Last updated on June 28th, 2023 at 09:59 pm
Write a short note on:
Sial and sima
- The uppermost thin layer of the earth’s surface is composed mainly of minerals like silica and alumina, thus it is called sial.
- The oceanic crust mainly consists of silica and magnesium it is therefore called sima.
- Explain the function of wind with example.
- The wind is an active agent of erosion and deposition in deserts. When the wind blows it lifts and transports sand from one place to another and when it stops blowing sand falls and gets deposited in low hill-like structures called sand dunes. sand dunes are mostly seen in Rajasthan.
- Explain the function of metamorphic rocks with example.
- Igneous and sedimentary rock can change into metamorphic rocks under great heat and pressure. For example, clay changes into slate and limestone into marble.
Additional question answer
Fill in the blanks:
- The radius of the earth is …………… kms [6371]
- Oceanic crust mainly consists of …………….and……………. [silica & magnesium]
- Mantle layer of earth extends up to a depth of ……….[ 2900 km.]
- What are fossils?
- The remains of dead plants and animals trapped in the layer of rocks are called fossils.
- What are igneous rocks?
- When the hot magma comes out of the volcano, it cools down and solidifies into a rock. this rock is called igneous rock.
- What is lava?
- The reddish molten magma which comes out from the interior of the earth is called lava.
- Which is the innermost layer of the earth and what is its radius?
- The innermost layer of the earth is the core and its radius is 3500 km.
- What is the main mineral constituent of the oceanic crust?
- The oceanic crust mainly consists of silica and magnesium also called SiMa.
