Page 118 - Active Science 5 Ebook and Activity

Activity 10.1

Fix a candle in a plate and light it. After sometime, the wax will start trickling down and will
become solid on cooling. This will show you how the igneous rock is formed.

Sedimentary Rocks

As a river flows down the mountains, it washes off sand, mud, clay and pebbles down
the hill slopes. These reach the river banks and are deposited in layers. These are then
cemented together by minerals and wind for over thousands of years to form sedimentary

rocks. Sedimentary rocks are always formed in layers. Sometimes, the shells of dead
animals add to the rocks, giving amazing colours and patterns.

Some common examples of sedimentary rocks:

1. Sandstone: Sandstone is a soft rock made from grains of sand. Sand particles are

stuck firmly together. Red sandstone and yellow sandstone are commonly used in
buildings.

Do You Know?
The Red Fort and
Qutab Minar in

Delhi are made of red
sandstone.
Taj fort

2. Limestone: It is a sedimentary rock
consisting of the mineral calcium and
tiny animal shells. It is formed from

the accumulation of shell, coral, algal
and fecal debris. It is used to make
lime, cement, paint, etc. Limestone

3. Conglomerate: It is a rock made up
of uneven texture with coarse grains

formed by cementing together of pebbles
and gravel. It is used in construction
and is also polished to make ornaments.
Conglomerate
4. Shale: It is made of layers of clay like,

fine-grained sediments. It is used in Activity 10.2
making bricks and cement. It is also Take a piece of shale. Put it in a bowl of water.
used in surfacing roads. After sometime, it will smell like wet mud.

118 Active Science-5