Quiz Chapter 24 1 Sublimation 2 Latent heat

Quiz Chapter 24 1. Sublimation 2. Latent heat 3. Humidity 4. Saturated 5. Relative humidity 6. Psychrometer 7. Hair hygrometer 8. Specific humidity 9. Dew point 10. Dew

Turn to page 482 9/29/2020 describe how relative humidity is measured

This is due at the end of class Warm up question: How does relative humidity measure humidity Exit: What is a dew point Homework: Questions on page 483 – due 2/4

Essential Question Describe what happens when the temperature of air decreases at or below the dew point Homework Questions on page 483 – due 2/4.

1. Sublimation 2. Latent heat 3. Humidity 4. Saturated 5. Relative humidity 6. Psychrometer 7. Hair hygrometer 8. Specific humidity 9. Dew point 10. Dew 11. Frost Chapter 24 12. Condensation nuclei 13. Convective cooling 14. Adiabatic 15. Advective cooling 16. Stratus clouds 17. Cumulus clouds 18. Cirrus clouds 19. Radiation fog 20. Advection fog 21. Upslope fog 22. Steam fog

Chapter 24 23. Sleet 24. Glaze ice 25. Hail 26. Coalescence 27. Supercooling 28. Freezing nuclei 29. Cloud seeding 30. Rain gauge • Video Link • experiments

Chapter 24 Section 1 Objectives • Explain how water vapor enters the air. • Explain the meaning of humidity and describe how it is measured. • Describe what happens when the temperature of air decreases at or below the dew point.

Notes chapter 24 section 1 • Atmospheric Moisture • Water in the air is • called water vapor: it is tasteless, odorless, and invisible gas Water in the air can also be in the form of ice or water droplets

Notes chapter 24 section 1 • Heat energy and water • Water in the form of ice is • • held in a CRYSTALLINE STRUCTURE Evaporation occurs when water molecules rotate and vibrate fast enough to overcome forces of attraction Can ice become vapor without first becoming water? – Sublimation: process where water in a solid form (ice) goes directly to a gas phase

Notes chapter 24 section 1 • Heat energy and water • Though most water enters atmosphere through EVAPORATION, some water does enter through SUBLIMATION – Where does most sublimation occur? (hint: where is there a lot of ice? ? ? ) • Latent Heat: “Hidden” heat – Given off during evaporation – Taken out during freezing

Notes chapter 24 section 1 • Humidity: amount of water in the atmosphere – When the air CANNOT hold anymore water, the air is considered to be SATURATED • The higher the temperature of air – THE MORE WATER IT CAN HOLD – As the temperature decreases, so does the ability of air to hold water vapor

Notes chapter 24 section 1 • Relative Humidity is a RATIO MASS OF WATER IN AIR POTENTIAL MASS OF WATER • Potential mass of water that air can hold changes with the temperature of the air – Hotter - more water vapor content – Colder – less water vapor content

Notes chapter 24 section 1 • Measuring Relative Humidity • Wet Bulb – Dry Bulb Method – Dry bulb takes temperature of air with the amount of moisture present – Wet Bulb takes temperature of air SIMULATING A SATURATED ATMOSPHERE – Using both measurements, estimate humidity based on Relative Humidity Chart • Tool: PSYCHOMETER

Notes chapter 24 section 1 • Specific Humidity • Express the amount of • water in the air in g/kg It is not affected by temperature or pressure.

Notes chapter 24 section 1 • Dew point • This is the temperature • • 9/29/2020 at which air is saturated with water. Below this temperature liquid or solid water forms. Dew may also form on a surface via condensation If the dew point is below freezing frost will form list the conditions that must exist for a cloud to form

Chapter 24 Section 2 Objectives • List the conditions that must exist for a cloud to form. • Identify the types of clouds. • Describe four ways fog may form.

