NCERT 5th Class (CBSE) Science: Rocks and Minerals

Question: Name the three layers of the earth.

Answer: The three layers of the earth are:

1. Crust
2. Mantle
3. Core – Outer core, Inner core

Question: Name the three types of rocks with one example each.

Answer: The three types of rocks are:

1. Igneous rock – pumice
2. Sedimentary rock – shale
3. Metamorphic rock – marble

Question: What are metamorphic rocks ? How are they formed?

Answer: Rocks that have changed their form over time are called metamorphic rocks. They are formed due to physical and chemical changes in igneous, sedimentary, or older metamorphic rocks themselves due to heat and pressure.

Question: What are minerals ? Give any three examples of minerals.

Answer: All rocks are made up of substances called minerals. Minerals arwe chemics;l substances that occur in nature. Eg: gold, silver and iron.

Question: What are magnets? Mention the two types of magnets with examples.

Answer: Magnets are the substances that can attract objects made up of iron, cobalt and nickel. There are two types of magnets :-

1. Natural magnets: These are found in nature and these are made up of a mineral called magnetite.
2. Man-made: These are made by man from iron, cobalt and nickel.

Question: Name the different types of igneous rocks. Describe any two.

Answer: The different types of igneous rocks are:

1. Granite
2. Obsidian
3. Pumice

Obsidian:

1. It is smooth and glassy and is formed by quick cooling of lava.
2. It is used in making jewellery and ornaments.
3. It is usually black or dark coloured.

Pumice:

1. It is porous, or full of holes is formed from lava that is frothy with a lot of air within it.
2. It is the only rock that can float.
3. It is used in making light weight materials like concrete blocks.