The Four Realms of the Earth

Prepared by: Ms. Siddhi Hegde Pawar Public SchoolKandivali

How many planets do we have?

Which planet has life?

EarthLiving planet.

Only planet that supports life.

Life possible on Earth because-

Biosphere

Atmosphere

Hydrosphere

Lithosphere

Lithosphere• Derived from Greek word for stone –

litho.• Solid outer part of earth.• Thin cover of soil. Helps the plants to

grow.• 29% of earth’s surface.• 7 huge masses – 7 continents.• The edges of the continents and the

ocean floors together form the lithosphere.

Structure of the Earth• The earth’s

interior is based on density of materials and behaviour of seismic waves.

• The crust forms only 1 % of the volume of the earth, 84 % consists of mantle and 15 % makes up the core.

Crust• Outermost and thinnest layer.• Thickness varies.• Two types – continental crust and

oceanic crust.

SIMA

SIMA

Cross section of the Earth

• Rocks • Minerals

Types of rocks

Igneous

Intrusive

Extrusive

Sedimentary

Metamorphic

Atmosphere

• Derived from Greek word for air – atmo.

Vertical change in average global atmospheric temperature. Variations in the way temperature changes with height indicates the atmosphere is composed of a number of

different layers (labeled above). These variations are due to changes in the chemical and physical characteristics of the

atmosphere with altitude.

Most of our planet's weather occurs in the troposphere. This image shows a view of this layer from an airplane's window (Photo © 2004 Edward

Tsang).

Hydrosphere

• Derived from Greek word for water – hydro.

• The second factor controlling tides on the Earth's surface is the Sun's gravity. The height of the average solar tide is about 50% the average lunar tide. At certain times during the moon's revolution around the Earth, the direction of its gravitational attraction is aligned with the Sun's (Figure 8r-2). During these times the two tide producing bodies act together to create the highest and lowest tides of the year. These spring tides occur every 14-15 days during full and new moons.

Forces involved in the formation of a spring tide

• When the gravitational pull of the moon and Sun are at right angles to each other, the daily tidal variations on the Earth are at their least (Figure 8r-3). These events are called neap tides and they occur during the first and last quarter of the moon.

Forces involved in the formation of a neap tide.

The following illustration describes the flow pattern of the major subsurface ocean currents. Near surface warm currents are drawn in

red. Blue depicts the deep cold currents. Note how this system is continuously moving water from the surface to deep within the

oceans and back to the top of the ocean. (Source: Arctic Climate Impact Assessment -ACIA).

Hydrologic Cycle.

Biosphere

• Derived from .Greek word for life – Bio.