Download Earth Science

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Astrobiology wikipedia, lookup

Timeline of astronomy wikipedia, lookup

Astronomical unit wikipedia, lookup

Rare Earth hypothesis wikipedia, lookup

Geocentric model wikipedia, lookup

Extraterrestrial life wikipedia, lookup

Comparative planetary science wikipedia, lookup

Dialogue Concerning the Two Chief World Systems wikipedia, lookup

Regents Earth Science
Topic II:
Measuring the Earth
Is the Earth Round?
• Not exactly………so Columbus wasn’t
• The Earth appears round but when
“measured”, it is actually flattened at the
poles and bulging at the equator…
….**making the Earth a slightly, slightly,
slightly, slightly Oblate Spheroid
This is not how
It looks!!!!
How can we tell that the shape of
Earth is nearly a sphere?
1. Photographs from space (#1)
2. Masts of ships appearing to “sink” as
they travel past the horizon
3. Gravity Measurements (more
gravitational pull at the poles—closer to
center of Earth = higher weight)
4. Observations of Polaris (the North Star)
Spheres of the Earth:
• Atmosphere: shell of gases that surround
the Earth.
– It is layered into zones. Each zone has a
specific temperature, and composition
• Hydrosphere: all bodies of water on Earth
(oceans, lakes, rivers, ground water)—
covers 70% of Earth’s surface
• Lithosphere: solid portion of the Earth
(rock and soil layer)
ESRT’s Cover
How do you locate Positions on
• Coordinate System: a grid of imaginary
lines that are used to locate a point on a
two-dimensional surface (a map)
• Latitude-Longitude System: the most
commonly used coordinate system used
for the Earth. This system is based on
observations of the sun and other stars.
Lines of Latitude (Parallels):
• Measures distance north or south of the
equator (0°
• 90° at Poles
• Parallel
Lines of Longitude (Meridians):
• Measures distances east or west of the
Prime Meridian (Prime Meridian is 0-180 is highest)
• Lines connect at the north and south poles
How do you determine Latitude?
• The angle that Polaris makes with the
horizon is equal to the person’s latitude
(Polaris never moves)
• Altitude = Latitude
Polaris Facts:
• Only seen in the Northern Hemisphere
(not south of the Equator)
• Points Due (exactly) North
• NOT the brightest star in the sky!
• Use Pointer Stars to Find
• Directly above North Pole
“Big Dipper”—easy to see
How do you determine Longitude?
• Find the time difference between your
local time and Greenwich Mean Time
(GMT) and then multiply by 15 (Greenwich
is at 0 Longitude)
– This works because the Earth rotates 15
every hour and the Time Zones are 15
longitude apart (24 total, 1 hour apart)
World Time Zones
• If your time is EARLIER than the time
given for GMT, then you are WEST of the
Prime Meridian
• If your time is LATER than the time given
for GMT, then you are EAST of the Prime
U.S. Time Zones
• Topographic Maps: shows the shape of
Earth’s surface by using contour lines
(the shape of the lines indicate the shape
of the land)
What are Contour Lines?
• lines of equal elevation (height above sea level)
**there are other lines on other types of maps as
well (Isotherms: equal temperature / Isobars:
equal pressure)
What to look for when looking at
Topographic Maps:
• Contour Interval: difference in height
between two adjacent contour lines
Index Contour: Bold lines
with elevation values
Contour Interval = 20 ft.
• Scale: distances on a map represent the
actual distance on the ground
• Map Direction: often indicated by some
type of arrow pointing north (if there is no
arrow, then north is the top of the map)
• Benchmark: a metal marker placed in the
ground that shows the exact elevation.
..on a topo map, BM X (Elevation)
• Gradient: rate at which a field changes
from place to place—also called slope or
Change in Field Value
Gradient =