Rock
Contents
Key Stage 1
Meaning
Rock is a hard, stiff and firm material. The objects known as 'rocks' are made out of the material rock.
About Rock
Rock is used to make buildings because it is very hard and strong. There are many different kinds of rock. Some are shiny, others are dull. Some are smooth and other are rough, but they are all hard, stiff and firm. They cannot be bent or stretched.
Key Stage 2
Meaning
Rock is a hard, stiff and firm material made of crystals or grains.
About Rock
- Rock is made from grains which are tiny pieces of rock that are stuck together.
- Some rocks have crystals inside them which are grains that have sharp edges. You can often see crystals because they are shiny and sparkle like glitter.
- The shape of grains in the rock depends on how it was formed.
- The size of crystals also depends on how the rock formed.
- Rock formed at the bottom of a lake or the sea has rounded grains inside.
- Rock formed near volcanoes has lots of crystals.
Examples
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| This limestone has lots of rounded grains and was formed at the bottom of the ocean. | This mudstone formed at the bottom a lake and has rounded grains. | Sandstone is made of rounded grains of sand stuck together. |
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| This basalt has lost of very small crystals inside it and formed form a volcano. | Granite formed from magma stuck underground near a volcano and has crystals inside it. | Quartz is a very large crystals rock formed near volcanoes. |