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

Question: How are sedimentary rocks formed? Name the different types of sedimentary rocks. Describe any one.

Answer: Sedimentary rocks are formed by repeated deposition of rocks particles that are worn away from mountains by winds and water.

The different types of sedimentary rocks are:

1. Conglomerate
2. Sandstone
3. Shale
4. Limestone

Shale:

1. It is made up of solidified clay apart in thin layers.
2. It is used in making bricks and cement.

Question: What are the different types of metamorphic rocks? Describe any two.

Answer: The different types of metamorphic rocks are:

1. Marble
2. Slate
3. Gneiss
4. Quartzite

Slate:

1. It is formed from shale a sedimentary rock.
2. Like shale, it splits into flat layers.
3. It is used in making brick and cement.

Gneiss:

1. It is formed from granite.
2. It has different kinds of minerals in it< giving it a striped or streaked look.
3. It is used as building stone.

Question: Describe the various uses of rocks and minerals.

Answer: Uses of rocks are:

1. Rocks are used as building material for making schools, houses, roads and bridges. Some rocks are used in their original form while some are used to make bricks, cement, tar and concrete. For eg: granite, limestone, sandstone and marble.
2. Rocks give us useful metals for eg meals like iron, copper and aluminium are used for making utensils and precious metals like gold, platinum are used for making jewellery.
3. Rocks give us fuel for eg: coal is used for producing electricity, heating and moving nuclear energy.
4. Rocks are used as gemstones for eg: diamond, ruby, sapphire and emerald are used for making jewellery because when they are polished they appear shiny and beautiful.

Uses of minerals:

1. Minerals like Sulphates and Nitrates are used as fertilizers because they help the plant to grow.
2. Minerals are a very important part of our diet. For eg: minerals like calcium, sodium and iron are required for the healthy functioning of our body.