TITLE:Dew Point vs. Relative Humidity
5-8
CONNECTIONS TO THE CURRICULUM: Math/Science
OVERVIEW:
Relative humidity and dew point (or dewpoint temperature) are two parameters which describe the amount of water vapor in the atmosphere. However, dew point is a substantially better indicator of the actual water content of the air. Relative humidity is dependent not only on the amount of moisture in the air, but also on the air temperature. Dew point, on the other hand, is only dependent on the amount of moisture in the air.
STANDARDS:
Core Content
MA-05-1.1.3
Students will compare (<, >, =) and order whole numbers), fractions and decimals, and explain the relationships (equivalence, order) between and among them.
MA-05-1.2.1
Students will apply and describe appropriate strategies for estimating quantities of objects and computational results in real-world problems.
Program of Studies
MA-05-2.2.2
Students will describe, define, give examples of and use to solve real-world and mathematical problems nonstandard and standard (U.S. Customary, metric) units of measurement.
MA-05-2.1.3
Students will use measurements to identify, describe, sort and compare attributes of objects and apply these to solve real-world and mathematical problems.
GEOGRAPHIC SKILLS:
Acquiring Geographic Information
Organizing Geographic Information
Answering Geographic Questions
Analyzing Geographic Information
TIME:60 minutes
MATERIALS REQUIRED:
Computer
Downloaded Mesonet Data
Excel Software (optional)
Graph Paper
Pencil
OBJECTIVES:
Given a 24-hour graph of air temperature, relative humidity, and dew point, the student will be able to describe, for each plot, at least one reason why the variables change (or don't change) during the day.
Given scenarios which include illustrations of the dependence of relative humidity on temperature, the student will be able to identify and describe the problems with using relative humidity as the indicator of moisture in the air.
Be able to describe the advantages of using dew point temperature as an indicator of moisture in the air.
SUGGESTED PROCEDURE:
1. Review the terms following terms before initiating lesson:
2. Introduce the mathematical terminology and equations used for the lesson:
3. Demonstrate with an empty cup of water and asking how much potential content does the cup have. Fill the cup partially full and ask how much actual content is in the cup. This would give a concrete example of the relationship of relative humidity.
Strategies/Activities
2. Download excel spreadsheet of 15 minute data designed for this activity at the following link: http://www.kymesonet.org/docs/DataSet_1.xls
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Note: This data set has been simplified for your students. Explore the data tab to find an answer key (DataSet_1a), and a complete list of data associated with this Lesson (DataSet_1c). Graph paper from http://www.printfreegraphpaper.com/ is available under the data tab as well.
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5. Compare any patterns you see or any trends that may continue.
SUGGESTED STUDENT ASSESSMENT:
EXTENDING THE LESSON:
In the winter, static charge sometimes makes a spark between your finger and a piece of metal. This occurs more frequently inside a house than outside a house. Can you explain why?
Can you name a situation when the relative humidity may be high, but there is little moisture in the air?
ADAPTIONS:
Challenged Learner:
Have these children chart their results on graph paper instead of the Microsoft Excel Software.
Challenging Learner:
Extend this lesson to a different area outside of Kentucky to the Mesonet Network in Oklahoma and have these students compare Kentucky and Oklahoma and their similarities and differences with their air temperature, relative humidity, and dew point temperature.
RELATED LINKS:
Adapted from Oklahoma Mesonet Site