Download FACT

http://www.animationfactory.com/en/search/closeup.html?&oid=4951769&s=1&sc=1&st=209&q=weather&spage=1&hoid=f7cfb49e
9694c64d3e413b6c217b6da5
Severe Weather
Lesson 8-3
Lightning
lightning – a bright discharge of static electricity
http://science.howstuffworks.com/enlarge-image.htm?terms=lightning&page=2
http://science.howstuffworks.com/enlarge-image.htm?terms=lightning&page=1
http://science.howstuffworks.com/lightning-pictures9.htm
Lightning
http://science.howstuffworks.com/cloud.htm
What causes lightning?
• lightning is an electric current
• in a thundercloud many small bits of ice bump
into each other as they move around in the air
• collisions create an electric charge.
• whole cloud fills up with electrical charges
• positive charges or protons form at the top of
the cloud and the negative charges or
electrons form at the bottom of the cloud
• opposites attract, that causes a positive
charge to build up on the ground beneath the
cloud
• The grounds electrical charge concentrates
around anything that sticks up, such as
mountains, people, or single trees.
• charge coming up from these points eventually
connects with a charge reaching down from
the clouds and - zap - lightning strikes!
http://www.weatherwizkids.com/lightning1.htm
• How do you know if lightning
is nearby?
– If you see dark clouds, then
lightning could be present, but the
best thing you can do is to listen
for thunder.
– If you hear thunder, then you need
to go indoors or get in a car. Don't
be outside, where lightning could
strike!
– If your hair stands on end or your
skin starts to tingle, lightning
maybe about to strike. Get down
on your hands and knees and
keep your head tucked in.
– Do not lay flat, because it can give
lightning a better chance of strike
you.
http://www.weatherwizkids.com/lightning1.htm
Know the Facts
• A lightning flash is no more than one inch wide.
• What we see as a flash of lightning may actually
be four different strokes in exactly the same
place, one right after another. That's why
lightning appears to flicker.
• Lightning is approximately 54,000 degrees
Fahrenheit. That is six times hotter than the
surface of the sun!
http://www.weatherwizkids.com/lightning1.htm
Thunderstorm
Development:
At a cold front, warm moist air is forced
upward and cools. Water vapor cools forming
cumulus clouds (10 km high).
http://www.nasa.gov/images/content/118608main_thunderstorm.jpg
http://farm1.static.flickr.com/201/473920107_b9f018b76b.jpg
Droplets form when smaller droplets
fall through the clouds and collide
with other droplets and become
larger. They create a downward
motion of air which cause high
winds.
• Characteristics of Thunderstorm:
– severe thunderstorm - high winds travel
faster than 80 kilometers per hour and hail
more than 2 centimeters in diameter
– heavy rain
– lightning - electricity that occurs when
current flows between regions of opposite
electrical charge
– lightning (cloud to cloud, cloud to earth,
earth to cloud, approximately 28,000º C)
– thunder (lightning causes heat that causes
air to quickly expand causing a sound
wave)
• Results:
– flooding
– mudslides
– fires from lightning
– electrocuted people
– hail damage
– wind damage
http://www.abc.net.au/reslib/200811/r314467_1390002.jpg
http://newsimg.bbc.co.uk/media/images/42381000/jpg/_42381087_mudslide_ap416b.jpg
http://www.wrh.noaa.gov/tfx/hydro/FAW/HorseBridge.png
Tornado
http://www.janolby.se/mixedemotions/images/20060828191224_tornado-2.jpg
• Development:
– form from severe
thunderstorms
– upward moving air twists
when it reaches the top of a
cloud and meets winds
moving in different
direction
– begins to rotate more
quickly and continues to
pull more warm moist air
up the center
• Characteristics of Tornado:
– high winds
– funnel shaped clouds
• 200 m in diameter (20
classrooms long)
• last less than 10
minutes
• whirling winds
• narrow path
• moves over land
• gray or black in color
from debris it picked
up
http://upload.wikimedia.org/wikipedia/commons/1/1a/Dszpics1.jpg
http://www.howtosurviveit.com/tornado
• Results:
– very destructive
http://www.esri.com/industries/localgov/graphics/americus1-lg.jpg
http://www.cimms.ou.edu/~doswell/chasesums/pampa19.JPG
http://innerjoejoe.files.wordpress.com/2007/08/nwoodtornado2.jpg
http://www.nssl.noaa.gov/edu/safety/tornadoguide.html
Tornado Myths:
• MYTH: Areas near rivers, lakes, and mountains are
safe from tornadoes.
• FACT: No place is safe from tornadoes. In the late
1980's, a tornado swept through Yellowstone
National Park leaving a path of destruction up and
down a 10,000 ft. mountain.
