Inside Our Earth

Crust, Mantle, and Core.

The uppermost layer over the earth's surface. It is the thinnest of all the layers. It is about 35 km on the continental masses and only 5 km on the ocean floors.

Silica and Alumina on the continental masses. Hence called 'sial' (si-silica + al-alumina).

Silica and Magnesium. Hence called 'sima' (si-silica + ma-magnesium).

Just beneath the crust is the mantle which extends up to a depth of 2900 km below the crust.

The innermost layer with a radius of about 3500 km. It is made up of Nickel and Iron ('nife'). The central core has very high temperature and pressure.

Any natural mass of mineral matter that makes up the earth's crust. Rocks can be of different colour, size, and texture.

1. Igneous rocks (fire). 2. Sedimentary rocks (settle down). 3. Metamorphic rocks (change of form).

When molten magma cools, it becomes solid. These are called igneous rocks or primary rocks.

Extrusive: Magma comes on surface (lava), cools rapidly, fine-grained structure (e.g., Basalt). Intrusive: Magma cools deep inside the crust, cools slowly, large grains (e.g., Granite).

Rocks roll down, crack, and hit each other and break into small fragments (sediments). These sediments are transported by wind/water and compressed/hardened to form layers of rocks (e.g., Sandstone).

The remains of dead plants and animals trapped in the layers of rocks.

Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure (e.g., Clay to Slate, Limestone to Marble).

The process of transformation of the rock from one to another under certain conditions in a cyclic manner.

Hard rocks are used for making roads, houses, and buildings. Stones are used in games. Minerals are obtained from rocks.

Naturally occurring substances which have certain physical properties and definite chemical composition. Used as fuel (Coal, Petroleum) and in industries (Iron, Aluminium).

In South Africa, it is about 4 km deep. To reach the centre of the earth, one would have to dig 6000 km deep (impossible).

Latin word Ignis meaning fire.

Latin word Sedimentum meaning settle down.

Greek word Metamorphose meaning change of form.

The Earth is a dynamic planet.

Radius of Earth is 6371 km.

Deepest mine is in South Africa.

Crust is only 1% of earth's volume.

Mantle is 84% of earth's volume.

Core is 15% of earth's volume.

Continental crust contains Silica and Alumina (Sial).

Oceanic crust contains Silica and Magnesium (Sima).

Core contains Nickel and Iron (Nife).

Temperature rises with depth inside earth.

Igneous rocks are primary rocks.

Basalt is extrusive igneous rock.

Granite is intrusive igneous rock.

Deccan plateau is made of basalt.

Grinding stones are made of granite.

Sandstone is made from grains of sand.

Sedimentary rocks contain fossils.

Clay changes into Slate (Metamorphic).

Limestone changes into Marble (Metamorphic).

Red Fort is made of Red Sandstone.

Taj Mahal is made of White Marble.

Rock cycle creates and destroys rocks.

Magma turns into Igneous.

Igneous turns into Sediments.

Sediments turn into Sedimentary.

Sedimentary turns into Metamorphic.

Metamorphic melts into Magma.

Coal is a fossil fuel.

Petroleum is a fossil fuel.

Natural gas is a fossil fuel.

Minerals are natural resources.

Gold is a precious mineral.

Uranium is found in earth.

Rocks have different textures.

Rocks have different hardness.

Diamond is the hardest mineral.

Talc is the softest mineral.

Sedimentum means settle down.

Metamorphose means change form.

Ignis means fire.

Geology is the study of earth.

Petrology is the study of rocks.

Fossils help date rocks.

Earthquake waves help study interior.

Crust is broken into plates.

Interior is not liquid (mostly solid/plastic, outer core liquid).

Magnetic field generated by Core.

We live on the Crust.

Geological time scale concepts used