Finding Relative Humidity and Dewpoint

"Aim: How can we measure relative humidity? Topic: Unit 6 Meteorology. Main 
Idea: Measuring Relative Humidity. 1) What is a sling psychrometer?"

http://www.sewanhaka.k12.ny.us/cms/lib3/NY01001491/Centricity/Domain/1619/sling%20psychrometer.ppt