• MYTH: The low pressure with a tornado causes
buildings to "explode" as the tornado passes
overhead.
• FACT: Violent winds and debris slamming into
buildings cause most structural damage.
• MYTH: Windows should be opened before a
tornado approaches to equalize pressure and
minimize damage.
• FACT: Opening windows allows damaging winds to
enter the structure. Leave the windows alone;
instead, immediately go to a safe place.
Tornado Jokes
• Whatever happened to the cow that was
lifted into the air by the tornado?
• Udder disaster!
http://media.photobucket.com/image/tornadoes/ahBOO555/tornadoes.jpg
A lower cloud base in the center of the photograph
identifies an area of rotation known as a rotating wall
cloud. This area is often nearly rain-free. Note rain in
the background.
http://www.nssl.noaa.gov/edu/safety/tornadoguide.html
Before thunderstorms develop, a change in wind
direction and an increase in wind speed with
increasing height creates an invisible, horizontal
spinning effect in the lower atmosphere.
http://www.nssl.noaa.gov/edu/safety/tornadoguide.html
Rising air within the thunderstorm updraft tilts
the rotating air from horizontal to vertical.
http://www.nssl.noaa.gov/edu/safety/tornadoguide.html
• An area of rotation, 2-6 miles wide, now extends
through much of the storm. Most strong and
violent tornadoes form within this area of strong
rotation.
June 7, 2007 Tornadoes and
Monster Hail
Fast moving supercell thunderstorms with damaging
winds, hail larger than 5 inches in diameter, and
tornadoes ripped across central and northeast
Wisconsin on June 7, 2007. Five tornadoes
touched down in central and northeast Wisconsin.
http://www.crh.noaa.gov/images/grb/events/070607/NEWI_map.jpg
Map of northeast Wisconsin and tornado tracks. Not
denoted on the map is an area of straight-line wind
damage in the Thunder Mountain area of western
Marinette County, caused by the same supercell that
produced the long-track tornado.
Damage at the Bear Paw Resort.
More damage at the Bear Paw
Resort.
This is what remained of a double-wide mobile home in the
town of Riverview. The owner heard the Tornado Warning
and went into the bathtub (circled in large view), and
escaped without a scratch!
Hundreds of trees were snapped or uprooted
along the path. Ten homes sustained at least
minor damage.
Tree damage on HWY J in Marathon Co.
NOAA's National Weather Service
Green Bay, WI Weather Forecast Office
2485 South Point Road
Hurricane
• Development:
– largest storm that
occurs on earth
– very large, swirling
– low pressure
system that forms
over tropical
oceans
– forms over large
bodies of water,
steady supply of
energy
– may go on for days
http://walton.ifas.ufl.edu/images/hurricane-ivan.jpg
• Characteristics of Hurricane:
– wind that blows at least 120 kilometers per hour
– many kilometers in diameter
– form over warm, tropical oceans where two
opposing winds meet and begin to swirl
– low pressure area forms in the middle of the
swirl and begins rotating
– warm, moist air is force up into the middle of
low pressure area
– air cools and moisture starts to condense
– air is pulled toward the center
– receives energy from warm water
– weakens when hits cool water or strikes land
• Results:
– very destructive
http://harfordmedlegal.typepad.com/photos/uncategorized/hurricane_damage1_3.jpg
http://www.companysj.com/v244/cuban-hurricane.jpg
http://www.doh.state.fl.us/disease_ctrl/epi/Epi_Updates/Epi_Weekly/Hurricane_Betsey.jpg
http://www.abc.net.au/reslib/200708/r170693_640606.jpg
Photo courtesy Weather.com, photographer Stuart Livingston
Destructive waves from Hurricane Opal (1995) at
the State Pier in Gulf Shores, AL.
Hurricane Katrina NASA GOES Satellite Image.
August 29th, 2005NASA/Goddard Space Flight
Center Scientific Visualization Studio
The eye of a hurricane is weak compared to
the surrounding eyewall. NOAA
Bibliography
Glencoe/McGraw-Hill Team. Teacher's for Use with Science
Interactions Course 3. 3rd ed. New York: Glencoe/McGraw-Hill,
1998. 80+.
"HowStuffWorks "How Lightning Works"" Howstuffworks "Science
Channel" 1998-2009. Discovery Communication. 27 Mar. 2009
<http://science.howstuffworks.com/lightning.htm>.
"Lightning: The Shocking Story--National Geographic Kids." National
Geographic - Inspiring People to Care About the Planet. 1996-2009.
National Geographic. 27 Mar. 2009
<http://www.nationalgeographic.com/lightning/>.
Wicker Crystal http://www.weatherwizkids.com/index.htmCopyright ©
2003-2008 Crystal Wicker