Today’s lesson

• Three main rock types

Three main rock types

Igneous

Three main rock types

Sedimentary

Three main rock types

Metamorphic

Igneous rocks

From the latin “ignis” meaning fire

Igneous rocks

Formed by the cooling of lava or magma

What’s the difference?

Igneous rocks

Made from crystals

Igneous rocks

Quick cooling forms small crystals, slow cooling forms large crystals

Igneous rocks

Basalt is formed by quickly cooling lava

Igneous rocks

Pumice is formed from lava that contains a lot of gas. It can float!

Igneous rocks

Obsidian is like dark glass formed when molten silica cools quickly!

Igneous rocks

Granite is made from magma that cools slowly underground

Sedimentary rocks

Sedimentary rocks

Sediments like sand and mud build up at the bottom of oceans and rivers

Sedimentary rocks

Over millions of years pressure from successive layers forms these into sedimentary rocks

Sedimentary rocks

Layers!

Sedimentary rocks

Animals and plants can be trapped in the sediments and can form fossils

Sedimentary rocks

Sandstone is made from sand grains stuck together

Sedimentary rocks

Limestone is made from the mineral calcite which came from the beds of evaporated seas and lakes and from sea animal shells.

Sedimentary rocks

Conglomerate rocks are made up of large sediments like pebbles. The sediment is cemented together with dissolved minerals.

Sedimentary rocks

Shale are formed from clay and mud that is compacted together by pressure.

Metamorphic rocks

Metamorphic rocks

Metamorphic rocks are rocks that have "morphed" into another kind of rock.

Metamorphic rocks

These rocks were once igneous or sedimentary rocks. The rocks are under tons of pressure, which causes heat build up, and this causes them to change.

Metamorphic rocks

These often also contain thin layers and crystals but are much harder than sedimentary rocks

Metamorphic rocks

Marble is limestone that has been metamorphised

Metamorphic rocks

Slate is metamorphised shale

Metamorphic rocks

Anthracite coal

Brain-map

Mr Porter is now going to put these slides on a loop so you can brain map them!