Goal 2.5. The Atmosphere

Transcription

1 Goal 2.5 The Atmosphere

2 Lesson 1 Atmospheric Basics

3 Think About It Why would it be a bad thing if the atmosphere was mostly oxygen?

4 Focus Question What is the structure and function of the atmosphere?

5 Atmospheric Composition Nitrogen 78% Oxygen 21% Argon -.93% Carbon Dioxide -.03% Water Vapor -.0 to 4% Trace Gases

6 Key Atmospheric Components Oxygen Gas Living things need oxygen to break down food for energy

7 Carbon Dioxide Gas Minor role in absorbing heat plant fertilizer Key Atmospheric Components

8 Key Atmospheric Components Ozone Gas Absorbs ultraviolet radiation from the sun

9 Key Atmospheric Components Water Vapor Gas Major role in absorbing heat source of clouds, rain, and snow

10 Key Atmospheric Components Water Liquid The source of rain Singing in the Rain!

11 Key Atmospheric Components Ice Solid Makes up snow, sleet, and hail Legendary Vail Powder!

12 Key Atmospheric Components Dust and Salt Solids Provide a solid surface for water vapor to condense around (so that clouds can form) See next slide Salt Spray from Waves Dust Storm

13 Condensation Nuclei

14 The Structure of the Atmosphere

15 The Structure of the Atmosphere The Troposphere Description 0-11 km highest air pressure Contains most of the gases of the atmosphere Objects Found There Weather life forms jets

16 The Structure of the Atmosphere The Stratosphere Description km Molecular heat rises due to the ozone absorbing heat Objects Found There Ozone layer Weather balloons

17 The Structure of the Atmosphere The Mesosphere Description km Molecular heat falls b/c there s not a whole lot here! Objects Found There Meteors (shooting stars) burn here

18 The Structure of the Atmosphere The Thermosphere Description km Molecular heat rises Objects Found There Ionosphere Auroras

19 The Auroras

20 The Structure of the Atmosphere The Exosphere Description Above 600 km Outermost layer Space! Objects Found There Some H and He Satellites

21 Temperature Variations with Altitude The layers are divided by temperature!

22 What Happens to the Sun s Energy?

23 Solar Fundamentals a. Radiation transfer of energy through space by visible light, ultraviolet radiation, and other electromagnetic waves Earth s surface is warmed by the sun s rays

24 Solar Fundamentals a. Conduction transfer of energy when molecules collide Air molecules above Earth s surface are warmed when they contact the warm surface of Earth

25 Solar Fundamentals a. Convection transfer of energy by flow of a heated substance Warm air rises, then cools and sinks

26 The Transfer of Heat in the Atmosphere Copy the diagram your teacher draws on the board!

27 Lesson 2 The State of the Atmosphere

28 Think About It What makes a hot air balloon float?

29 Focus Question What are the physical properties of the atmosphere that create weather?

30 Temperature of the Atmosphere 1. What is temperature? measurement - how rapidly or slowly molecules move 2. What is heat? transfer of energy that occurs because of a difference in temperature between substances a. Heat fuels atmospheric processes!

31 The Temperature of the Atmosphere b. The thermosphere is the hottest layer of the atmosphere but it feels so cold b/c even though molecules are moving very fast (which means they are very hot), they are so far apart that there would be no heat transfer. Astronaut Bruce McCandless II is feeling no heat!

32 The Temperature of the Atmosphere Write scales in margin o Fahrenheit o Boiling point 212 o Freezing point 32 o Absolute Zero -523

33 The Temperature of the Atmosphere o Celsius o Boiling point 100 o Freezing point 0 o Absolute Zero -273

34 The Temperature of the Atmosphere o Kelvin o Boiling point 373 o Freezing point 273 o Absolute Zero 0 o There are NO negative numbers on the Kelvin scale!

35 Absolute Zero Absolute zero is the temperature at which molecular motion theoretically stops! This does not occur anyplace in the universe.

36 The Temperature of the Atmosphere 3. Dew Point - temperature to which air must be cooled (at constant pressure) to reach saturation. o o o That is when dew is formed! The higher the dew point, more humid and uncomfortable the air. See next slide

37 Dew Point

38 3a. Water The vapor Temperature in the atmosphere of the becomes Atmosphere water droplets 3b. Dew point is also called condensation temperature b/c condensation is the process of water vapor changing into liquid water. (Remember the condensation nuclei?)

