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Unit 2: The Earth in Space
Mr. Ross Brown
Brooklyn School for Law and
Technology
Aim: How is our Earth composed?
• Date: 16 Sept 2016
Do now: This question may require the use of
the Earth Science Reference Tables.
The Earth's shape most closely resembles which of
the following object:
a)
b)
c)
d)
a basketball
a pear
a ping-pong ball
an apple
And another, just for fun!
This question may require the use of the Earth
Science Reference Tables.
According to the Earth Science Reference Tables,
the equatorial radius of the Earth is
approximately:
a)
b)
c)
d)
637 km
6370 km
63700 km
637000 km
The Earth in Space
Taken December 7, 1972, by the crew of the Apollo 17 spacecraft, at a distance
of about 45,000 kilometers (28,000 miles). (source: Wikipedia)
In this unit we will learn:
• The characteristics of Earth’s 3 major zones
• How seismic waves provide insight into Earth’s
interior
• What the magnetosphere is
• How the Earth’s gravitational pull is created
What are Earth’s Interior layers?
• 19 Sept 2016
• Do now: Compare the mass of the crust to the
mass of the mantle to the mass of the core.
Use fractions or percentages. For example, the
crust represents _____% of the mass of the
earth, the mantle is _____%, and the core is
______%.
What are Earth’s Interior layers?
• Can’t see inside Earth, but scientists have
“seen” with seismic waves, vibrations
– Caused by earthquakes or explosions
• Earth has layers, or zones
– Crust: thin, solid, outermost layer
– 1% of earth’s mass
• Mass: the amount of matter in an object
– Oceanic Crust: 5km-10km thick
– Continental Crust: 15km-80km thick
What are Earth’s Interior layers?
– Mantle:
•
•
•
•
•
2/3 of the earth’s mass
2,900km thick
Upper mantle is cool and brittle (lithosphere)
Due to heat and pressure, next layer of rock flows
Asthenosphere exhibits plasticity (solid that can flow)
– Core
• Center of the earth, composed mostly of iron
• Outer core is dense liquid layer
• Inner core is very dense and solid
Earth’s Interior layers
Inferred Properties of Earth’s
Interior
Aim: How do we draw inferences
about the composition of the
earth?
• 20 Sept 2016
• Do now: This question may require the use of
the Earth Science Reference Tables.
The true shape of the Earth is best described as a:
a)
b)
c)
d)
perfect sphere
perfect ellipse
slightly oblate sphere
highly eccentric ellipse
Aim: How do we draw inferences
about the composition of the
earth?
This question may require the use of the Earth
Science Reference Tables.
At which location would an observer find the
greatest force due to the Earth's gravity?
a) North Pole
b) New York State
c) Tropic of Cancer (23.5N)
d) Equator
Seismic Wave Studies
• Two types of seismic waves
– P waves (primary) travel through liquids, solids,
and gases. Faster than S waves.
– S waves (secondary) travel only through solids.
– Core blocks seismic waves in shadow zones
How does Gravity affect objects on
the Earth?
• Gravity: the force of attraction that exists
between all matter in the universe
Newton’s Law of Gravitation
• The force of attraction between any two
objects depends on their masses and the
distance between them.
• Mass is the amount of matter in an object.
• Weight is an object’s mass and distance from
center of the earth.
• Newton’s Universal Law of Gravitation states
that any two bodies in the universe attract
each other with a force that is directly
proportional to the product of their masses
and inversely proportional to the square of
the distance between them.
How does the earth move in
space?
• 22 Sept 2016 (my sister’s birthday)
• Do now: This question may require the use of
the Earth Science Reference Tables.
The length of an Earth day is determined by the time
required for approximately one:
a)
b)
c)
d)
Earth rotation
Earth revolution
Sun rotation
Sun revolution
How does the earth move in
space?
• 22 Sept 2016 (my sister’s birthday)
• Do now: The autumnal equinox occurs today
at 10:21 AM. What does this mean? Why does
this happen?
How does the earth move in
space?
• Rotation: spinning on an axis. Each rotation is
about 24 hours (one day)
• Revolution: each revolution takes about 365
days (one year)
How does the earth move in
space?
• Earth’s revolution around the sun is slightly
elliptical, not quite a circle.
• Closest to the sun at perihelion, farthest from
the sun at aphelion.
How does the earth move in
space?
• Earth’s orbit lies in a plane but earth’s axis is
23.5° from perpendicular to the plane.
