1. What is Relative Humidity and How is It Measured? Ms. De Los Rios Science Weather Factors 5.6

2. Vocabulary 5.6 1.Humidity- The amount of water vapor in a given volume of air. 2.Relative Humidity- the percentage of water vapor in the air compared to the maximum amount of water vapor that air can contain at a particular temperature. 3.Psychrometer- An instrument used to measure relative humidity.

3. What is Relative Humidity and How is it Measured? Pg. 180 What do wet day and hot day have in common? Water exists in different states: _______,_______, and ______. Gaseous form of water is _______ _________. Humidity is a measure of the amount of water vapor in the air. The ability of air to hold water vapor depends on the air’s temperature. Warm air can hold more water vapor than cool air.

4. As you can see warmer air can hold more water vapor. Relative Humidity

5. Relative Humidity pg. 181 Relative humidity is the percentage of water vapor in the air as compared to the maximum amount of water vapor the air can hold at a particular temperature. When the relative humidity is high there is a greater chance for precipitation. When the relative humidity is low there is a lower chance for precipitation. For example: at 10°C, 1 cubic meter of air can hold at most 8 grams of water vapor. If the air had 4 grams of water vapor, the relative humidity would be _____ percent. If the air had 8 grams of water vapor, the relative humidity would be ____ percent.

6. Relative Humidity This chart shows how relative humidity changes with temperature.

7. How Do You Measure Relative Humidity? Relative Humidity is measured with: psychrometer It has two thermometers, a wet-bulb thermometer and a dry-bulb thermometer. The bulb of the wet-bulb thermometer has a cloth covering that is moistened with water. When the psychrometer is “slung”, or spun, air blows over both thermometers. The wet-bulb thermometer is cooled by evaporation, its reading drops. The relative humidity can be found by comparing the temperatures of the wet-bulb and dry-bulb thermometers. Relative Humidity Online Tutorial

8. Relative Humidity Relative humidity is affected by temperature.

9. Relative Humidity Complete the crossword puzzle.