Relative Humidity and Dew Point On NB 70

Relative Humidity and Dew Point

On NB 70 create lists of the words below based upon how YOU think they should be grouped. atmosphere air pressure condensation density Coriolis effect radiation temperature conduction humidity convection air mass evaporation dew point high precipitation low jet stream front prevailing winds lifted condensation level weather

https: //www. youtube. com/watch? v=7 GS 5 jl 4 n. Lek Meteorologist explains humidity.

Measuring Water Vapor • Water evaporates into the • Two commonly used air and becomes an everterms to express the present but variable amount of water vapor in component of the air are atmosphere. – relative humidity – dew point. • Water vapor is invisible just as oxygen and other gases are invisible. • The amount of water vapor in the air can be measured

Water Vapor • The amount of water vapor in air is referred to as humidity. • The ratio of water vapor in a volume of air relative to how much water vapor that volume of air is capable of holding is called relative humidity

Relative Humidity and Temperature • Temperature largely determines the maximum amount of water vapor air can hold (its capacity) • Warm air is capable of holding more moisture than cold air. • Relative humidity will increase or decrease if more water vapor is added. If the temperature of a volume of air increases, but the amount of water vapor does not, then relative humidity decreases.

Saturation • Relative humidity expresses the degree of saturation. (%) – Air with 100% relative humidity is saturated – less than 100% is unsaturated. • Saturation occurs when a given volume of air is cooled to some specific temperature, and it can hold no more water vapor. • The relative humidity of that volume of air becomes 100%, and saturation occurs.

Dew Point • Dew point is the specific temperature to which air must be cooled to become saturated by the water vapor already present in the air. • OR the temp that condensation occurs

Measuring Relative Humidity and Dew Point • To measure relative humidity you use a Sling Psychrometer or Hygrometer Sling Psychrometer

Quick Explanation • https: //www. youtube. c om/watch? v=S 8 Wxl 4 mc. J 8&list=PLjolw. Wg dk. Tf. Vudlnzpk. Kr. Ks. Hectj 5 WCO&index=3

Assessment Prompt 1’s: What is relative humidity? 2’s: What is dew point?

Relative Humidity Data Table and Equation Dry bulb – Wet Bulb = Difference You will use the dry bulb temperature and the difference of the two to find the relative humidity of the air

Dew Point Temperatures and Equation Dry Bulb – Wet Bulb = Difference in Temperature You will use the dry bulb temperature and the Difference to find the temperature at which air reaches its dew point.

Assessment Prompt Green: What are the steps to using the reference table to calculate RH? Gold: Be prepared to tell what your Green partner said.

Relative Humidity and Dew Point Review Video Clips Homocks Podcast https: //www. youtube. com/watch? v=5 Eb. DKEAy 5 tw http: //www. youtube. com/watch? v=2 J 89 Mxl. Pg. Q Create a Venn diagram that compares and contrasts relative humidity and dew point.

Relative Humidity and Dew Point Venn Diagram Review Examine your Venn diagram that was created yesterday. Compare your work to the work of others at your table. Make necessary changes. Add a written reflection to the bottom. Reflect upon the importance of relative humidity and dew point in weather forecasting. Also list any questions you still have about this topic

Assessment Prompt Green: Why are we studying these terms as we start our weather unit? Gold: What could be confusing about these terms?

Hommocks Earth Science Dept. How to use the reference tables. http: //www. youtube. com/watch? v=mipa. X 2 oxw. A Practice with problems showing dry and wet thermometers.

Connection to the Real World and Science Watch the video clip from meteorologist Ken Weathers. Focus on why he is interested in the dew point temperature. . http: //www. youtube. com/watch? v=lc. Dc 9 Zm x 6 SY

Lab Activity: Determining Relative Humidity and Dew Point

Assessment Prompt Green: Explain the principle behind using the sling psychrometer to determine relative humidity. Gold: When air temperature and dew point are close together, what can be expected?

Summarizer: Dear Student Letter Write a letter to an absent student telling him/ her the point of today’s lesson. Include the steps needed to determine relative humidity and dew point. Also make a real-world connection by stating the significance of our lesson to forecasting the weather.

Review before Test • What is lifted condensation level? How is this term connected to weather? • A parcel of air has a dry-bulb temp of 20 degrees C and a relative humidity of 44%. What is the dew point of this parcel of air? • Review the ways that clouds can form. • Review how heat is transferred.

After Test: Read in textbook pages 299 -306 Complete the 12. 1 note-taking worksheet