Science OGT Review
Content Standard: Earth and Space
Ø Explain how evidence from stars and other celestial objects provide
information about the processes that cause changes in the
composition and scale of the physical universe.
Ø Explain that many processes occur in patterns within the Earth’s
Ø Explain the 4.5 billion year history of Earth and the 4 billion year
history of life on Earth based on observable scientific evidence in
the geologic record.
Ø Describe the finite nature of Earth‘s resources and those human
activities that can conserve or deplete Earth’s resources.
Ø Explain the processes that move and shape Earth’s surface
Ø Summarize the historical development of scientific theories and
ideas, and describe emerging issues in the study of Earth and space
Ø There are four areas of study that contribute to Earth
The Big Bang Theory
Ø Explosion 13.7 billions
Ø Galaxies are moving
away from central
Ø Red-shift- the light most
galaxies gives off is close
to the red end of the
spectrum because energy
weakens as it is stretched
How is a star formed?
Ø Nebula- dust and gas get pulled together
by gravity in space.
Ø Extreme heat is produced, causing
nuclear fusion, which causes hydrogen
protons to join together producing the
massive energy just as our sun does.
Ø The nebula depending on the size,
becomes a massive star or a low mass
The Lifecycle of Stars
The Life Cycle of a Star
Ø Main sequence stars convert hydrogen to
helium in their cores. When the star runs
out of hydrogen, the helium can be
changed into heavier elements. The cores
of the stars shrink and their surfaces
expand and become cooler.
Ø Large group of stars; billions in the
Ø Our solar system- sun, Earth and 8 other
planets belong to the Milky Way Galaxy.
Spiral, Elliptical & Irregular
Ø Does the sun revolve around the earth, or does
the earth revolve around the sun?
Ø What causes all the planets, sun and the moon
to not come crashing down on us?
Law of Universal Gravitation
Ø The planets revolve around the
sun due to gravity!
Ø Newton proposed between any
two objects there is attraction
that is proportional to the
masses of the objects and the
distances between them.
Ø In English: the more mass an
object has, the stronger gravity
pulls on the object with less
mass than itself.
Ø For example, Earth has more
mass than our moon, this is
why the moon revolves around
The Reason We Have Night & Day
Ø The earth rotates on its axis
which brings different parts of
the earth in contact with the
sun at certain times.
Ø The reason the sun appears to
“rise in the east” is because
that’s the way our earth
rotates, bringing the eastern
part of the U.S. in contact with
the sun first.
Ø FYI- 1 day is 1 rotation of the
Earth. 1 year is 1revolution of
the Earth around the sun.
Tools Used By Astronomers
Ø Answer the following questions
Ø 1. Name 4 areas of study that contribute to Earth
Ø What does red-shifting mean?
Ø How is a star formed?
Ø What is the core of the sun made of?
Ø Name 3 types of galaxies?
Ø What type of galaxy is Earth from?
Ø How many planets are recognized?
Ø Does the sun revolve around the earth or does the moon
revolve around the earth?
Ø What causes night and day on earth?
Ø What are tools used by an astronomer?
Ø Earth is tilted as it
revolves around the
sun which allows
various places to
have a certain
weather during the
Ø 4 Seasons
During winter for Cleveland and other places in the
Northern Hemisphere, we are tilted out of contact with
these hottest rays from the sun. This is why it is cold.
Places along the equator are hot year round because they
are in direct contact with the sun’s hottest rays or very
close to them
When the Northern Hemisphere is having winter, the
Southern Hemisphere is having summer. This is
because the Earth’s tilt brings the S. Hemishere in
contact with the hottest direct rays.
Places along the equator are warm year round because the
hot direct rays never move far from the equator.
Places close to the N. & S. Pole never get the sun’s direct
hot rays. This is why its never warm in these areas.
Ø Occurs when the
moon either partially
or completely blocks
the sun from the
Ø The last total eclipse
was the solar eclipse
of July 11, 2010. The
next will be the solar
eclipse of November
Plate Tectonics Theory
Ø Theory that the Earth’s crust is made up of many plates
that are floating on top of the Earth’s mantle layer that is
molten liquid rock. These plates interact with each other
in many ways…
Ø 1) When plates slide past each other creating friction,
Ø 2) When Earth’s plates collide and push up they can
create mountain ranges
Ø 3) Magma from mantle can erupt passed space between
2 plates or melt through a soft crustal plate.
