End of Year – Science Study Guide

Earth Systems and Structures

Earth Systems

• Weather – daily temperature and precipitation

• Climate – average temperature and precipitation over time

Weather Tools

• Thermometer – used to tell the temperature• Barometer – used to tell the amount of air

pressure• Rain Gauge – collects the amount of rainfall that

has fallen• Hygrometer – tells how much moisture is in the

air (humidity)• Anemometer – indicates wind speed• Wind Vane – indicates wind direction

Types of Clouds

Cirrus• Wispy clouds that are the

highest clouds in the atmosphere; made of ice crystals

• Change in weather is coming

Stratus• These clouds form in layers,

blanket the sky, and bring gray/dull weather (fog) but they don’t bring rain

Types of Clouds

Cumulus• Large white puffy

clouds that may bring light rain

Cumulonimbus• Large dark clouds

that bring severe storms. Can expect heavy rains.

Air Pressure

Low Pressure (lousy)• Air rises and forms water droplets• Strong winds and dropping temperatures• Usually results in rain and storms

High Pressure (happy)• Several days of clear, sunny skies• Causes air to sink• Mild winds and stable temperatures

Air Masses and Fronts

• Air Mass – a large body of air with about the same temperature and humidity throughout

• Polar Air Mass – Cold air• Tropical Air Mass – Warm air

• Front – the boundary where two different air masses meet

Front Symbols

Types of Fronts

Warm Front• Laid back – rises over the cold front• Rain showers• Warmer air follows the front

Cold Front• Rude – takes over and pushes warm front up• Stormy/Windy weather• Cooler air follows the front

Types of Fronts

Stationary Front• Cold and warm front meet and neither moves• Overcast and rainy weather

Occluded Front• Two cold air masses meet and the warm air

between them is pushed upward.• Rain and Snow• Cool Temperatures

Types of StormsType of Storm Where it Forms Time of Year

Thunderstorm Within large cumulonimbus clouds

Spring or Summer

Tornado Cumulonimbus Clouds Spring or Summer

Hurricane Over warm ocean water Late Summer and early Autumn/Fall

Weather Patterns

Local Weather Patterns:• Moderate temperature and moderate rainfall

with hot Summers and cold Winters

• Thunderstorms, Tornadoes, and Hurricanes possible between Spring and Fall

What Affects Weather Patterns?

• Equator – an imaginary line that divides the Earth into the Northern and Southern Hemispheres

• Latitude – distance north or south of the equator

Climate Zones

Tropical Zones• Located closest to equator so it gets most energy from the sun;

warm and hot all year

Polar Zones• Located farthest from the equator near North and South Poles;

get least amount of energy from sun; cool and cold all year

Temperate Zones• Between Polar and Tropical Zones; amount of energy from the

sun changes throughout the year; seasons with very different temperatures

Two HemispheresNorthern Hemisphere Southern Hemisphere

Located above the equator Located below the equator

Opposite weather of Southern Hemisphere

Opposite weather of Northern Hemisphere

In Temperate Zone: In Temperate Zone:

Summer is June, July, August Summer is Dec., Jan., Feb.

Winter is Dec., Jan., Feb. Winter is June, July, August

Fall here Spring there

Spring here Fall there

Also Affecting Weather Patterns

Mountains • higher places have cooler temperatures than low places • Warm air moving toward mountains will rise and cool

(causing rainfall)Bodies of Water• tend to have milder weather• In Winter – warmer ocean water keeps nearby land

warm• In Summer – cooler ocean water keeps nearby land cool

Currents

• Current – a flow of air or water in a certain direction

• Two Types:• Global wind currents – in the air (includes Jet

Streams)• Ocean Currents – in the water (includes Gulf

Stream, El Nino, La Nina)

Global Winds

• Polar Easterlies – Travel from the Poles (east to west)

• Westerlies - Between the Poles and Tropics (travel west to east); where we live

• Trade Winds- Travel toward the Equator (east to west)

• The paths of global winds curve because…Earth spins on its axis.

Jet Stream

• An air current in the upper atmosphere that flows from East to West.

• Dip, bend and change position to affect North America’s weather

• Affect the paths of storms.

• From the North (dips South) – Polar Jet Stream lets cold air from Canada flow down into the US

• From the South (bends North) – Subtropical Jet Stream lets warm air flow in from the South

Ocean Currents

• Warm Currents (Tropical) – ocean currents that flow away from the equator; carry warm water near coastlines to cooler areas

• Cold Currents (Polar) – ocean currents that flow away from the poles; bring cooler temperatures to hotter coastlines

Ocean Currents

• The Gulf Stream – a warm ocean current in the Atlantic Ocean that moves warm waters toward the north. Helps keep weather mild during cooler months by warming the air and land.

• El Nino – unusual warming of surface temperatures in the Pacific Ocean, drought in Western US, Flooding in S. America

• La Nina – unusual cooling of the surface temperatures in the Pacific Ocean, flooding in Western US, drought in S. America