Intro to Weather Clip

Weather by Brainpop

1) What cycle is the basis of our weather?

2) What causes precipitation to occur?

3) Where do storms usually occur?



Weather

Temporary behavior of atmosphere (what’s going on at any certain time)  Small geographic area  Can change rapidly

Weather

--The study of weather is

meteorology

--Someone who studies weather is called a meteorologist

  

Climate

Long-term behavior of atmosphere (100+ years) Large geographic area Very slow to change

90 o -60 o

POLAR

latitude Cool summers, cold year-round

Dry

TEMPERATE

60 o -30 o

latitude True Seasons Variety of climate patterns Moderate precipitation (rain/snow)

TROPICAL

30 o

- equator No winter, warm year-round High temp, rainfall, humidity

Climate Types by Brainpop

1.What is climate?

2.Where are tropical climates most likely to be?

3.What does “arid” mean?

What Factors Affect Weather & Climate?

1.

2.

3.

4.

The Sun The Water Cycle The Atmosphere The Ocean

How Does the Sun Affect Weather?

It warms the atmosphere & oceans It creates climate zones It keeps the water cycle going It affects weather patterns

The Water Cycle

All the water on the planet is recycled in this manner!

Parts of the Cycle

Evaporation

—Water going from a liquid to a gas (gains energy from the sun)

Parts of the Cycle

*Transpiration—evaporation of water from/out of plants. Locate this on the diagram!

transpiration

Parts of the Cycle

Condensation

—Water going from a gas to a liquid (cools or loses energy)  When this happens in the atmosphere, CLOUDS form.

Clouds by Brainpop

Parts of the Cycle

Precipitation

stay up.

—when water falls out the atmosphere. Forms when the water droplets in clouds become too heavy to

Precipitation

 Liquid water = rain Rain Clip  Frozen water = snow or sleet or hail

The Water Cycle Water Cycle by Brainpop

Water Cycle Advanced by Brainpop

The Water Cycle by Brainpop 1) What process must happen for clouds to form?

2) What is “collection”?

3) Name one way to conserve water.

How does the atmosphere affect weather?

The atmosphere is a mixture of gases that surrounds the Earth Has five different layers; each has different properties We’ll label them in just a minute… Air Temperature and Pressure change with altitude Weather occurs in the layer closest to Earth (troposphere)

Write in the labels!

Exosphere Thermosphere Ionosphere Mesosphere Stratosphere Troposphere Ozone layer

Earth’s Atmsophere by Brainpop 1. What is ozone?

2. What layer of the atmosphere does weather occur in?

3. What 2 gases compose the most of Earth’s Atmosphere?

Air Masses

= body of air with a certain temperature and

moisture level

Can be warm or cold Can contain a lot of moisture or not a lot of moisture

Fronts

= places where air masses meet 4 Types: Warm, Cold, Occluded, Stationary Each kind can bring different kinds of weather

Occluded Front: Stationary Front:

Science Saurus 221/222 & Reading a Weather Map Worksheet

How does Air Pressure affect weather?

How much the earth’s atmosphere is pressing down on us Measured with a BAROMETER If it CHANGES, then new weather is on the way: Falling Air Pressure = stormy weather coming Rising Air Pressure = fair weather coming Steady Air Pressure = no change is coming

Pressure Systems

Winds

= created from differences in air pressure Moves from areas of HIGH to LOW pressure Greater the difference in pressure, the FASTER the wind blows Measured with wind vanes and anemometers or you can estimate with the Beaufort Wind Scale ScienceSaurus 224/225

Beaufort Wind Scale

Global Winds

Thousands of kilometers long; can cause weather to move in different directions Jet stream, prevailing westerlies, doldrums, horse latitudes, trade winds

Big Winds Blowin’ Worksheet & Science Saurus Section 217

Global Winds

Caused by the temperature difference in different regions  Hot Tropical Regions—causes air to

rise

 Cold polar Regions—causes air to

sink

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

Big Winds Blowin’ Worksheet

Winds by Brainpop

1. What does warm air do?

2. What do you call winds that blow all the time in the same part of the world?

3. What are jet streams?

Relative Humidity

    Measure of the amount of moisture in the air compared to what the air could hold How “full” of water the air is Expressed as % 100% relative humidity = saturated air Relative Humidity Test Applet http://itg1.meteor.wisc.edu/wxwise/relhum/rhac.html

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

decreases

3. As air

cools

, relative humidity

increases

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 liquid b. dew will form on surfaces

Dew Point

c. cloud droplets will form in air

2. If dew point temp. is below freezing:

a. water vapor condenses as a solid b. frost on surfaces c. snow (or hail) in the air

Humidity by Brainpop

1. What single factor controls humidity?

2. What temperature air can hold the most water molecules?

3. What causes water to evaporate into the atmosphere?

R a i n b o w s     Caused by sunshine on raindrops White light (all colors) is refracted (bent) into colors as it enters and exits the drop To see a rainbow you must have the sun behind you and raindrops in the air Diagram:

Rainbow by Brainpop

How does the Ocean affect weather?