Ø 4) The crustal plates sit on the mantle layer of the Earth.
The mantle is liquid hot rock that convection currents.
These convection currents push the plates around
causing continents to drift and seafloors to spread.
Plates & Boundaries
The Continental Drift Theory
Ø Alfred Wagener proposed that
at one time all continents
joined together in a single
Ø Evidence to support theory is
Ø 1) identical fossils of an
animal were found on
Ø 2) identical rock layers were
found on many continents
Ø 3) continents fit together like a
Ø Rock sediments get laid down where the oldest
rock is at the bottom.
Ø Which layer is the youngest?
Ø Due to plates moving, sometimes layers of the
earth get folded or faulted.
Ø Fossil layers are a source of fossil fuels
Ø Organisms turned into carbon which we use as
fuel, including gasoline, oil and coal.
Ø Nonrenewable Resources- cannot be ever
replaced or renewed; took millions of years to
Ø Renewable Resources- can be renewed and
replaced. Sunlight, water power, wind, wood,
crops are all renewable
Ø Sunlight never runs out!
Ø Crops and wood can be grown constantly
What is a downside to fossil fuels?
Ø They will run out one day soon
Ø They cause Global Warming
Ø Global warming is the planet becoming warmer
throughout the years.
Ø Greenhouse Effect- The Earth has an insulation
layer of CO2 in its atmosphere that helps keep
warmth from the sun. The layer is thin enough to
let some heat escape so our planet does not get
Ø When fossil fuels & wood are burned they give
off carbon dioxide (CO2) which causes the
insulation layer to be too thick so not too much
heat is trapped not being allowed to escape.
This causes Global Warming!
What Can We Do?
Ø We can use clean alternative energy sources
(non carbon dioxide producing sources)
Ø We can conserve resources
Ø Car pool
Ø Riding a bicycle instead of driving
Ø Use public transportation
Ø Turn off water and electricity when not in use
Ø Idea of protecting our resources and
Ø Natural places that must be protected can
be grouped into different biomes.
Ø Biomes are places that have distinct
climate (how much rainfall they receive
and their temperatures) and types of
plants and animals that thrive in these
Type of Biome Climate
Desert Little rain & large daily change in temperature (hot
in day & cold at night)
Rainforest Lots of rain with hot temperatures
Tundra Has dry & wet seasons, but very cold
Grasslands Has dry & wet season. Temperature is hot.
Deciduous Forest Moisture evenly distributed throughout the year.
Has warm summers and cold winters.
Coniferous Forest Moisture varies throughout the year. Has cool
summers and cold winters.
Biomes of the World
Ø Conditions in our atmosphere such as
temperature, sunshine, rain, snow and clouds.
Ø Sun is main cause for weather
Ø Certain materials heat up differently. Darker
objects absorb heat from the sun better than
light ones, which reflect heat better. This is why
asphalt parking lots can be so hot in summer.
Ø Different surfaces heat differently, causing hot
air to rise and cooler air to sink. When this
happens wind occurs.
Ø Amount of precipitation and the temperature an
area gets throughout the year.
Ø Cleveland’s weather for today may be warm and
sunny and tomorrow it could be cold & rainy.
Ø Cleveland’s climate however is warm summers,
cold winters and moisture throughout the year.
Ø Why is this so??
Ø The distance around Earth's orbit
is 584 million miles Earth travels in
its orbit at 66,700 miles an hour,
or 18.5 miles a second.
Ø Layers of the Earth
Ø Atmosphere: 78% Nitrogen, 21%
Ø Sediment Rocks erode, wear
Ø Metamorphic Rock- inside earth
Ø There are many cycles on and
within Earth. A few of the most
important are (1) atmospheric
circulation, (2) ocean currents, (3)
the global heat conveyor, (4) the
hydrologic cycle, and (5) the rock
The Rock Cycle
The Water Cycle