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. 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. 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

Quiz1. Weathering is the breakdown of rocks where they are

carried away. True or False?2. What type of weathering is freeze-thaw?3. Name a type of chemical weathering4. What type of weathering involves plants breaking

down rocks?5. What is the name for angular rocks?6. What is mechanical weathering also known as?7. Chemical weathering is a reaction between the rock

and what else?8. Chemical weathering reacts strongly with which two

rocks?

Answers

1. False2. Mechanical3. Solution4. Biological5. Scree6. Physical weathering7. Acidic rainwater8. 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