Ocean currents affect the temperature of the land they pass by Cold ocean currents = cooling effect Warm ocean currents = warming effect Temperature changes affect pressure – which then creates WINDS Winds blow this cooling or warming effect over the land http://earth.rice.edu/MTPE/hydro/hydrosphere/topics/Ocean_Atm_Circ_ElNin o.mov

http://www.wunderground.com/MAR/

Science Saurus Sections 203-204-205-206

Advanced Weather by Brainpop Violent Weather

Thunderstorms

Requires a mature cumulonimbus cloud

Signs

a.

b.

Sudden reversal of wind direction Noticeable increase in wind speed

Thunderstorms

Possible weather:

a. heavy rains (flash floods) b. lightning (forest fires) c. thunder (frightens animals) d. hail (crop damage) e. tornadoes f. strong, gusty winds Thunderstorm by Brainpop

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Safety Rules

Stay indoors Prepare for lightning, strong winds Listen on radio/TV for tornado watch/warning Thunderstorms don’t last long

Lightning Storm

Cumulonimbus cloud becomes electrically charged and ground below has opposite charge

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 cloud Bright light is caused by glowing air molecules heated by the current Lightning follows the path of least resistance (easiest way to positive) Lightning rod offers lightning an easy, safe path to the ground (+)

Thunder is the shock wave caused by the explosive expansion of heated air Sound travels @ about 1100 ft/sec in air 5,280 ft in one mile Distance 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)

Types of Lightning

Streak or bolt

a.

b.

Single or branched lines of light Common in Puget Sound area

Sheet

a. shapeless flash over wide area b. is cloud-to-cloud bolt hidden by the clouds c. common in Puget Sound area

Other types of lightning

a. heat, ribbon, beaded (types of bolt) b. ball (only other have) shape lightning can

Safety rules for lightning storms

        Stay indoors Stay away from anything that conducts electricity (stove, sink, telephone, TV) Get out of the water and off of small boats Stay away from open doors, windows, fireplaces Stay in your car (very safe place to be) Don’t stand under lone trees or in open places Avoid hilltops If 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

Lightning Strikes (17 minutes) Stories of people hit by lightning

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Tornado

(a.k.a twister, cyclone)  Counterclockwise column of rotating air extending from cumulonimbus cloud Per square foot, is the most destructive atmospheric event Rated by wind speed (F1 to F5) “Tornado season” = April, May, June Tornadoes that form over water are called “waterspouts”

Behavior of a tornado is unpredictable Typical tornado will: 1. Occur between 3-7 pm 2. Travel 4 miles 3. Be 300-400 m wide 4. Travel 25-40 mi/hour 5. Have wind speeds up to 300 mi/hr 6. Produce extremely low pressure 7. Be dark due to debris picked up Tornado by Brainpop

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Safety Rules

Rule #1: Take immediate action!

Move away from tornado’s path Tornado’s path Move away at a right angle

Lie flat in nearest ditch, etc.

At home a. open windows, doors b. seek shelter in basement or under heavy table in middle of house On the trail of a tornado

Tropical Cyclone

Nicknames

1. Atlantic: hurricane 2. SE Asia, Japan: typhoon 3. Australia: willy-willy 4. Indian Ocean: cyclone

Tropical Cyclone

Rated by wind speed (category 1 to 5) Starts and grows over warm ocean water Composed of bands of thunderstorms spiraling counterclockwise around a low pressure center

Characteristics

    Winds from 74-200 mi/hr a.

Contains an “eye” Hurricances by Brainpop Small region of low pressure b.

c.

d.

Several hundred miles wide Last many days (even weeks) Surrounded by highest winds Calm, peaceful, sunny weather Last for about 1 hour as hurricane passes by

Safety Rules

     Prepare for high winds a.

b.

Prepare for flooding (greatest source of damage) Up to 20 in. of rain Flooding by coastal water 3. Prepare for thunderstorms 4. Have on hand stored food, water, blankets, candles, matches, radio, etc.

5. Seek shelter Hurricanes Clip