Transcript Earth Science MCAS Review

Mrs. McCarthy’s
MCAS Review
Earth Science
7th Grade Curriculum
–Mapping the Earth
–Earth’s Structure
–Heat Transfer
–Earth’s History
–The Earth in the Solar System
Mapping the Earth
• Recognize, Interpret, & Create models of
Earth’s Features with Mapping.
Topographic
Maps show the
elevation of an
area of land using
contour lines.
Earth’s Structure
The Layers of the Earth
Crust- Solid, Oceanic &
Continental
Mantle- Largest Layer
with lithosphere &
asthenosphere;
convection currents
Outer Core- Liquid Molten
Metal
Inner Core- Dense; Solid;
Iron
Heat Transfer
• Heat moves in predictable ways
from warm objects to cooler
objects
• Heat Energy Moves in 3 ways:
• Conduction
• Convection
• Radiation
Conduction :occurs
when energy is
passed directly from
one item to another
Convection
Convection : movement of
gases or liquids from a
cooler spot to a warmer
spot.
Examples- Air Masses,
Earth’s Mantle; Ocean
Convection : movement of FLUIDS
(GAS OR LIQUID)
from a cooler spot to a
warmer spot.
WIND
EARTH
BOILING
Radiation :The sun's rays
travel in straight lines called heat
rays. When sunlight hits the
earth, its radiation is absorbed or
reflected.
Darker surfaces absorb more of the
radiation and lighter surfaces reflect the
radiation.
What are the 3 major
factors that effect a
region’s climate?
1. Latitude
• Locations closer to Earth’s equator will be
warmer
• Locations closer to Earth’s poles will be
cooler
2. Elevation
• Higher elevations such as
mountain peaks will be cooler than
low elevations such as valleys
3. Distance to Coast
• Coastal regions near Earth’s oceans will
be effected by water temperature and
ocean breezes
• Why?: Because water holds its
temperature longer than air and land
Example: Cape Cod is
usually warmer than the
rest of Massachusetts in
the winter and cooler in the
summer because it is
surrounded by ocean
water.
Earth’s History
Millions of years ago
all of Earth’s land
masses were
together in one large
super continent
called Pangaea.
Over time Pangaea
spread apart due to
continental drift and
sea-floor spreading.
Today, we have 7
continents on Earth.
Evidence
Evidence of the Continental Drift
Theory include:
•
•
•
•
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Physical Evidence (Puzzle-like Continents)
Fossil Evidence
Africa
Glacial Evidence
South
Climate Evidence
America
Plant Evidence
The Changing Surface
• In addition to plate tectonics, Earth’s
surface is ever changing due to:
–Earthquakes
–Volcanoes
–Weathering, Erosion & Deposition
• Earthquakes occur when Earth’s
plates shift and cause shaking on
the surface
• Most Earthquakes occur at Plate
Boundaries
• A Tsunami is a tidal wave in the
ocean caused by tectonic
(Earthquake) movement of
Earth’s plates.
Most volcanoes form at plate boundaries
• Diverging- mid ocean
ridge, rift valley
• Converging- island
arcs/ Mt. St. Helens
• Hot spots- not on a
boundary- Hawaii
Rock is broken into
smaller pieces by:
• Freezing & Thawing
• Release of Pressure
• Growth of Plants
• Action of Animals
• Water
• Abrasion
Earth in the Solar System
All objects are
affected by GRAVITY.
Gravity’s force is
stronger on larger
objects. Our solar
system is held
together by the Sun’s
gravity. The Sun’s
gravity keeps the
planets orbiting
around it.
Just as the planets orbit around the
sun due to the Sun’s strong gravity,
the moon orbit’s Earth due to
Earth’s Gravity.
The moon rotates on
its axis and revolves
around Earth at the
same rate, that’s why
only one side of the
moon is visible from
Earth.
Phases of the Moon
Lunar Phases
The Moon appears to go through a complete set of
phases as viewed from the Earth because of its motion
around the Earth, as illustrated in the following figure.
Lunar Eclipses
During a Lunar Eclipse, the Sun, Earth,
& Moon align so that the moon is not
reflecting any of the Sun’s light. The
moon is not visible from Earth at this
time.
Solar Eclipses
During a Solar Eclipse, the
Sun, Moon, & Earth align so
that the Sun’s light is not
reflecting on Earth. The Sun is
not visible from Earth at this
time.
Day & Night
• Earth rotates on its axis once every 24
hours (1 day).
• When Earth is turned toward the Sun, it is
daytime.
• When Earth is turned away from the sun, it
is nighttime.
Earth revolves around the sun once
every 365 ¼ days (1 year).
When the Northern Hemisphere is angled
toward the Sun (direct rays), it is summer.
When Northern Hemisphere is angled
away from the sun (indirect rays), it is
winter.
Summer in N.H.
Winter in S.H.
Winter in N.H.
Summer in S.H.
UNIVERSE
GALAXIES
SOLAR SYSTEMS
PLANET
• The Universe is made of billions of
Galaxies
• Galaxies are made of billions of Stars
• We live in the Milky Way Galaxy
• The Sun is the only Star in Our Solar
System
UNIVERSE
• We live on Planet Earth
GALAXIES
SOLAR SYSTEM
PLANET