Rock and Minerals - Class 2 Notes & Olympiad Questions

Rocks

Rocks are a big part of our Earth. They make up almost everything around us, like hills, mountains, and valleys. We can find rocks under the ground, in the seas, and in rivers.

Rocks come in many different colours and types. Some rocks are shiny, some are hard, and some are soft. They have different uses depending on their hardness and type.

Examples of rocks are Granite, Marble, Sandstone etc.

Hard Rocks

1. Hard rocks include granite, sandstone, and marble.
2. Marble is used to make beautiful floors, statues, and furniture.
3. Granite is super strong and is great for making statues and floors. Some kitchens even have countertops made of granite.
4. Sandstone is another hard rock that is used for building things like temples and forts.
5. Examples of hard rocks are Granite, Basalt, Marble, Gneiss etc.

Soft Rocks

1. Coal and slate are examples of soft rocks.
2. Slate is a soft, grey-coloured rock. Some houses have roofs made of slate. We also use slate for blackboards and writing slates.
3. Coal is a soft rock that we use as fuel in steam engines, factories, and for cooking.
4. Examples of soft rocks are Sandstone, Shale, Limestone, Siltstone, Chalk, Mudstone etc.

Difference between hard rock and soft rock

Rock Cycle

The rock cycle is like a never-ending process, where they go through changes and transformations to become new rocks.

Types of Rocks

There are three types of rocks:

1. Igneous Rocks

a) These rocks are formed when hot, molten materials called magma or lava cool down and become solid.
b) Igneous rocks are born from the cooling of magma or lava from the earth’s core.

Examples: Granite, scoria, obsidian, and pumice.

2. Sedimentary Rocks

a) Sedimentary rocks are formed when small pieces of rocks, called sediments, get buried and pressed together over a long time.
b) Sedimentary rocks are made from these compressed and cemented sediments.

Examples: Sandstone, limestone, shale, gypsum, and conglomerate.

3. Metamorphic Rocks

a) Metamorphic rocks are formed when existing rocks are put under a lot of heat and pressure deep inside the Earth for a very long time.

Examples: marble, slate, quartzite, and gneiss.

Minerals

Minerals are like tiny ingredients that make up rocks. They come in different shapes, sizes, and colours.
These minerals have different purposes and are used to make many things we use in our daily lives.

Some of the minerals are:

Talc: This is a very soft mineral that is used to make talcum powder.

Silica: Silica is a mineral that can be found in sand. It is used to make glass, like the glass in windows or bottles.

China clay: China clay is also a soft mineral. It is used to make pottery, like beautiful plates and cups that we use for eating and drinking.

Diamond: Diamonds are the hardest minerals found in nature. They are used to make beautiful jewellery and cut glass.

Graphite: Graphite is a soft mineral that is used to make pencil lead.

Quartz: Quartz is a mineral that is used to make watch dials.