Download - Unit 2 Planet Earth
UNIT 2:PLANET EARTH
HOW EARTH MOVES
The Earth moves in two ways: rotation and traslation.
Rotation: Movement of the Earth around its own axis. It causes night and day. The Sun rises in the east and sets in the west.
Revolution: The Earth orbits the Sun. This causes the seasons.
Rotation
Revolution
THE SEASONS
The Sun heats the northern hemisphere or the southern hemisphere more strongly depending on the time of year.
Perihelion: Earth is closest to the Sun. Aphelion: Earth is farthest from the Sun. The days when seasons change are called
equinox and soltice. Spring equinox, Summer solstice,
Autumn equinox, Winter solstice.
The seasons
ACTIVITIES
1. Where the Sun rise? Where does it set? Why do you think we see it that way?
2. True or False?a) The days when the season changes are called
ellipse and ecliptic.b) Spring equinox is on 21st June.c) In the northern hemisphere days are longer
than nights during winter.
THE MOON
The Moon is the Earth’s only satellite. Its surface is full of craters. Caused by the
impact of meteorites. The Moon has two movements:
Rotation: It takes 28 days. Revolution: It orbits the Earth. It takes 28 days.
We always see the same side of the Moon because rotation and revolution take the same time. The other side is called the hidden side.
PHASES OF THE MOON The Moon shows 4 different phases:
New Moon: We cannot see the Moon. First Quarter: We can see the right side
illuminated. Full Moon: We see the whole Moon illuminated. Last Quarter: We can see the left side
illuminated.
Moon Phases
ECLIPSES
An eclipse occurs when a celestial body hides another temporarily. It can be partially or completely.
Lunar eclipse: It occurs when Earth blocks the Sun's rays from the Moon.
Solar eclipse: It occurs at New Moon when the Moon passes between Earth and Sun.
Lunar eclipse
THE TIDES
The tides are periodic movements of the level of the seas due to the attraction of the Moon and the Sun.
When the water level rises is called high tide.
When the water level goes down is called low tide.
ACTIVITIES
1. What do we call the side of the Moon we cannot see?
2. Which has more influence on tides, the Moon or the Sun?
3. Define:a) Eclipseb) Tidec) Season
4. True or false?a) The Earth takes 375 days to orbit the Sunb) The Earth rotates from east to west.c) The Earth goes around the Sun in an elliptical orbit.d) The revolution of the Earth is the movement of the
Earth around its own axis.
THE EARTH’S SPHERES
The Earth is formed by four spheres: The atmosphere: It is formed by a mixture of
gases, called air. The hydrosphere: is all water on the Earth. The geosphere: is the solid part altough it can
be viscous. Three layers: crust, mantle and the core.
The biosphere: is the living things which inhabit the Earth.
ACTIVITIES
1. Make a drawing of the Earth’s spheres and label them in English and Spanish.