Weathering

Lesson Aims ALL – to know what weathering is MOST – to know what mechanical, chemical and biological weathering is SOME – to know different ways that mechanical, chemical and biological weathering occurs

Today’s key terms: Weathering Mechanical weathering Chemical weathering Biological weathering Freeze-thaw weathering Exfoliation Solution Scree Pores

Watch the slide show Watch the slide show of images and information to do with weathering. Take notes in your books It does not have to be full sentences it can bullet points

Weathering is the break down of rocks in their original place (the rocks do not move they get worn away from where the are)

It is largely caused by elements of the weather such as rainfall and changes in temperature

Mechanical weathering is also known as physical weathering

Mechanical weathering breaks up rocks without any chemical changes Mechanical weathering breaks up rocks without any chemical changes. It often results in piles of angular rocks called scree at the base of the rock feature.

Chemical weathering is a chemical reaction between the rock and acidic rainwater

Biological weathering involves the actions of flora and fauna Biological weathering involves the actions of flora and fauna. Plant roots are effective at growing and expanding in cracks in rocks

Mechanical weathering – Freeze Thaw Wider world page 234 Take notes on what freeze-thaw weathering is Then copy this diagram

Mechanical weathering – Exfoliation Wider world page 234 Take notes on what exfoliation is

Chemical weathering – Solution Wider world page 234 Take notes on what chemical weathering is Then copy this diagram

Quiz Weathering is the breakdown of rocks where they are carried away. True or False? What type of weathering is freeze-thaw? Name a type of chemical weathering What type of weathering involves plants breaking down rocks? What is the name for angular rocks? What is mechanical weathering also known as? Chemical weathering is a reaction between the rock and what else? Chemical weathering reacts strongly with which two rocks?

Answers False Mechanical Solution Biological Scree Physical weathering Acidic rainwater Limestone and chalk

Homework Choose one rock type to research – metamorphic, igneous, sedimentary Create an A3 poster on your rock type. Include the following: Position on geological timescale How it was created linking with the rock cycle Features of the rock type Examples of rock Images / diagrams Example of a place in the UK with that rock type How it might be affected by weathering How that rock type may be used for example in concrete of for building

Lesson Aims ALL – to know what weathering is MOST – to know what mechanical, chemical and biological weathering is SOME – to know different ways that mechanical, chemical and biological weathering occurs