1. UNIT 1 PLANET EARTH The Earth ‘s place in the Solar system
The Earth’s movements and consequences
Finding places on the Earth
Time zones on the Earth
Maps :representations of the Earth
The scale of a map

2. The Earth’s place in the Solar system
The Earth is an almost perfect sphere .It is slightly flattened at the North Pole and the South Pole.
Its surface area is 510 million km
30% is land - continents and islands
70% is covered by water-ocean, seas, lakes and rivers.

3. The Earth has its place in the solar system
It is the third planet from the sun
Mercury, Venus, Earth, Mars, Jupiter, Uranus and Neptune (Pluto is no longer considered to be a planet)
The solar system is comprised of the following celestial bodies:
Stars
Planets
Satelites
Our Solar system is located in a spiral galaxy called the Milky Way.
The Universe is made up of more than a hundred billion galaxies (spherical, elliptical, spiral and irregular)

6. The solar system is comprised of the following celestial bodies:
A star, called the sun, which produces its own light
Planets, which rotate on their own axis
Satelites, which are smaller than planets and rotate on their own axis.They revolve around some planets.
Our Solar system is located in a spiral galaxy called the Milky Way.
The Universe is made up of more than a hundred billion galaxies (spherical, elliptical, spiral and irregular)
 A galaxy is made up of planets,stars,gas clouds and cosmic dust.

7. Spherical Galaxy

8. Spiral Galaxy

9. Irregular Galaxy

10. Elliptical Galaxy

11. The Milky Way The solar system is part of the Milky Way

12. Why is life possible on Earth?
Life exists on Earth because of three main factors:
The distance from the Sun.
This creates an appropriate temperature which is not too hot or too cold.
(Venus 457ºc,Uranus -220ºc)
The presence of water.
Water supports life and is necessary for survival.
The existence of an atmosphere
There is a layer of gases surrounding the Earth which protects life from dangerous solar radiation.

13. The Earth and its movements
The Earth is not a perfect sphere.It is slightly flattened at the poles
Its is said to have a geoid shape.
The Earth has two hemispheres
The Northern hemisphere and the Southern hemisphere

15. How does the Earth move?
The Earth moves in two different ways; rotation and revolution
ROTATION:
This is the movement of the earth as it turns on its own axis once every 24 hours.It moves in a counter clockwise way.That is from west to east
This gives us day and night.

17. REVOLUTION:
This is the movement of the earth around the Sun , creating an elongated or elliptical orbit.Our planet orbits the sun at an average speed of km/h It is the force of gravity that keeps us in orbit
It takes the Earth 365 days and 6 hours to complete one revolution This movement gives us the seasons
The earth’s axis is tilted and so the sun’s rays hit the earth differently depending on the time of year. This causes variation in the length of time in days and temperature. As a result we get the seasons: spring , summer, autumn and winter.
The seasons in the Northern and Southern hemisphere are opposite.

18. Video links: https://www.youtube.com/watch?v=UdvIep63cXk

19. How can we locate an exact spot on the Earth’s Surface?
We can do this by using imaginary lines which are called geographic coordinates
The coordinate are known as lines of longitude and latitude and are expressed in degrees ,minutes and seconds.
Latitude is the angular distance between any point on the earth and the equator. (0º-90º)
Longitude is the angular distance between any point on the Earth
and prime meridian (Greenwich meridian)(0º-180º)
These lines can also be called meridians and parallels.
Meridians are imaginary lines of longitude that go from north to soouth
Parallels are imaginary lines around the earth and which are parallel to the Equator

20. Parallels
The equator is an imaginary circle around the widest part of the Earth.it divides our planet into two equal halves or hemispheres
The equator is 0º latitude .after that there are 90 parallels to the north and another 90 parallels to the south.
Important parallels are:
Tropic of Cancer
Arctic circle
Tropic of Capricorn
Antartic Circle

21. Meridians Meridians are imaginary semi-circles
that go from pole to pole.
The prime meridian or Greenwich
meridian is 0º longitude.It is named
after the British observatory at Greenwich
because the prime meridian runs through
it.
There are 180 meridians to the east and
another 180 to the west.

23. Time zones
The way the Earth rotates means that the Sun rises first in the countries in the east .
The Earth is divided into 24 time zones
This corresponds to the 24 hours that it takes the Earth to make a completerotation on its axis.
The 360ºof the Earth’s sphere are divided up by the 24 hours and this gives us 15 degrees
Each time zone is 15 degrees and corresponds to 1 hour

24. World time zones

25. How do we represent the Earth ?
We use maps to represent the Earth’s sphere on a flat Surface
Map projection makes this posible
A map is the true representation of the whole or part of an área on a flat surface.
a projection is the result of projecting a 3D image onto a flat surface.
There arethree main types of map projection
Cylindrical,conical and planar

26. Cylindrical projection
This is made by wrapping a cylinder around a globe and projecting the details onto the Surface to make a world map

27. Conical projection
In a conical projecton,the globe is projected onto a cone .When it is opened up it is shaped like a fan.it is used to Project mid latitudes
On the flat Surface the meridians are converted into straight lines and the paralles take the shape of arcs of concentric circles

28. Planar projection
Here the globe is projected onto a flat suface.The result is acircular projection
The globe only touches the flat Surface at the pole which is being mapped.
It is best for polar regions

29. Maps There are many types of maps Topographic maps.
These represent in detail the relief,cities,towns or villages,roads and railways
Thematic maps:
Show specific aspects of an área.For example,they can
Be political,relief,climate or population

30. The scale of maps and plans
Maps and plans represent large área on small Surface so we need to know the relation between size and the size shown on the map.
Numeric scale:
Expresed using a fraction in which the numerator is the unit of size on the map and the demoninatorshows the equivalent units in real life
1: cm represents centimetres in real size
Graphic scale:
This indicates the distance on a map using a straight line divided into equal parts ,like a ruler