21 The Water Cycle by Brainpop What process must happen for clouds to form?What is “collection”?Name one way to conserve water.
22 How does the atmosphere affect weather? The atmosphere is a mixture of gases that surrounds the EarthHas five different layers; each has different propertiesWe’ll label them in just a minute…Air Temperature and Pressure change with altitudeWeather occurs in the layer closest to Earth (troposphere)
23 Write in the labels! Exosphere Thermosphere Ionosphere Mesosphere Ozone layerStratosphereTroposphere
27 Exosphere - the outermost layer of the Earth's atmosphere, where atmospheric pressure and temperature are low. Ionosphere - the atmospheric layer between the mesosphere and the exosphere; it is part of the thermosphere. Mesosphere - the atmospheric layer between the stratosphere and the ionosphere. Stratosphere - the atmospheric layer between the troposphere and the mesosphere. The stratosphere is characterized by a slight temperature increase with altitude and by the absence of clouds. Thermosphere - the layer of the atmosphere located above part of the ionosphere (starting at the coldest part of the atmosphere) and below outer space; it consists of the exosphere and part of the ionosphere. Troposphere - the lowest layer of the Earth's atmosphere. The weather and clouds occur in the troposphere.
28 Earth’s Atmsophere by Brainpop . What is ozone?. What layer of the atmosphere does weather occur in?. What 2 gases compose the most of Earth’s Atmosphere?
29 = body of air with a certain temperature and moisture level Air Masses= body of air with a certain temperature and moisture levelCan be warm or coldCan contain a lot of moisture or not a lot of moisture
30 Fronts = places where air masses meet 4 Types: Warm, Cold, Occluded, StationaryEach kind can bring different kinds of weather
33 Science Saurus 221/222 & Reading a Weather Map Worksheet
34 How does Air Pressure affect weather? How much the earth’s atmosphere is pressing down on usMeasured with a BAROMETERIf it CHANGES, then new weather is on the way:Falling Air Pressure = stormy weather comingRising Air Pressure = fair weather comingSteady Air Pressure = no change is coming
36 Winds = created from differences in air pressure Moves from areas of HIGH to LOW pressureGreater the difference in pressure, the FASTER the wind blowsMeasured with wind vanes and anemometers or you can estimate with the Beaufort Wind ScaleScienceSaurus 224/225
38 Global WindsThousands of kilometers long; can cause weather to move in different directionsJet stream, prevailing westerlies, doldrums, horse latitudes, trade windsBig Winds Blowin’ Worksheet & Science Saurus Section 217
39 Global Winds Caused by the temperature difference in different regions Hot Tropical Regions—causes air to riseCold polar Regions—causes air to sink
40 Global Winds Also affected by Earth’s Spin Coriolis Effect = causes winds to curve to the right in the N. Hemisphere; to the left in the S. Hemisphere
42 Winds by Brainpop . What does warm air do? . What do you call winds that blow all the time in the same part of the world?. What are jet streams?
43 Relative HumidityMeasure of the amount of moisture in the air compared to what the air could holdHow “full” of water the air isExpressed as %100% relative humidity = saturated airRelative Humidity Test Applet
44 Relative Humidity Controlled by temperature 1. Warm air holds more moisture than cool air (more space for water vapor between air molecules)2. As air warms, relative humidity decreases3. As air cools, relative humidity increases
45 Dew Point=Temperature at which the air is saturated (100% relative humidity)Several events can occur when the dew point temp. is reached:1. If dew point temp. is above freezing:a. water vapor condenses as liquidb. dew will form on surfaces
46 Dew Point c. cloud droplets will form in air 2. If dew point temp. is below freezing:a. water vapor condenses as a solidb. frost on surfacesc. snow (or hail) in the air
47 Humidity by Brainpop . What single factor controls humidity? . What temperature air can hold the most water molecules?. What causes water to evaporate into the atmosphere?
