Latitude-Longitude System –

most commonly used coordinate system for the Earth, based on observations of the sun and other stars

Latitude - point’s position measured as an angle north or south of the equator. 0° is Equator and 90° is the poles* lines of latitude known as

parallels

Longitude – distance east or west of the prime meridian from 0° to 180°

* lines of longitude known as

meridians

In what direction does the sun rise and in what direction does the sun set?

Rises in the East and sets in the West

So if you are looking down at the Earth (at the North Pole) from space, in what direction does the Earth rotate (clockwise or counterclockwise)?

From West to East or Counterclockwise when looking down on the North Pole

Rotation Rate = 15°/hour

How many times does 15° go into 360°?

Takes one day or 24 hours to rotate 360°

We Can determine time anywhere else in the world by knowing the longitude and time where you are.

- 0° Longitude equals Prime Meridian = Greenwich Mean Time

- 15° one way or another from the Prime Meridian = 1 hour ahead or behind

- We are about 75° West Longitude

- Greenwich Mean Time (GMT) is also known as Zulu Time

Solar Noon – the time when the sun is highest in the sky at any given location

Clock Time – based on the time at 0° Longitude and the distance in degrees longitude from the Prime Meridian for any given location on Earth

- Clock Noon does not always represent solar noon, quite close- Noon sun is never directly overhead for all locations on Earth- In NYS the sun is always in the Southern Half of the Sky

• Guatemala City, Guatemala 14° 37’N 90° 31’W• Kingston, Jamaica 17° 59’N 76° 49’W• Manila, Philippines 14° 35’N 120° 57’E• Tananarive, Madagascar 18° 50’S 47° 33’E• Singapore, Singapore 1° 14’N 103° 55’E

What time is it at these locations around the world if it is 9AM here?

Which of these cities is located on the same line of longitude as we are?

Why is it warmer there year round?

Actual Shape of Earth = OBLATE SPHEROID

- Flattened at the poles and bulging at the equator

• Equatorial Circumference = 40,076 km

• Polar Circumference = 40,008 km

• Equatorial Diameter = 12,757 km

• Polar Diameter = 12,714 km

Plane of Horizon – apparent line that separates Earth from sky in all visible directions

Celestial Object – something in the sky or space

Celestial Altitude – altitude of an object in the sky above the horizon measures as an angle

Celestial Sphere – imaginary sphere covering an observer

Zenith – point directly above observer on celestial sphere

***When viewed from space or scaled down to a model, the Earth appears to be a perfect sphere, since the bulge is almost negligible

Evidence of Earth’s Nearly Spherical Shape

• Ships and Eclipses

•Photographs Taken From Space

•Observations of the Altitude of Polaris

Evidence of Earth’s Oblate Spheroid Shape

• Changing ground distances between lines of latitude

• Weight (gravity) difference at equator and poles

= changes in elevation

ex. Mountain, valleys, hills, canyons

Compared to the diameter of the Earth, even the highest mountain is quite small, thus relative to the overall size of the Earth it is actually quite smooth

Erotasthenes Info

Earth’s “Spheres”

• Lithosphere

• Hydrosphere

• Atmosphere

Lithosphere• Continuous outer solid rock layer of Earth

• CRUST/ Part of the Mantle

• More dense than hydrosphere, thus below

• Varies in thickness from 70 to 150 km

• Oxygen and silicon most common elements (see ESRT)

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Hydrosphere• Thin layer of water that covers majority of Earth’s surface

• Approx. 71% of surface covered with water

• 3.5 to 4 km thick, thin compared to other spheres

• All bodies of water

• Hydrogen and oxygen most abundant

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Atmosphere• Shell of gases surrounding Earth

• Separated into layers each having distinct characteristics

• Several hundred km thick

• Least dense of three spheres

• See ESRT

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Field – region of space with a measurable quantity at every point

Ex. Gravity, temp., pressure, elevation

Isolines – lines that connect points of equal field value

Types of Isolines

• Contour - elevation

• Isobar - pressure• Isotherm - temperature

Scalar Field – a field that has magnitude only, no direction

Ex. Elevation, temperature, pressure

Vector Field – a field that shows values for magnitude and direction

Ex. Wind, magnetic fields

The picture to the right is an example of a field map. In this example, the numbers on the map represent the concentration of gasoline found at that location. So the map simply shows how much of something (in this case gasoline) is found at many locations.

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The image on the left is an example of a gasoline field map with the 40 isoline drawn in.

Notice that the line connects points that all have the same value. In this example, the circle connects all of the points with a value of 40. That means that every point on that line has a value of exactly 40

This map has all of the isolines drawn in, at an interval of 10 (each line is 10 units apart) is shown to the right:

D.O.Q 10/11/12

Sunrise = 7:13 AM

Sunset = 6:27 PM

Hours of Daylight =

Moon Phase = Waning Crescent, 19%

Do Now: • Copy down daily observations

• Be prepared for a quiz

Questions:

1.