1. Topic 2: Measuring the Earth

2. Size and Shape Earth’s shape is not a perfect sphere
flat at the poles, bulging at the equator
It’s true shape is an OBLATE SPHEROID

4. Models A Model is a way of representing the properties of an object
A MODEL of the Earth is always shown as a PERFECT CIRCLE (globe)

5. How do we know the earth is round?
Photographs taken from space
As you watch a ship travel away from you, it appears to sink and not just fall off.

6. Outer Spheres of the Earth
Atmosphere- gas layer
Hydrosphere- water layer
Lithosphere- solid/rock layer

7. Which Layer is
Densest?

8. Spheres of the Earth
Open your E.S.R.T. to page 1

9. Atmosphere The Atmosphere or gas layer is made mostly of….
Nitrogen and oxygen
Page 14 of the E.S.R.T. shows the properties of the Atmosphere

10. Atmosphere These zones of the atmosphere are:
Troposphere
Stratosphere
Mesosphere
Thermosphere
In between each layer is a interface known as a PAUSE

12. Please answer
the questions
on Page 1 of
your Notes

13. 1. 4600°C, 1.2 million atmospheres (+/- 0.2)
Answers:
°C, 1.2 million atmospheres (+/- 0.2)
2. oxygen °C
4. 0°C km

14. Locating Positions on Earth’s Surface
How does GPS locate positions on earth?
Coordinate system- using 2 points to find a location
Page 2

15. Latitude and Longitude

17. Finding the coordinates
Always written as Latitude, Longitude
Every degree is separated into
60 minutes
Followed by a direction N, S, E, W
ESM is 40°50’ N, 72°49’W

18. To get to the next line of
Page 2 10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H
To get to the next line of
latitude, you must move
in which of two directions?
Latitude
Equator

19. 10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H
North
South

20. Latitude is measured
and
from the
North
South
Equator

21. To get to the next line of longitude, you must move 10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H
To get to the next line of
longitude, you must move
in which of two directions?
Prime Meridian

22. 10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H
West
East

23. Longitude is measured
and
from the
East
West
Prime Meridian

24. On the coordinate system, plot the coordinates given in your notes:10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H D A B C

25. State the coordinates for each of the letters in the figure above:10 20 30 40 50 60 70 80 90 15 45 75
105
120
135
150
165
180 E F G H
20°N, 75°E
65°N, 50°W
70°S, 15°E
10°S, 135°W

26. BASED ON THE ____________
Page 3
LATITUDE
ALTITUDE
BASED ON THE ____________
OF _______________
POLARIS

27. Latitude
Latitude is the angular measurement in the northern hemisphere from the equator to the north star (Polaris) is equal to latitude in the northern hemisphere

29. LATITUDE =
ALTITUDE

30. POLARIS CAN ONLY BE
SEEN IN THE
HEMISPHERE
NORTHERN

34. Polaris with Time Traces

35. So……..
If I find the angle of Polaris to be 27° from my location what is my latitude?
27° North
If I am in Manorville at 42°06’ N, 75°55’W. What is the altitude of Polaris?
42°

36. Polaris at Different Latitudes

37. 25°N, 100°W
Altitude of Polaris
25°

38. 30°S, 100°E
Altitude of Polaris
Can't be seen!

39. 80°S, 65°W
Altitude of Polaris
Can't be seen!

40. 45°N, 105°E
Altitude of Polaris
45°

41. LONGITUDE
BASED ON EARTH’S
ROTATION

42. LONGITUDE
EACH HOUR,
EARTH ROTATES
15°
(360°/24hrs)

43. HOW MANY TIME ZONES?

44. HOW MANY TIME ZONES?
24 TIME ZONES
15° APART

45. People on the
same line of
longitude have
the same
Local Time

46. Example: Two students record a difference in local time of two
hours. How many degrees of
longitude apart are they?
15° x 2 hours = 30°

47. 7pm THESE LONGITUDE LINES ARE 15° APART.
If it is 2pm in time zone A, what time is it in time zone B? B 7 A 6 5 4 3 2
7pm

48. If it is 9pm at location X, what time is it at location Y?

49. If it is 11am at location W, what time is it at location Z?

50. What’s the highest longitude?
Since a circle is 360o, Longitude increases East and West of the Prime Meridian from 0o at the Prime Meridian to 180o
At the 180o you can find the International date line