Intro to Weather Clip

Weather

Temporary behavior of atmosphere (what’s going on at

any certain time)

Small geographic area

1.) Can change rapidly

Weather

--The study of weather is 2.) meteorology

--Someone who studies weather is called a meteorologist

Climate

3.) Long-term behavior of atmosphere (100+ years)

Large geographic area

4.) Very slow to change

POLAR CLIMATE 90o -60o latitude

Cool summers, cold year-round

5.) Dry

TEMPERATE CLIMATE 60o-30o latitude

6.) True Seasons

Variety of climate patterns

Moderate precipitation (rain/snow)

TROPICAL CLIMATE 30o - equator

7.) No winter, warm year-round

High temp, rainfall, humidity

What Factors Affect Weather & Climate?

• 8.) The Sun

• The Water Cycle

• 9.) The Atmosphere

• The Ocean

Cloud Formation

Cloud Formation • 10.) Warm air rises (less

dense)

• Air will gradually cool. The air will begin condensing.

• These nuclei will collide with other nuclei, eventually forming a cloud.

Types of Clouds Low clouds- lying on or just above the surface (up to ~10,000 ft).

• Consist of stratoform (flat) clouds • cumuloform (puffy) clouds,

Types of Clouds Stratus: Cumulus:

Types of Clouds (Cont’d) Middle Clouds - extending from 10,000 – 20,000 feet above the

surface : - Consist of altoform (meaning a middle cloud) type clouds.

Altostratus: Altocumulus:

Types of Clouds (Cont’d) High Clouds - These clouds are wispy/crisp/featherlike in appearance,

and do not produce precipitation. : - Consists of mainly ice crystals suspended above 20,000 feet from the

surface. These clouds are wispy/crisp/featherlike in appearance, and do not produce precipitation.

Types of Clouds (Cont’d) Cirrus: Cirrostratus: Cirrocumulus:

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—when water falls out the atmosphere. Forms

when the water droplets in clouds become too heavy to stay

up.

Precipitation

Liquid water = rain

Frozen water = snow or sleet or hail

Rain Clip

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)

Troposphere Stratosphere

Mesosphere

Ionosphere

Exosphere

Thermosphere

Write in the labels!

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?

Rainbows

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_ElNino.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. Sudden reversal of wind direction

b. Noticeable increase in wind speed

c. Sudden drop in temperature

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

Thunderstorms

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. Single or branched lines of light

b. 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 shape lightning can have)

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

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

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

Several hundred miles wide

Last many days (even weeks)

Winds from 74-200 mi/hr

Contains an “eye”

a. Small region of low pressure

b. Surrounded by highest winds

c. Calm, peaceful, sunny weather

d. Last for about 1 hour as hurricane passes by

Hurricances by Brainpop

Safety Rules

Prepare for high winds

Prepare for flooding (greatest source of damage)

a. Up to 20 in. of rain

b. 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