Mrs. Passell’s Weather Test Reviewrevised 2.9.14

The test will assess your understanding of clouds, precipitation, water cycle, fronts, high & low pressure areas, weather maps, weather instruments, heat transfer & storms .

It will not cover the layers of the atmosphere or air as a mixture.

WHO’S STUDYING THE WEATHER?Besides Mrs. Passell’s students?

METEOROLOGISTS!TV weatherpersons usually don’t have a degree in meteorology, the study of weather.

CLASSIFYING TYPES OF CLOUDSClouds are classified by their shapes and their altitude. You will need to be able to identify stratus, cirrus, and cumulus clouds and describe the kind of weather each one brings.

COMMON TYPES OF CLOUDS.

STRATUS CLOUDS Stratus clouds are not

individual “units’. These are the lowest

clouds. They produce

widespread rain or snow that may last days longer than a thunderstorm.

Fog is a stratus cloud close to the ground.

CUMULUS CLOUDS Puffy clouds like the ones you

drew in first grade Fair weather clouds

CUMULONIMBUS CLOUDS• Bring heavy rains,

lightning, thunder• May bring violent

weather• Also called

Thunderheads

http://www.crh.noaa.gov/images/ilx/swop/clouds.jpg

CIRRUS CLOUDS• High altitude, thin

clouds• Wispy, like feathers• Made of ice crystals• Sometimes called

“mare’s tails”

http://www.met.tamu.edu/class/Metr304/Severedir/CirrusClouds.jpg

FRONTSAn AIR MASS is the large body of air that has the characteristics of the land over which it develops. The whole air mass will have the same temperature, pressure and humidity.

A FRONT is the place where two air masses meet.

SYMBOLS FOR FRONTS

think of cold pointy icicles

think of the warm sun rising in the east

- not on the test

think of a stationary exercise bike - - you’re pedaling but not going anywhere!

MOVEMENT OF FRONTS

The front is moving in the direction of the points or half-circles. Stationary fronts are stationary so they are not moving!

MOVEMENT OF FRONTSRemember that COLD AIR IS MORE DENSE than WARM AIR.

Because WARM AIR is less dense, it doesn’t push under the cold air. It rises up over it.

When the COLD AIR approaches warm air, it pushes under the warm air.

Think of a cotton ball (less dense warm air) approaching a stone (more dense cold air). Can’t push under, got to go over!

WARM FRONTRemember that warm air is less dense than cold air so it will slide up over the more dense cold air.

WARM FRONT

The weather is rainy or snowy as the front approaches and the temperature starts to rise.

Warm Front. Image Credit: NOAA; http://tinyurl.com/c3o9gtu

COLD FRONT

A cold front pushes under the less dense warm air. Violent storms can occur.

STATIONARY FRONTThe WARM FRONT and COLD FRONT come together along a stationary front. The weather will be unsettled and for a few days.

WATER CYCLE/ HOW CLOUDS FORM.

WATER CYCLE/ HOW CLOUDS FORMDuring CONDENSATION the moisture that has evaporated and becomes water vapor cools as it rises in the atmosphere. The water vapor condenses to form clouds. Water drops that form in the clouds fall back to earth as precipitation.WATER CYCLE FOR KIDS

Think about a cold window. If you breathe on the window, your warm breath will form water droplets on the cold surface.

PRECIPITATION : RAIN & SNOWRain – liquid water; most common form of precipitation

Snow - - Just like rain except it passes through layers of freezing air as it returns to Earth

PRECIPITATION : SLEET, HAIL & FREEZING RAIN

Sleet - - rain passes through cold air close to the groundHail - - ice crystals rise & fall within the thunder- cloud; when they become too large, they fall to EarthFreezing Rain – regular land that freezes when it lands on surfaces that are 32º or lower

ISOBARSThese lines connect places that have equal air pressure. The closer together the lines are, the stronger the winds will be.

HIGH PRESSURE AREAS

High pressure is indicated with an “H” The weather will be fair with clear skies & maybe some puffy cumulus clouds..

