapor that the air can hold at its saturation point. Relative humidity is always written as a percentage.
For example, the average relative humidity in the rainforest is high, typically ranging from 75% to 95%.
Published: April 2002
Downloads
- Terrarium Humidity - PASPORT (43 KB, .zip)
Includes experiment setup, procedures and Datastudio file
- Terrarium Humidity - ScienceWorkshop (43 KB, .zip)
Includes experiment setup, procedures and Datastudio file
Here's What You Need
U.S. Educator prices shown.
Probeware (PASPORT System)
PASPORT Humidity/Temp/Dew Point Sensor (PS-2124A) - $81
Measures absolute humidity, relative humidity and air temperature. For use with PASPORT Interfaces.
Xplorer GLX (PS-2002) - $329
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
Probeware (ScienceWorkshop System)
Relative Humidity Sensor (CI-6559) - $119
Allows students to monitor single or continuous measurement of relative humidity.
Temperature Sensor (CI-6605A) - $39
Used for measuring the temperature of liquids, air, and other materials.
750 Interface, USB (CI-7650) - $659
The 750 Interface allows students to measure force, temperature, pressure, angular velocity, acceleration, current, & magnetic field with a built-in function generator and oscilloscope mode.
Other Materials
- Terrarium with plants
- Cover or lid for terrarium (i.e. plastic, aluminum foil…)
- Cup of hot water