Relative Humidity
Recommended for grades 6–12.
Introduction
If you live in a place where it gets hot and muggy, you know about humidity. Humidity is a measure of the amount of water vapor in the air. When meteorologists report humidity, however, they are usually referring to the relative humidity. Relative humidity is the amount of water vapor in the air compared to the maximum amount it can hold. The maximum amount of water vapor air can hold varies depending on its temperature – warm air can hold more water than cold air.
One way to measure relative humidity is by observing how easily water evaporates. The drier the air, the faster water will evaporate. Have you ever noticed that you feel cooler when you have just stepped out of the water? This is because as water evaporates, it cools the surface it evaporated from. If we measure how much a Temperature Probe cools as water evaporates off of it, we can calculate the rate of evaporation and therefore the relative humidity.
In this experiment, you will use two Temperature Probes to determine relative humidity at several different locations.
Objectives
In this experiment, you will
- Measure temperature.
- Determine relative humidity.
- Explain your results.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
Additional Requirements
You may also need an interface and software for data collection. What do I need for data collection?
Download Experiment Preview
The student-version preview includes:
- Step-by-step instructions for computer-based data collection
- List of materials and equipment
Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.
Standards Correlations
See all standards correlations for Earth Science with Vernier »
Included in the Lab Book
Vernier lab books include a CD with word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.