1 / 12

Intro

Objective 02/28/2012. Tell how dew point and humidity indicate the amount of water in the atmosphere. Intro. Benjamin Franklin posed this question for his students to figure out, can you?

anja
Download Presentation

Intro

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Objective 02/28/2012 Tell how dew point and humidity indicate the amount of water in the atmosphere. Intro • Benjamin Franklin posed this question for his students to figure out, can you? • Whence comes the Dew that stands on the Outside of a Tankard that has cold Water in it in the Summer Time?

  2. Measuring Water Vapor in the Air

  3. Measuring Water Vapor in the Air • Humidity • Amount of water vapor in the air • Higher the temperature = greater amount of water air can hold • Forecasters describe humidity in two ways: • Absolute humidity • Relative humidity

  4. Warm air holds more water than cold air

  5. Measuring Water Vapor in the Air • Absolute humidity • Measure of mass of water vapor in a volume of air • Example: • Absolute humidity of 2g/m³ = each cubic meter (m³) can hold 2grams of water vapor

  6. Measuring Water Vapor in the Air • Relative humidity • A ratio of water vapor that is in the air compared to the maximum amount of water vapor the air can hold at a certain temperature • Expressed as a percentage • Example: • Relative humidity is 50% = air is 50% full of water vapor

  7. Measuring Water Vapor in the Air • Saturated • When air is completely full of water vapor • Relative humidity is 100%

  8. Measuring Water Vapor in the Air • Factors Affecting Relative Humidity • Example: • Amount of water vapor • Temperature • More water vapor in air… • … higher the relative humidity • As temperature increases… • …relative humidity decreases

  9. Measuring Water Vapor in the Air • Measuring Relative Humidity • Psychrometer • Consists of two thermometers • Wet-bulb thermometer • Dry-bulb thermometer • Difference in temperature readings indicate amount of water vapor in the air

  10. Measuring Water Vapor in the Air • How a Wet-Bulb Thermometer Works • Wet-bulb thermometer covered with a damp cloth • If water evaporates quickly, relative humidity is low • If water evaporates slowly, relative humidity is high

  11. Objective 03/22/11 Describe how relative humidity is affected by temperature and levels of water vapor. Outro How much humidity would a desert have? (high or low) Explain.

More Related