the winter solstice occurs on _______________________ sun north pole

The winter solstice occurs on

_______________________

sun

North Pole

Winter Solstice

• December 21• Sun rises south of east• Sun sets south of west• Sun’s altitude is lowest of year (longest

shadows)• Vertical rays (90*) at Tropic of Capricorn

(23.5*S)• NYS 9 hrs of daylight/North Pole=0

The summer solstice occurs on ______________________

sun

North Pole

Summer Solstice

• June 21• Sunrises north of east• Sunsets north of west• Sun’s altitude highest of year (shortest

shadows)• Vertical rays(90*) at Tropic of Cancer

(23.5*N)• NYS gets 16 hrs of daylight/North Pole=24

The equinoxes occur on

_________ & ___________

sun

North Pole

North Pole

Equinoxes

• March 21 & Sept 21• Sun rises due east• Sun sets due west• Vertical rays (90*) at the equator• 12 hours of daylight & 12 hours of

nighttime everywhere on Earth

• The true shape of the Earth is an

• Oblate sphere Slightly flat at poles

Bulges slightly at equator

• The best evidence for the roundness of the Earth is

• Photos from space

Other evidence of roundness• Ships that appear to

sink as they move over the horizon

• Polaris gets higher in the sky as you go north and lower as you move south

• Earth’s shadow on the moon during a lunar eclipse

The Earth appears to be

• Perfectly round

The driving force behind plate tectonics is

• Convection currents in the mantle

Convection currents are also found in the atmosphere and in bodies of

water

water

atmosphere

The youngest rocks are found at _____ and the older rocks are found near the ______

• The youngest rocks are at or near the mid-ocean ridge since new crust is being formed here.

• The older rocks are found closer to the edge of the continents.

Picture of mid-ocean ridge in Iceland.

The weather associated with a high pressure system is

• Clear, cool and dry (fair)

The circulation in a high pressure system (in northern hemisphere) is

Clockwise and

outward

The weather associated with a low pressure system is

• Cloudy, rainy and warm

The circulation in a low pressure system (in northern hemisphere) is

Counterclockwise and inward

How many seismograph stations are needed to find the epicenter?

3

The 500 rule says

• If over 500 add a 9• If below 500 add a 10

• Don’t forget the decimal and units (mb)

Minerals are composed of

• atoms

Rocks are composed of

• minerals

Minerals are

• Naturally occurring• Inorganic• Solids• Have definite chemical composition• Definite crystalline shape (internal

arrangement of the atoms)

Minerals are grouped by

• Chemical composition• The silicon oxygen tetrahedron is the most

common and it is pyramid shaped.

Physical properties of minerals(luster, cleavage/fracture and hardness) are determined by

the

• Internal arrangement of atoms

Rocks are classified by

• Their origins

Sedimentary rocks

• Compaction (burial) & cementation

Igneous rocks

• Melting & solidification of magma or lava

Metamorphic rocks

• Heat & pressure

Intrusive igneous rocks

• Form ______ and cool __________

Intrusive igneous rocks

• Form underground and cool slowly

• Large crystal sizes

Extrusive igneous rocks

• Form at the ________ and cool _______

Extrusive igneous rocks

• Form at the surface and cool quickly

• Small crystals, no crystals or vesicular (gas pockets)

Continental crust is made of ___ and ocean crust of _______

Continental crust is made of ___ and ocean crust of _______

• Granite (thick)• Basalt (thin)

Fossils are found in

Fossils are found in• Sedimentary rocks

Contact metamorphism

• Occurs when rocks come in contact w/magma or lava

Regional metamorphism

Occurs over a largearea is most oftenassociated with mountain building.

Most earthquakes and volcanoes occur at or near plate boundaries

P waves

• Primary waves (compressional or back & forth)

• Fastest• Arrive first• Travel thru solids and

liquids

S waves

• Secondary waves (side-to-side or shear)

• Arrive second• Travel slower• Travel thru solids only

Interior properties of the mantle and core are inferred from eq

waves• The inner core is solid due to intense

pressure• The outer core is liquid

Measuring Eq’s

• The Richter scale measures the amount of energy released by the eq

• The Mercalli scale measures intensity based on damage reports

3 plate boundaries

Divergent – move away& features mid-ocean ridges and riftvalleys, new crust is formed

3 plate boundaries

• Convergent – collide, old crust is destroyed– 3 types

• Ocean v. ocean = deep ocean trenches & volcanic island arcs ex. Japan, Aleutian Islands

• Continent v. ocean = ocean trenches, volcanic mountain chains ex. Cascades & Andes

• Continent v. continent = earthquakes & very tall mountain ranges ex. Himalayas

• Weathering is the breaking down of the rocks

• Erosion is the transportation of sediments

• Physical (mechanical) weathering breaks the rocks into smaller pieces

• Chemical weathering changes the composition

• Warm & humid (moist) climates favor chemical weathering

• Cold & humid climates favor physical weathering

• Weathering is slow in dry climates

Factors affecting weathering rates

• The more surface area the faster the weathering takes place

• Composition

Soils

• Form because of weathering & biologic activity

• The topsoil (a horizon) contains the darker soil and nutrients

• The subsoil (b horizon) is reddish in color due to the presence of clay particles that have been leached from the topsoil

• The c horizon is partially weathered bedrock

Agents of erosion

• running water – most effective & dominant• Glaciers• Wind• Ocean waves• Mass movement (creep, slump, landslide,

etc.• The major force behind all erosion is

gravity!