• As earth revolves around the sun, this tilt
produces our seasons.
How does the earth move in
space?
• Solstice: the Sun stops, or the days stop
lengthening or shortening
• Equinox: equal length of day and night
Thought Question
• What causes our winter in the Northern
Hemisphere?
How do we keep track of time on
our earth?
23 Sept 2016
•
Do now: Base your answers to questions 15 and 16 on the United
States time zone map shown below. The dashed lines represent
meridians (lines of longitude).
15) If the time in Buffalo, New York, is 5 a.m., what time would it be in San
Francisco, California?
a) 8 a.m.
b) 2 a.m.
c) 3 a.m.
d) 4 a.m.
How do we keep track of time on
our earth?
23 Sept 2016
•
Do now: Base your answers to questions 15 and 16 on the United
States time zone map shown below. The dashed lines represent
meridians (lines of longitude).
16) The basis for the time difference between adjoining time zones is Earth’s
a) 1° per hour rate of revolution
b) 1° per hour rate of rotation
c) 15° per hour rate of revolution
d) 15° per hour rate of rotation
How do we keep track of time on
our earth?
• The earth is (roughly) a sphere
• Circumference=360°
• Every 15° is an hour, 24 hours in a day
– How many time zones are there around the
world?
• International Date Line is where the next day
begins
World Time Zones
How does the US account for
regional time differences?
• Daylight Saving Time
– Goal is more sunlight hours for more work in the
summer
How do we keep track of activity
across the earth?
• Satellites: Any objects in orbit around other
body with a larger mass.
• Uses: meteorology, communications,
navigation, science, military, government
• Orbits: geosynchronous, polar
Satellite Images
How can we keep track of our
location on the Earth?
• 26 Sept 2016
• Do now: This question may require the use of the Earth
Science Reference Tables.
How are latitude and longitude lines drawn on a globe of
Earth?
a)
b)
c)
d)
Latitude lines are parallel and longitude lines meet at the poles.
Latitude lines are parallel and longitude lines meet at the
equator.
Longitude lines are parallel and latitude lines meet at the poles.
Longitude lines are parallel and latitude lines meet at the
equator.
How can we keep track of our
location on the Earth?
• Earth is a sphere
• Rotates on an axis, which runs through the
geographic poles
• Split by an equator (separates north & south
hemispheres (half-spheres))
How can we keep track of our
location on the Earth?
• Parallels tell us how far north and south of
poles we are
• Distance north or south is latitude, measured
in degrees. Equator is zero, poles are 90°
– Brooklyn is about 40.5°N
How can we keep track of our
location on the Earth?
• East and west are measured in meridians
– Half-circles running from pole to pole
• Longitude is distance of meridian, in degrees
– Brooklyn is about 74°W
How do maps represent actual
features of the earth?
• 27 Sept 2016
• Do now: This question may require the use of the Earth
Science Reference Tables.
An airplane takes off from a location at 17°S latitude and flies
to a new location 55° due north of its starting point. What
latitude has the plane reached?
a)
b)
c)
d)
28°N
38°N
55°N
72°N
• This question may require the use of the Earth Science Reference
Tables. Base your answer to this question on the topographic map
below. Points X, Y, and Z are locations on the map. Elevations are
expressed in meters. Which profile best represents the topography
along the dashed line from point X to point Y?
How do maps represent actual
features of the earth?
• Cylindrical Projection: most common, often
referred to as Mercator Projection.
• Accurate near equator, but distorted closer to
poles.
How do maps represent actual
features of the earth?
• Conic Projection: imagine a cone lined with
mirror placed over the earth
• Accurate in middle of cone, rather badly
distorted as we move out.
How do maps represent actual
features of the earth?
• Interrupted Projection: In order to focus on
landmasses, and to flatten the spherical
shape, omits large spaces, such as oceans.
How can we fully use the information in the
Earth Science Reference Tables?
• 28 Sept 2016
• Do now: Please write your name on your copy of the ESRT. Take
these first few moments and leaf through your copy.
• Become familiar with the different sections and how each relates to
the various parts of our earth science curriculum.
What protects the Earth from solar
radiation?
• 14 October 2015
• Do now: What causes the Aurora Borealis?
What is the Magnetosphere?
NO!
What is the Magnetosphere?
• The region in space around our Earth where
charged particles are controlled by the
planet’s magnetic field
• Protects us from solar radiation