Do now!

Can you read through the rocks brain-map ?

Last lesson

• Three main rock types

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

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

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

Identifying some rocks

Mr Porter gave you some unnamed rock samples which you tried to classify as igneous, sedimentary or metamorphic.

Today’s lesson

• Weathering of rocks – Freeze-thaw weathering

Carefully read this paragraph

In high mountainous areas, rain water can seep into the small cracks in a rock. At night-time the air gets very cold and the water freezes. When water freezes it expands making the crack wider. During the day the water melts and falls deeper into the now larger crack. This happens repeatedly, the crack gets bigger and bigger, and eventually a piece of rock is broken away from the mountain.

Educational freedom fighters!

This class is being held hostage by educational freedom fighters (just outside). We have to decide as a class which is the most important word in the paragraph. If we get it wrong, they are going to shoot us!!!!!

Homework – Due Tues 9th March

• Draw diagrams to show how freeze thaw weathering happens. No words!