48 Rainbows Caused by sunshine on raindrops White light (all colors) is refracted (bent) into colors as it enters and exits the dropTo see a rainbow you must have the sun behind you and raindrops in the airDiagram:
50 How does the Ocean affect weather? Ocean currents affect the temperature of the land they pass byCold ocean currents = cooling effectWarm ocean currents = warming effectTemperature changes affect pressure – which then creates WINDSWinds blow this cooling or warming effect over the land
55 Thunderstorms Requires a mature cumulonimbus cloud SignsSudden reversal of wind directionNoticeable increase in wind speedSudden drop in temperature
56 Thunderstorms Possible weather: a. heavy rains (flash floods) b. lightning (forest fires)c. thunder (frightens animals)d. hail (crop damage)e. tornadoesf. strong, gusty windsThunderstorm by Brainpop
57 Safety Rules Stay indoors Prepare for lightning, strong winds Listen on radio/TV for tornado watch/warningThunderstorms don’t last long
58 Lightning StormCumulonimbus cloud becomes electrically charged and ground below has opposite charge
60 Lightning stroke: flow of current thru air (a poor conductor) from the – to the + Lightning can flow from cloud to ground, cloud to cloud, and from ground to cloudBright light is caused by glowing air molecules heated by the currentLightning follows the path of least resistance (easiest way to positive)Lightning rod offers lightning an easy, safe path to the ground (+)
61 Thunder is the shock wave caused by the explosive expansion of heated air Sound about 1100 ft/sec in air5,280 ft in one mileDistance from you to lightning = number of seconds between seeing the flash and hearing the thunder divided by 5.(5,280 ft / 1100 ft/sec = 5 seconds)
62 Types of Lightning Streak or bolt Single or branched lines of light Common in Puget Sound area
63 Sheet a. shapeless flash over wide area b. is cloud-to-cloud bolt hidden by the cloudsc. common in Puget Sound area
64 Other types of lightning a. heat, ribbon, beaded (types of bolt)b. ball (only other shape lightning can have)
65 Safety rules for lightning storms Stay indoorsStay away from anything that conducts electricity (stove, sink, telephone, TV)Get out of the water and off of small boatsStay away from open doors, windows, fireplacesStay in your car (very safe place to be)Don’t stand under lone trees or in open placesAvoid hilltopsIf your hair stands on end, or your skin tingles, drop to the ground but try to keep as little contact with the ground as possible
66 Stories of people hit by lightning Lightning Strikes(17 minutes)Stories of people hit by lightning
67 Tornado (a.k.a twister, cyclone) Counterclockwise column of rotating air extending from cumulonimbus cloudPer square foot, is the most destructive atmospheric eventRated by wind speed (F1 to F5)“Tornado season” = April, May, JuneTornadoes that form over water are called “waterspouts”
68 Behavior of a tornado is unpredictable Typical tornado will: 1. Occur between 3-7 pm2. Travel 4 miles3. Be m wide4. Travel mi/hour5. Have wind speeds up to 300 mi/hr6. Produce extremely low pressure7. Be dark due to debris picked upTornado by Brainpop
69 Move away at a right angle Safety RulesRule #1: Take immediate action!Move away from tornado’s pathTornado’s pathMove away at a right angle
70 Lie flat in nearest ditch, etc. At home a. open windows, doors b. seek shelter in basement or under heavy table in middle of houseOn the trail of a tornado
71 Tropical Cyclone Nicknames 1. Atlantic: hurricane 2. SE Asia, Japan: typhoon3. Australia: willy-willy4. Indian Ocean: cyclone
72 Tropical Cyclone Rated by wind speed (category 1 to 5) Starts and grows over warm ocean waterComposed of bands of thunderstorms spiraling counterclockwise around a low pressure center
73 Characteristics Several hundred miles wide Last many days (even weeks) Winds from mi/hrContains an “eye”Small region of low pressureSurrounded by highest windsCalm, peaceful, sunny weatherLast for about 1 hour as hurricane passes byHurricances by Brainpop
74 Safety Rules Prepare for high winds Prepare for flooding (greatest source of damage)Up to 20 in. of rainFlooding by coastal water3. Prepare for thunderstorms4. Have on hand stored food, water, blankets, candles, matches, radio, etc.5. Seek shelterHurricanes Clip