Exploring Creation through Physical Science

Module 7 Notes

Factors that affect Earth’s Weather

Weather-the condition of the earth’s atmosphere (mostly the troposphere)

Climate-a steady condition that prevails day in and day out in a particular region of creation

Main factors influencing weather:

1. Thermal energy2. Uneven distribution of thermal energy3. Water vapor in the atmosphere

Clouds

(Fig 7.1 pg.158, know types from pictures for test)

Important “prefixes”:

Alto – added to a cloud that is found at a higher altitude

Nimbo or Nimbus-added to a cloud that is dark

4 Types:

1. Cumulus – “a pile” – fluffy clouds that look like piles of cotton (thunderclouds – cumulonimbus clouds)

2. Stratus- “layer” – typically low, formed when a mass of warm air is lifted slowly upward (nimbostratus clouds-get darker and darker until they produce precipitation)

3. Cirrus-“wisp” or “curl”-top of the troposphere, made completely of tiny ice crystals

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4. Lenticular- generally form by mountain regions

It is common to see crosses of these types of clouds:

Cirrocumulus clouds-look like cirrus clouds but still made of ice crystals not blown apart by the wind

Stratocumulus clouds-stratus clouds that form in puffs instead of a flat layer

Cirrostratus clouds-feathery appearance but form flat layers and are found higher than the stratus clouds

Thermal Energy

Insolation-light that comes to earth-“incoming solar radiation”

Aphelion – point at which the earth is farthest from the sun (earth receives about 3% less than its average amount of insolation

Perihelion-earth is closest to the sun and it gets about 3%more insolation than average

*typically more insolation means temp is warmer

The earth’s axial tilt is the REASON for the seasons we experience

Basics of tilt: (draw diagram and fill in notes from class)

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**add amount of sunlight to diagram, and which hemisphere points to sun

Orbit of the earth ONLY determines:

1. When the seasons change2. The amount the insolation the earth receives

Uneven Thermal Energy Distribution

Wind – created from temperature difference between the equator and the poles

Three factors that complicate the wind patterns:

1. Changing air temperature (global effect) Change in temp creates global patterns (Fig. 7.6 & 7.7)

2. Coriolis Effect (global effect)

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The way in which the rotation of the earth bends the path of winds, sea currents, and objects that fly through different latitudes

i. Figure 7.8ii. If a missile is fired from the equator toward the poles

it will “bend” eastiii. If a missile is fired from the poles towards the

equator, it will “bend” west3. Local winds

Can effect global wind patterns Fig. 7.10

i. Sea breeze – land heats faster than water, cold air over water pressure increases, pushing cooler air toward land

ii. Land breeze – land cools, pressure increases and pushes cool air out over water

Air Masses

Air mass-a large body of air with relatively uniform pressure, temperature, and humidity

The basic types:

1. Arctic – very cold2. Polar – cold

a. Maritime polar(mP)- cold and moistb. Continental polar (cP)-cold and dry

3. Tropical – warma. Maritime tropical (mT)-warm and moist (tend to form over

ocean)

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b. Continental tropical (cT) – warm and dry

Weather front – a boundary between two air masses

Types:

1. Cold front-when cold air mass wedges UNDER warm air mass

Lifts warm aircumulus cloudsaltocumulus cloudscumulonimbus clouds

*typically cold fronts cause the most severe weather systems

*systems form quickly

2. Warm front – usually moves OVER a cold front

Warm air coolscirrus cloudscirrostratus cloudsaltostratus and stratus cloudsnimbostratus clouds

*less violent than cold fronts

*rain formed usually less heavy and lasts longer

3. Occluded front – when two air masses traveling in same direction collide (cold air masses are faster than warm air masses)

*Usually formed when warm front traveling over a cold air mass

*starts slow and steady rain, turning into heavy and severe weather

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Module 8: Weather & Its Prediction

Precipitation

Types: rain, sleet, snow, drizzle, hail, dew or frost

Theories on how rain is formed:

1. Bergeron process Cold clouds with temps remaining below freezing Icicles grow larger, then fall, as fall they warm and become

rain or stay a colder form based on temperature Lots of evidence: i.e. – mountain regions can get snow at

high altitude and rain in valley below, all from same cloud2. Collision-coalescence process

Warm clouds Cloud contains many water droplets that have condensed

on cloud-condensation nuclei Droplets stick together, can continue to grow based on

amount of updrafts, until too big and drop

Sleet – ice pellets that pile up or melt when hitting the ground

Freezing rain-fall through a layer of air that is just at or slightly below freezing –result in raindrops that do NOT freeze until they hit something solid

Dew Point – temp at which dew forms and depends on:

1. Pressure2. Humidity

*higher pressure and humidity the higher the dew point

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Thunderstorms

Updraft – a current of rising air (how ALL thunderstorms start)

Stages:

1. Cumulus stage – rapidly growing cumulus cloud begins to form Lasts less than 20 minutes So much moist air pushed up into the troposphere it forms

a TALL cumulonimbus cloud Updrafts that continue to get stronger

2. Mature stage-contains heavy rain, thunder, lightning, strong winds and sometimes hail

Rain falls, causing winds to blow downward (some very strong, up to 170 mi/hr)

Both updrafts and downdrafts occur Usually lasts less than 30 minutes

3. Dissipation stage-final stage, where rain gets lighter and lighter Downdrafts only Downdrafts get less and less powerful

Thunderstorm cell – one updraft system and one resulting thundercloud (some thunderstorms have many of these cells)

Lightning & Thunder

Insulator- a substance that does not conduct electricity very well

Process of cloud-to-ground lightning:

1. A TALL and large cumulonimbus cloud forms2. As ice crystals fall through the cloud causing “glancing

collisions”, (creating electrical charge)8

3. A charge imbalance in the cloud causes the charge to build up on the ground

4. Positive charges in the ground attract some negative charges – forming a stepped leader

5. The closeness of the negative charges forces the positive charges up, making the return stroke (responsible for most of the light and sound of lighting)

6. Return stroke causes booming sound of thunder – caused by the intense heating that results when charges push their way through air (over 50,000 degrees F). superheated air rushes outwards in waves, forming sound waves we hear as thunder

Cloud-to-cloud Lightning or sheet lightning:

most common in thunderstorms (we still hear thunder from this lightning, though we may not see it)

only conducts between clouds, does not touch ground

Tornadoes

Stages:

1. Whirl stage- updraft of air forming a cumulonimbus cloud begins being hit by winds blowing in different directions at higher altitudes

Winds start rotating horizontally and combine with updraft to form a vortex – funnel of air whirling both around and up

2. Organizing stage – when funnel of air touches the ground, begins forming a solid base and begins sucking up debris

3. Mature stage – once the funnel has darkened in color from the debris, this is the most destructive stage

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4. Shrinking stage- begins getting smaller as vortex loses force to hold together

5. Decaying stage-weakens to where it is no longer visible and slowly dying out

*always see thunderstorm conditions before a tornado and it will “hang” from a cumulonimbus cloud

Hurricanes

Tropical cyclones – proper name for hurricanes

Stages:

1. Tropical disturbance – warm, moist air causing high rate of condensation and updraft, causing a pocket of low pressure leading to a vortex of whirling winds

2. Tropical depression – sustained speed of 23 mi/hr3. Tropical storm-sustained speed of 39 mi/hr4. Tropical cyclone-winds reach 74 mi/hr

*difference is only the wind speed

*there are 5 categories to a hurricane (also based on winds reached)

Eye-most pronounced feature of a hurricane and area of low pressure – forms a “calm area”

Eye wall – at the edge of the eye, whirling clouds and rain that can be several miles high

*spin counterclockwise in the Northern Hemisphere

*spin clockwise in the Southern Hemisphere

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**to form hurricanes need: warm, moist air AND where the Coriolis effect is most pronounced (this combo is between 10 and 20 degrees north or south of the equator)

BE able to INTERPRET a map like Fig. 8.10 OR map on Pg.202

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