1. Unit 2: Earth Science
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2. What is Earth Science?
Earth science is the study of the earth’s land, water, and air (outer space too!).
4 fields of earth science
Geology—study of the earth’s land, including the surface of the earth and the inside of the earth; how the earth changes; history of the earth.
Oceanography—study of the earth’s oceans, including what they contain and how they interact with the air.
Meteorology—study of the earth’s air, including weather.
Astronomy –the study of outer space, including planets, stars, and other objects in space.

3. Importance of Earth Science
You probable use earth science in some way every day.
Riding a car or bus.
Fuel is made from soil that geologists found underground.
Have you heard tomorrow’s forecast?
A meteorologist made this forecast.
Meteorologists study climate patterns.
They can predict systems of weather (i.e. El Ninos).
You can use your own knowledge of earth science to make smart decisions.
Planting a garden.
Buying a house.

4. Chapter 9: Describing the Earth
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5. Describing the Earth From space the earth looks like a gigantic ball.
Most of what you would see would be oceans.
One side of the earth appears dark and one side appears light.

6. Lesson 1: The Earth’s Features
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7. The Earth’s Features
People used to think the earth was flat!!!
The earth is actually shaped like a ball.
The earth is not perfectly round.

8. The Earth’s Surface
The earth’s surface includes areas of land and water.
The land area makes up about 30 percent of the earth’s surface.
The land on the earth’s surface is divided into seven major areas called continents.
North America
South America
Europe
Africa
Asia
Australia

9. The earth’s ocean is usually divided into four major bodies of water:
The major areas of water connect with each other and form one huge, continuous ocean.
The earth’s ocean is usually divided into four major bodies of water:
Pacific
Atlantic
Indian
Artic
You cannot see across an ocean to the land on the other side (curvature of the earth).
There are smaller bodies of water too: bays, gulfs, and seas.

10. Lesson 2: The Earth’s Rotation and Time
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11. The Earth’s Rotation
What determines when you go to school, eat lunch, or get ready for bed?
The time of day depends on the earth’s rotation.
Think about when you spin a top.
At first it stands upright and spins round and round
After a while, friction slows the top down.
It begins to wobble and eventually stops spinning.
Like a top the earth spins around.
But the earth never stops spinning.
The spinning of the earth is called rotation

12. The Earth’s Rotation
The earth spins (rotates) from west to east around an imaginary line that passes through the center of the earth.
The line is called the axis of the earth.
The axis passes through two points called poles.
The North Pole is the point farthest to the north of the earth.
The South Pole is the point farthest to the south of the earth.

13. Day and Night
The earth takes one day (24 hours) to rotate once on its axis.
The sun can only shine on one side of the earth at a time.
This is why one half of the day is light and one half of the day is nighttime.
Additionally, this is why the time of day is continually changing.
The time of time depends on where the sun appears in the sky.
The sun does not move across the sky, rather the earth’s rotation makes it appear as if the sun is moving.
As the sun turns from west to east, the sun appears to rise in the east in the morning.
Then it appears to move across the sky throughout the day and set in the west at night.

14. Standard Time Zones Time varies around the earth.
When it is noon at one point on the earth, it is midnight at one point that is halfway around the earth.
The remaining hours of the day are equally spread around the earth between noon and midnight.
All 24 hours in the day are occurring somewhere on the earth right now.
The earth has been divided into 24 standard time zones (one for each hour of the day).
A standard time zone is an area of the earth that has the same clock time.

15. Standard Time Zones
The boundaries of time zones do not follow exactly follow straight lines.
Over land areas, the zones usually follow borders of countries, states, counties, and towns.
The international dateline (imaginary line) marks the start of each day.
When you cross it going west, you move to the next calendar day.
When you cross it going east, you move to the previous calendar day.
How many time zones are in North America?

16. Standard Time Zones

17. Lesson 3: The Earth’s Movement in Space
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18. Revolution and Rotation
The movement of the earth in its orbit around the sun is the earth’s revolution.
A single revolution of the earth takes about 365 day (1 year).
While the earth is revolving around the sun it is also rotating on its axis.

19. Seasons
As the earth revolves around the sun, the earth’s axis always stays tilted at a 23.5 degree angle.
The tilt causes sunlight to fall more directly on different parts of the earth throughout its orbit.
This is what causes seasons.
When it’s summer in the Northern Hemisphere, that hemisphere is tilted toward the sun.
When it’s winter in the Northern Hemisphere, that hemisphere is tilted away from the sun.
When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere.
July is a summer month in the U.S. but it is a winter month in Argentina.

20. Seasons
No matter where you live the sun’s rays hot the earth more directly in the summer than in the winter.
The more direct the sunlight the more it heats up the ground.
Thus it is warmer in the summer than in the winter.

21. Lesson 4: Latitude and Longitude
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22. Lines of Latitude
Lines of latitude are imaginary lines that run in an east-west direction around the earth.
Latitude describes the distance north or south of the equator.
The equator is the line of latitude halfway between the North and South Poles.
Lines of latitude are called parallels.
The parallels are numbered in degrees.
Degrees are used to measure angles in circles and spheres.
A complete circle has 360 degrees.
Latitude numbers began at 0 at the equator and increase to 90 at each pole.
All latitude numbers north of the equator are followed by the letter N.
All latitude numbers south of the equator are followed by the letter S.

23. Latitude

24. Estimating Latitude Most maps do not show every parallel.
The person using the map must estimate the parallels not shown.
Use the following steps to do so:
Find the two parallels on other side of the desired location.
In your mind or on the paper fill in the missing latitude lines.
Use the lines/numbers you added to estimate the latitude of the location you are identifying.

25. Lines of Longitude
Lines of longitude are imaginary lines that run in a north-south direction from pole to pole.
Longitude lines are called meridians.
Longitude describes the distance east or west of the prime meridian.
The prime meridian is line of 0 degrees longitude (passes through Greenwich, England).
Meridians are numbered in degrees.
Numbering begins with zero degrees at the prime meridian and goes up to to 180 degrees.
The 180 degree line is on the opposite side of the earth from the prime meridian.
Numbers east of the prime meridian are followed by the letter E.
Numbers west of the prime meridian are followed by the letter W.
Estimating meridians can be done the same way as estimating parallels.

26. Locating Points by Latitude and Longitude
To locate any point on the surface of the earth you need to know both the latitude and the longitude of that point.
When stating any point’s location, the latitude is written before the longitude.

27. Hemispheres
The equator is the line of latitude halfway between the North and South Poles.
This line divides the earth into two hemispheres.
A hemisphere is half of the earth.
Two equal-sized hemispheres make up the whole earth.
The half of the earth north of the equator is called the Northern hemisphere.
The half of the earth south of the equator is called the Southern Hemisphere.