Transcript Describing Matter & Energy

Air Masses and Fronts
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Air masses are classified according to temperature
and humidity
4 major types of air masses:
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Maritime tropical: form over the ocean and bring in warm,
humid air
Continental tropical: form over dry land areas and bring in
hot, dry air (form only in the summer)
Maritime polar: form over the ocean and bring in cool,
humid air
Continental polar: form over land and bring in cool or cold
air
Fronts form when air masses meet and do not mix
because of densities (like oil and water)
Air Masses and Fronts
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4 major types of fronts:
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Cold front: forms when cold air moves underneath warm
air, forcing the warm air to rise (picture pg. 499) – how
does this affect local weather?
Warm front: forms when warm air moves over cold air
(picture pg. 500) – how does this affect local weather?
Stationary front: when warm and cold air masses meet,
however aren’t strong enough to move the other
Occluded Front: forms when a cold air mass and a cool air
mass come together, the warm air caught between them is
forced upward.
What is the difference between a cyclone and
anticyclone?
Air Masses and Fronts
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What two main characteristics are used to classify air
masses?
What is a front? Name and describe the 4 types.
What is a cyclone? What type of weather does it
bring?
Why do maritime polar air masses have more effect
on the West Coast than the East Coast?
Classify the 4 types of air masses according to
whether they are dry or humid.
Storms
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Thunderstorms form within large cumulonimbus
clouds, or thunderheads (this is when warm, humid
air rises rapidly)
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These produce strong upward and downward winds and
often occur in spring and early summer – late in the
afternoon when the ground is warm.
During the storm, positive and negative electrical charges
build up in clouds. The release of this energy is lightning.
Lightning jumps within clouds, between clouds or to the
ground
The lightning bolt produces thunder – how does this
happen?
To remain safe during thunderstorms, avoid touching metal
objects because they can conduct electricity from lightning
into your body
Storms
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Tornadoes develop in low, heavy cumulonimbus
clouds – why do these clouds sound familiar?
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These often occur in spring and early summer – late in the
afternoon when the ground is warm.
The safest place to be during a tornado is in the basement
of a well-built building
What is the difference between a tornado watch and a
tornado warning?
Storms
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Hurricanes form over warm water as a low-pressure
area or tropical disturbance and gets its energy from
the warm, humid air at the ocean’s surface
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Winds get stronger as the eye approaches, however the
eye of the storm is very calm
These are the longest lasting storms
Describe the damage that can occur from hurricanes –
what is a storm surge?
How do you remain safe during a hurricane?
Storms
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Describe a winter storm. What is lake-effect snow? How do
you remain safe?
What weather conditions are most likely to cause
thunderstorms and tornadoes?
What is the most common path for the hurricanes that strike
the United States?
What safety precautions should you take if a tornado is
predicted in your area? If a hurricane is predicted in your
area?
In the winter, cool, humid air from the Pacific Ocean blows
across the cold land of southern Alaska. What kind of storm
do you think this causes?
Floods
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The most dangerous weather-related event in the US.
Floods cause almost half of weather related fatalities.
Occur when so much water pours into a stream or
river that it overflows its banks and covers the land
on either side of the channel
Describe what happens when a flash flood occurs –
why are they so dangerous?
To stay safe during floods, move to higher ground.
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If your family is in a car, don’t drive across flood waters.
60 cm of fast moving water can sweep a car away.
Floods
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How can precipitation cause flooding?
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How can you stay safe during a flood?
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What is the difference between a flood watch and a
flood warning?
Name three tools that supply information used in
forecasting floods and providing flood information
(hint: look at the bottom of pg. 516)
Describe 2 weather situations in which you would
expect floods to occur.
Predicting Weather Change
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What does a barometer measure? Describe the
weather resulting in a change in the barometer.
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Describe what weather would occur if cumulus clouds
started growing larger and taller.
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Air pressure. Falling air pressure usually indicates an
approaching low-pressure area, possibly bringing rain or
snow
They would become cumulonimbus clouds, bringing
thunderstorms
Do meteorologists study meteors? Explain what their
job is.
Where do meteorologists get their information?
Predicting Weather Change
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Changes in technology for making predictions have
occurred in 2 areas: gathering weather data and
using computers to make forecasts.
Weather balloons can measure temperature, air
pressure and humidity while weather satellites
photograph Earth’s surface, clouds, storms, ice, snow
Computers start with weather conditions reported
from weather stations over a large area. They work
through calculations to predict the weather and
adjust their reports as new data comes in.
Predicting Weather Change
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Describe what happens with the winds and water
during an El Nino event.
What evidence do scientists use to predict an El
Nino?
Explain the word isobar – iso…? …bar? Think of
other words that use “iso” and “bar”.
Let’s look at a weather map in more detail
Predicting Weather Change
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What kinds of technology do meteorologists use to
help predict the weather?
Name at least 3 types of information you could get
from a weather map of your area.
What lines on a weather map connect points that
have the same temperature?
If you observe that air pressure is rising, what kind of
weather do you think is coming?