Evaluation copy. Air Temperature and Relative Humidity. computer OBJECTIVES MATERIALS PRE-LAB QUESTIONS

Transcription

1 Air Temperature and Relative Humidity Computer P2 If you live in a mid-latitude region, you may notice changes in relative humidity from season to season. Summers tend to be humid, while winters are drier. Besides changes in relative humidity between seasons, changes can be observed throughout one day, and that is the purpose of this experiment investigate the relationship between relative humidity and temperature over a 23- hour period. OBJECTIVES In this experiment, you will Use a Temperature Probe and Relative Humidity Sensor to collect and analyze outdoor air temperature and relative humidity for 23 hours. Determine if there is relationship between relative humidity and air temperature. MATERIALS computer Vernier LabPro Logger Pro Vernier Relative Humidity Sensor PRE-LAB QUESTIONS Temperature Probe 1.5 m metal rod right angle clamp utility clamp 1. Sketch a graph of air temperature for a 24 hour period. What time of day would you expect to be the hottest? When would you expect it to be coldest? Evaluation copy Earth Science with Vernier P2-1

2 Computer P2 2. Sketch a graph of relative humidity for the same 24 hour period. Do you expect the relative humidity to change? If so, what time of day would you expect to be the most humid? When would you expect it to be the least humid? 3. Use an almanac, the weather forecast, or the Internet to determine when sunrise and sunset will occur during the experiment. Enter those times into the data table. PROCEDURE Figure 1 Note: You must use Logger Pro software and a LabPro to collect data remotely. Logger Lite and Go! products do not support remote data collection. 1. Connect the Relative Humidity Sensor to Channel 1 of LabPro and the Temperature Probe to Channel 2. Make sure that fresh batteries have been installed in LabPro. Start Logger Pro and open the file P2 Air Temp-Rel Humidity from the Earth Science with Vernier folder. 2. Choose Remote LabPro Setup from the Experiment menu. A summary of your setup will be displayed. 3. Disconnect the computer cable from LabPro. Important Note: Be very careful not to press the START/STOP button on LabPro until you are ready to begin collecting data. 4. Carry the LabPro, sensors, and metal rod outside. Choose a location that will be in the shade throughout the daylight hours. Push the metal rod into the ground so it is straight up and down. P2-2 Earth Science with Vernier

3 Air Temperature and Relative Humidity 5. Use a right angle clamp to secure the Temperature Probe one meter above the ground. Use the utility clamp to secure the Relative Humidity Sensor to the metal rod and just below the Temperature Probe. 6. Press the START/STOP button to start data collection. Record the time of day to the nearest hour in the data table. Enter the time using a clock format of hour and AM or PM, for example 11:00 AM. Day 2 7. At the end of 23 hours, collect the LabPro, sensors, and metal rod and take them back to the computer. Note: Do not attach LabPro to the computer until Step Start Logger Pro and open the file, P2 Air Temp-Rel Humidity. 9. Reattach LabPro to the computer. If a Remote Data Available window appears, simply click the YES button and choose to retrieve remote data into the current file. If a window does not appear when the interface is reconnected, choose Remote Retrieve Remote Data from the Experiment menu. DATA Sunrise Sunset Time of day that data collection began Hour from Start (hr) Time of Day (Hour AM/PM) Temperature ( C) Relative Humidity (%) Highest temperature Lowest temperature PROCESSING THE DATA 1. Examine the data pairs on the displayed graph. Click the point with the highest temperature. Record that time in the Hour from Start column of the data table. Also record the corresponding temperature and relative humidity in your data table. Round your temperature data to the nearest tenth of a C and your relative humidity data to the nearest whole number. 2. Click the time with the lowest temperature. Record that time in the Hour from Start column of the data table. Also record the corresponding temperature and relative humidity in your data table. Round your temperature data to the nearest tenth of a C and your relative humidity data to the nearest whole number. 3. As the temperature of the air went down, how did the relative humidity change? Earth Science with Vernier P2-3

4 Computer P2 4. The above relationship is simply based on two data points. Determine if other data points show the same relationship. View a graph of relative humidity vs. temperature on Page 2 by clicking the Next Page button,. 5. Examine the graph of relative humidity vs. temperature. Do the data points show a trend? Describe in one or two paragraphs the relationship that you observe between the air temperature and relative humidity. The following questions might help you prepare your answer. When during the day was the relative humidity highest? When was it lowest? As the air temperature increased how did the relative humidity change? 6. (Optional) Print or sketch a copy of the graph of relative humidity vs. temperature as directed by your teacher. Your teacher may have you also make copies of the relative humidity vs. time and the temperature vs. time graphs. EXTENSIONS 1. Are the patterns that you observed repeatable? To answer this question, set up the experiment to collect data for two to three days. Compare the data from one day to the next. 2. Repeat the same experiment but collect the data inside a school or at your home. 3. Repeat this experiment at different times of the year. Compare your data for different seasons. P2-4 Earth Science with Vernier

5 Vernier Lab Safety Instructions Disclaimer THIS IS AN EVALUATION COPY OF THE VERNIER STUDENT LAB. This copy does not include: Safety information Essential instructor background information Directions for preparing solutions Important tips for successfully doing these labs The complete Earth Science with Vernier lab manual includes 33 labs, 6 projects, and essential teacher information. The full lab book is available for purchase at: Vernier Software & Technology S.W. Millikan Way Beaverton, OR Toll Free (888) (503) FAX (503) info@vernier.com