Notes chapter 24 section 2 • Clouds and fog • Are visible water • 9/29/2020 droplets in the atmosphere Clouds and fog are the same, altitude is the only difference. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Cloud formation • The water needs • 9/29/2020 something to condense onto, dust. The air must be at or below the dew point to cause cloud formation or saturated. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Convective cooling • As air rises it expands • 9/29/2020 and cools, due to the release of energy. This process of cooling and heating to rising and falling air is called adiabatic list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Convective cooling 9/29/2020 • Warms at a steady rate of 10 C for every 100 M the air descends. The cooling is effected by the condensation process and averages. 70 C per 100 M the air rises. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Convective cooling • The level at which the • 9/29/2020 clouds form is called the condensation level. This starts at the bottom of the cloud and further condensation allow the clouds to form up. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Forceful Lifting • Can be caused by air • 9/29/2020 moving over a mountain range. It can also be caused by warm air pushing over a cold air mass. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Temperature changes • The mixing of two or more moist air masses with different air temperatures may be enough to get below the dew point. 9/29/2020 list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Advective cooling 9/29/2020 • This is when warm moist air passes over a cold body of water or land mass, the heat is absorbed (dropping below the dew point) and low clouds form or fog. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Classification of clouds • By form and altitude • Forms: Stratus, • 9/29/2020 Cumulus and Cirrus. Altitude groups: Low is up to 2, 000 M, Middle is 2, 000 to 6, 000 M and High is above 6, 000 M list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Stratus Clouds • Are sheet like or layered, they • • 9/29/2020 are low to the earth surface and cover large areas of the sky. Formed when warm air is above cool air, give very little rain. Two other types: nimbostratus are dark and give heavy rain or snow, altostratus form at middle latitudes and little rain list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Cumulus Clouds • Are the puffy or popcorn • 9/29/2020 clouds, if the form at the middle they are altocumulus and at lower levels are stratocumulus and cumulus. If there are strong rising winds a cumulonimbus forms and can produce thunder, lighting and rain. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Cirrus Clouds • These are the feathery or • 9/29/2020 curly clouds at high altitudes. Normally made of ice crystals, that can cause a halo to form around the sun or moon. list the conditions that must exist for a cloud to form

Notes chapter 24 section 2 • Fog • Radiation fog or ground fog forms • • 9/29/2020 close to the ground as it gives off the heat from the day, more common in valleys were the cold air can collect. Advection fog forms when warm moist air pushes over a colder surface. Upslope fog is cause by warm air moving uphill and steam fog is when warm air moves over a colder body of water. list the conditions that must exist for a cloud to form

Chapter 24 section 3 essential questions • Describe the various types of liquid and solid precipitation. • Compare the two processes that cause precipitation • Describe how rain may be produced artificially • Describe how precipitation is measured 9/29/2020 list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Precipitation 9/29/2020 • Moisture that falls from the sky; either as a liquid or solid. ( rain, snow, sleet and hail) list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Forms of precipitation • Liquid – rain • A drizzle – drops less • 9/29/2020 then. 5 mm are close together and fall slowly. Raindrops -. 5 mm to 5 mm, can be a mist to heavy rains as in a storm. list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Snow – most common • Forms of precipitation solid form. Smaller in size • • 9/29/2020 in lower temp because of lack of moisture. Sleet – rain freezes in the air as it falls to the ground. If it freezes when it hits the ground it forms sheet ice or glaze ice. list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Forms of precipitation • Hail – lumps of ice • 9/29/2020 that are spherical or irregular in shape. Form in normally in cumulonimbus clouds, rain gets pushed through a freeze layer and wind currents push it up and down several times. list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Causes of precipitation • Water droplets are • 9/29/2020 normally small enough to stay in the air. If the size increases 100 times from 20 micrometers, they will begin to fall list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Coalescence • Rain drop size is • • 9/29/2020 determined by the size of the nuclei. As droplets collide they get larger until it comes down as rain. Coalescences is how rain forms in the tropics. list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Supercooling • Water temps may go as • • 9/29/2020 low as -100 C. They do not freeze unless they have a freezing nuclei to attach to. Once the process starts, crystals form quickly and fall as snow or rain list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Cloud seeding • They add freezing nuclei • 9/29/2020 to the cloud like: silver iodine (from flares or burners) or powdered dry ice. Conflicting evidence on effect, it may someday help end droughts and control storms. list the conditions that must exist for a cloud to form

Notes chapter 24 section 3 • Measuring precipitation • Three types: a wide funnel • • 9/29/2020 attached to a cylindrical container, one that dumps when it reaches a certain level, and the last weighs the amount of water in the bucket. Only measure in one small area. Snow is measured by depth and water volume, average is 10 cm of snow per 1 cm of water list the conditions that must exist for a cloud to form