HIGH PRESSURE = rising barometric pressure

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LOW PRESSURE AREASLow pressure systems are marked with an “L”. Cloudy weather & precipitation is found in low pressure areas. The center of all storms, including hurricanes, are low pressure areas.

LOW PRESSURE =falling barometric pressure

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WINDSEnergy from the sun causes uneven heating of Earth’s surfaces. This causes winds.

http://astronomy.nmsu.edu/tharriso/ast110/convection3.gif

WINDSAir moves from areas of high pressure to areas of low pressure.

HURRICANE OR TORNADO?Tornadoes are very different from hurricanes even though they are windstorms that cause much destruction .

A hurricane is a large low pressure system that covers a wide area. A tornado is a a more localized storm that lasts a shorter amount of time.

http://www.phe.gov/Preparedness/planning/playbooks/hurricane/Pages/default.aspxhttp://graphics8.nytimes.com/images/2013/05/24/us/Tornado1/Tornado1-superJumbo.jpg

HURRICANESThese storms form along the warm tropical waters near the equator.

http://spaceplace.nasa.gov/hurricanes/

HURRICANESIf you could slice into a tropical cyclone, it would look something like this. The small red arrows show warm, moist air rising from the ocean's surface, and forming clouds in bands around the eye. The blue arrows show how cool, dry air sinks in the eye and between the bands of clouds. The large red arrows show the rotation of the rising bands of clouds.(http://spaceplace.nasa.gov/hurricanes/)

TORNADOA tornado forms from a thunderstorm. Warm moist air meets cool dry air. Changes in wind speed and direction at different altitudes cause the spinning to begin.

DROUGHTDrought occurs when there is little or no precipitation for a long time.

http://en.wikipedia.org/wiki/2012–2013_North_American_drought

HOW LARGE BODIES OF WATER AFFECT WEATHER

Large bodies of water hold their heat longer than areas of land far from water.

56 ° 68 °

WEATHER INSTRUMENT: ANEMOMETER*measures the speed of the wind;strong winds cause the cups to spin faster

WEATHER INSTRUMENT: BAROMETERmeasure air pressure in inches or mercury or millibars

WEATHER INSTRUMENT: HYGROMETER or PSYCHROMETER

measures the humidity (the amount of moisture in the air)

WEATHER INSTRUMENT: WEATHER VANE or WIND VANE

shows the direction the wind is blowing

Nev

it D

ilmen

WEATHER INSTRUMENT: THERMOMETER

measure the temperature

WEATHER INSTRUMENT: RAIN GAUGEmeasure the amount of rainfall

How Does Air Pressure Change With Altitude?

As you climb higher up the mountain the air pressure is less than down at sea level and it becomes more difficult to breathe.

HEAT TRANSFER: CONVECTION• When air or water is heated, the

molecules move faster and farther apart, reducing their density and causing them to rise.

• Cooler air or water molecules move more slowly and are denser than warm air or water. The cold air sinks down. When it warms up again, it will rise again.

• Remember the rising air helps sailplanes & eagles to soar.

HEAT ENERGY TRANSFER: CONDUCTION

http://commons.wikimedia.org/wiki/File:Cup_for_Heat_Conduction_2010-08-17.png

Conduction is heat transfer by direct physical contact. The object has to be touching the heat source!

Conduction can happen in solids, liquids and gases.

Example: An ice cube will melt in your hand because the heat from your hand is absorbed by the ice.

HEAT TRANSFER : RADIATION• Radiation is energy transfer through empty

space.• It travels in the form of light waves.• Sunlight is a form of radiation.

CONDUCTION, CONVECTION, RADIATION

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http://greenstarpanels.com/portfolio/heat-gain-loss-in-buildings/

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?Adapted from >Mr. B. FontaineMrs. J. PhippsMrs. C. KoopParts of this powerpoint were kindly donated to www.worldofteaching.com

SOURCESTornado> http://www.weatherwizkids.com/weather-tornado.htm

Drought > http://en.wikipedia.org/wiki/File:Current-USDM.gifhigh to low pressure > http://hsc.csu.edu.au/primary_ind/prim_ind_240/compulsory/AHCWRK201A/3264/pressure_cells.htm