39 Vertical Temperature Changes 4. Altitude height above ground or sea level. a. Why is the temperature of the lower atmosphere cooler at higher elevations and altitudes? b/c it is farther away from the source of heat conduction from Earth s surface Individual air masses moving upward through the atmosphere will cool about 10 degrees C/1000 m.

40 Vertical Temperature Changes 4b. What is lifted condensation level? height at which condensation occurs The LCL often corresponds to the base of the clouds!

41 Air Pressure and Density 1. Density is mass per volume. As altitude increases (moving up through Earth s atmosphere), the density of the air... decreases 2. Air pressure is force exerted by molecules of atmosphere as they are pulled toward Earth s center. a. As altitude increases air pressure decreases

42 Air Pressure and Density 2b. Air at the bottom of the atmosphere has higher density and pressure because... of the greater mass of the atmosphere above you (it contains the most gases) Gravity is the force pulling all air molecules in the atmosphere toward Earth. This is similar to being at the bottom of the ocean with tons of water above you! We are accustomed to the high air pressure so it doesn t squash us.

43 Temperature-Density Relationship 1. The Relationship between Temperature and Density: Warm Air a. As temperature increases density decreases. b. Warm air is less dense and will rise. c. The upward movement of warm air lowers pressure. d. So, warm air rising causes low pressure.

44 Temperature-Density Relationship 2. The Relationship between Temperature and Density: Cold Air a. As temperature decreases density increases. b. Cold air is more dense and will sink. c. The downward movement of cold air raises pressure. d. So, cold air sinking causes high pressure.

45 Temperature Inversion 3. Definition when upper layers of troposphere are warmer than lower layers. Warmer layers are above colder layers. Cause on cold, clear, winter night, surface cools rapidly & becomes colder than air above it, resulting in upper layer being warmer! The warm layer can trap pollution or melt snow. d. Draw this

46 a. Cool air, which is denser, sinks. b. This forces the warm air, which is less dense to move upwards. c. Air moves from areas of high density to areas of low density. d. In its simplest form, wind can be thought of as air moving from an area of high pressure to an area of low pressure. 1. Creating Wind

47 Wind 2. The density imbalances that move air to produce wind are created by The unequal heating and cooling of Earth s surface 3. Wind is measured by anemometers (mph or kph) 4. Wind speeds increase at high altitudes b/c There are few to no obstacles there

48 Humidity Changes with Temperature 1. What is humidity? o The amount of water air can hold at a given temperature. This is a constant! 2. What is relative humidity? o The amount of water the air is actually holding compared to how much it can hold

49 Humidity Changes with Temperature 3. How much water vapor can a m3 of air hold at 25 degrees C? o 24 grams 4. How much water vapor can a m3 of air hold at 15 degrees C? o 13 grams 5. Why does the air hold more water at 25 degrees o than it does at 15 degrees C? Warm air can hold more water than cold air because it is less dense. 6. How much water (per m3) would the air hold in a room at 25 degrees C if the relative humidity was 50%? o 12 grams

50 Lesson 3 Moisture in the Atmosphere

51 Think About It Can you forecast the weather by looking at clouds?

52 Focus Question How are clouds formed and what does each type indicate about the weather?

53 Three Ways Clouds Can Form a. from convection currents b. from warm air rising over mountains (orographic lifting) c. when air masses of different temperatures meet

54 Cloud Formation Convection Currents

55 Cloud Formation Orographic Lifting Clouds form over a mountain.

56 Cloud Formation Frontal

57 Cloud Types Altitude Cirro- high Above 6000m Alto - middle Between m Stratus - low Below 2000m

58 Cloud Types Meaning Cirrus Latin for hair Wispy, stringy clouds

59 Cloud Types Cumulus Latin for pile or heap Puffy, lumpy clouds Altocumulus

60 Cloud Types Stratus Cirrostratus Halo around sun Latin for layer Featureless sheets of clouds Nimbostratus

61 Cloud Types Nimbus Latin for cloud Low, gray rain clouds Nimbostratus

62 Cloud Types Cumulonimbus Latin for puffy cloud Enormous rain clouds

63 The Water Cycle A Review! a. Water on Earth s surface will turn to water vapor in the process of o evaporation. b. Water vapor in clouds turns to liquid by o condensation. c. Rain, snow, sleet, or hail falls to Earth s surface as o precipitation.

64 Clouds

65 More Clouds!

66 Lesson 3 Cloud Model p. 288 Create 10 clouds. Get a piece of blue paper. Title it Clouds and write your name(s) on the bottom left. Draw the ground. Mark the altitude on left side. Draw a sun. Glue the clouds on and label them. Draw rain drops under the 2 nimbus clouds.