Determining the Dew Point

Tariq Khanstudy48@hotmail.com

Unit Goal

Weather

Temperature Relative HumidityDew Point

•Integrate concepts of Dew Point, Temperature and Relative Humidity•Relate Dew Point to Temperature and Relative Humidity•Integrate into Weather Module•Key Idea: The closer the Temperature to RH the lower the Dew Point

Inquiry based Experimental Design

Hypothesis

• Have students create experiment based on concepts

• Discuss experiment design with classmates

Experiment

• Does the experiment measure the Dew point?

• Teacher demonstrates then let students run experiment

• Have students think about their observations

Results

• Enter Data into Excel

• Plot the Graph• Analyze results• Compare findings

with other groups

Setting up the Experiment

The Following Apparatus is required to conduct the Experiment:•Regular Drinking Glass•Temperature Probe•Ice Cubes•Glass of Water•Access to computer (for Excel and Data Probe Recording)

Find the Dew Point

•The temperature probe will show decreasing temperature in its logging activity screen•Have the students touch the glass and observe the glass for formation of dew•The students should note the temperature at which dew forms

Data collection

•The left column indicates the temperature while the right indicates the time•Sample of the data collected through the probe, the Dew Point is indicated by the last temperature recording.

23.5622.81

22.3121.81

20.8119.75

19.0618.75

18.06 1716.63

16.1315.19

15.0614.44 14

13.6313.13

12.6305:18:57 PM

05:19:40 PM

05:20:24 PM

05:21:07 PM

05:21:50 PM

05:22:33 PM

Dew Point

Time•X-axis indicates the Temperature•Y-axis indicates passage of Time•Dew Point is reached at 12.63

Analysis and Interpretation

Students receive handout with following questions:

• Were the results what you expected them to be?• How did adding ice cubes to the water affect the temperature

of the water?• What is the time your Dew Point was reached? What was the

temperature?• How would you describe the results based on your data?• Create a graph based on your data, do you see a pattern?• Would you change anything about the way the experiment

was conducted? Any ideas for further research?

Integrating Ideas

Dew Point

Relative HumidityTemperature

Independent Inquiry

Students will look up the following topics:• Relative Humidity • Temperature

Relate lab to classroom activity:• Students will define the relationship between

Relative Humidity, Temperature and the Dew Point

Incorporating Technology

Students with exceptionalities or difficulty integrating complex ideas can be given a followup activity

The Dew Point calculator integrates all the ideas in our lab activity and lesson planning

http://www.dpcalc.org/

Conclusion

Learning Objectives:• Concepts Learned: Dew Point, Temperature,

Relative Humidity• Use of Technology: Data Probe, Excel, Data

Logging software, website (http://www.dpcalc.org)

• Inquiry based Learning: Students develop the idea for the lab, compare ideas with peers, analyze and interpret results

Video Presentation

Please click on the picture above to be taken to the YouTube video presentation demonstrating the lesson activity described