• The closer the isolines the steeper the slope.

• On a weather map, the closer the isolines the faster the wind blows.

Stream velocity depends on

• Slope (gradient)• Volume (discharge)• Shape of the channel

• The outside of the meander is faster and erodes

• The inside of the meander is slower and deposition occurs

• As the velocity of a stream increases, so does the particle size being carried

• As the discharge increases so does the velocity

• If the velocity decreases deposition occurs

A stream carries it load by

• Solution • Suspension• Bouncing & rolling & dragging• Abrasion is the process that rounds &

smoothes the pebbles because they are bouncing and banging into one another

Running water

• Sorts its material by size • In a horizontal cross-section the larger

particles are closer to shore and smaller particles are farthest from shore in deeper water

• In a vertical cross-section the larger material will be on the bottom and the smaller material on the top

River Valleys

• Are v shaped

Glacial valleys

• Are U shaped• Other evidence of glaciers

– Erratic (boulders)– Till – unsorted sediments– Eskers, kames, drumlins, moraines– Striations – parallel scratches in bedrock– Hanging valleys, kettle lakes & finger lakes– Lakes & drumlins tell direction of ice mov’t

Gravity deposits

• Are unsorted (talis)

• Rock layers that are resistant to weathering stick out or form cliffs while less resistant rock layers form valleys and are worn back

In undisturbed rock layers

• All layers are deposited horizontally first (law of original horizontallity)

• The oldest rocks are on the bottom (superposition)

• Faults, folds and intrusions are younger than the rocks they are found in (cross-cutting relationships)

• Fossils are at least as old as the rocks they are found in (flora & fauna)

Index Fossils

• Used to determine relative dates of rocks• Must be geographically widespread• Have a geologically short life span

Geologic Time

• Is divided into units based on the fossil record

• An unconformity is a buried erosional surface and represents a gap in the rock record

Half-life

• The half life of a substance can not be changed.

• Carbon 14 is used for recent dating (less than 50,000 years)

• 1 half life = 50%, 2 half lives = 25%, etc.

Air

• Warm air holds more moisture than cold air

• Warm air is less dense than cold air therefore it rises!

• As altitude increases, pressure decreases

Wind

• Winds are named for the direction from which it blows

• Winds always blows from high to low pressure

Weather

• The closer the air temp and dew point the greater the chance for precipitation

• A rising barometer = good weather, a falling barometer = poor weather

• Fronts occur where air masses meet• The greater the difference in

characteristics of air masses the greater the chance for severe storms

Weather con’t

• Precipitation occurs where air is forced to rise ex. Low pressure system, along a front, windward side of mountain, itcz

• Hi pressure = clockwise and out• Low pressure = counterclockwise and in• Marine climates have warmer winters and

cooler summers than continental climates• Weather in US usually moves west to east

(with slant to ne)

Weather con’t

• mP – moist and cold – northern oceans• cP – dry and cold –northern Canada• mT – moist and warm – warm oceans and

gulf of mexico• cT – warm and dry – deserts of sw USA• cA – very cold and very dry – extreme

northern Canada in winter only

Hurricanes

• Form over warm ocean waters, need moisture for energy

• June1-nov 1• Extreme low pressure system• As pressure decreases, wind increases• Danger from storm surges, flooding and

wind• evacuate

tornadoes

• Usually early spring but anytime• Mostly in mid-west but anywhere• Most likely when mT air from gulf collides

with cP air from Canada• Narrow path of destruction compared to

hurricanes

rotation

• Spin on axis• Earth rotates once every 24 hours• Rotation rate = 15 degrees per hour

revolution

• Movement around the Sun • 1 revolution = 356 ¼ days• Revolution rate = ~ 1 degree per day• Ellipitical orbit w/ sun at one foci• The closer we are to the sun the faster we

go.• Closest to sun in winter (jan 1) farther in

summer (july 1)

Polaris

• The altitude of polaris = your latitude• Look north to see polaris• All stars and constellations appear to

rotate counterclockwise around polaris

seasons

• Caused by– Tilt of earth on axis– Revolution around the sun– Parallelism

insolation

• Sun’s rays most intense at 90 degrees• Shadows are longer when sun is lower on

horizon• The higher the angle of insolation the

warmer the temps• In the US you look south to seen the sun

in the afternoon• Sunrises in east sets in west

atmosphere

• Earth receives shortwave energy from sun which becomes longwave when reflected by surface

• Greenhouse gases are carbon dioxide, methane and water vapor

moon

• The moon revolves around the earth in about 29 ½ days

• Seen by reflected sunlight• Solar eclipse at new moon, lunar eclipse

at full moon• Tides are highest and lowest at new and

full