Measuring relative humidity Use a dry bulb, a wet bulb and a table to determine the % of water Vapor the air contains. These instruments are called a psychrometer. psychrometer

Measuring Humidity Lab Activity Use the dry-bulb thermometer to measure and record the room temperature. Wrap gauze around the bulb of the 2nd thermometer and fasten it with a rubber band. Dip the gauze-wrapped wet-bulb into room temperature water. Fan the bulb until the temperature stabilizes. Record the temperature. Calculate the difference between the dry-bulb & wet-bulb temperatures. Use Appendix A (pg 704) in the textbook to determine the Relative humidity in the location you tested. Pre-Lab and Lab overview Choose a location to measure the relative humidity. Record the areas where your classmates will be testing. On the back, make a prediction where you believe the highest and lowest relative humidity will occur. (#1 on back) Run the lab and record your measurements and error on the back of this sheet (#2). Consider and write possible errors in your measurements. 5. Compare your results with the class and on the back write where the actual high and low occurred. Why do you think this was? (#3 on back) Hallway door Backroom

Highest relative humidity: Lowest relative Humidity: 2. Data Prediction Where in the testing area do you think the highest and lowest relative humidity will occur? Highest relative humidity: Lowest relative Humidity: 2. Data Record your obtained data. Dry bulb temp. _______________ Wet bulb temp. ______________ Relative Humidity _______%____ Difference _______ ___________ 3. Error During your testing for relative humidity, write notes concerning error within your experiment. 4. Results After comparing your results with the class, where was the lowest and highest humidity's in the testing area? H: L: 5. Reasoning: Why do you think the high and low were recorded where they were?