earth
DESCRIPTION
for elementary.. :)TRANSCRIPT
The Changing Earth
THE EARTH’S SURFACE
• The Earth is a planet that is almost spherical in shape and is made up of LAND, WATER, AND AIR.• Large masses of land, called CONTINENTS,
comprise about one-fourth of its surface.• 75% of it is covered with water.• The blanket of air surrounding Earth is
called ATMOSPHERE.
LAYERS OF THE EARTH
The outermost layer of the Earth is the CRUST.
Made up of loose solid rocks where continents and oceans are located.
The thickness of the continents and oceans varies from 10-65 km.
crust
2ND LAYER OF THE EARTH• MANTLE which is 2,880 km
thick.
• It is composed of solid rocks in the upper portion while, very hot molten rocks in its lower portion.
• The boundary between crust and mantle was discovered by ANDRIZA MOHOROVICIC.
• The boundary named as the MOHOROVICIC DISCONTINUITY or MOHO, varies from place to place.
3RD LAYER OF THE EARTH
• The CORE is divided into two parts:
• OUTER CORE and INNER CORE.
• Outer core is about 2880-4960 km thick.
• It is composed of molten iron and nickel. Studies of earthquake waves suggest that the outer core is made up of liquid(molten metals).
INNER CORE INNER CORE is believed
to be made up of solid materials.
It has a diameter of about 2560-2880 km.
The entire core has an approximate temperature of 4700°C.
SEISMOGRAPH An instrument that
measures the forces and direction of earthquake waves.
The density of the layers was suggested by the study of earthquake waves.
The center of the Earth is known to be very hot because of the magma released from volcanoes.
SCIENCE IDEAS• The layers of the Earth are the CRUST, the MANTLE, and the
CORE.
• The CRUST is the outermost layer of the Earth.
• The MANTLE, which lies beneath the crust, is composed of solid rock and hot molten rock.
• The CORE, is made up of molten iron, nickel in its outer portion and solid materials in its inner structure.
• The layers of the solid Earth is being studied using modern instruments like the SEISMOGRAPH.