02 types of weathering

Freeze-ThawHeating & Cooling

Explain these terms.

Other Types of Weathering

Learning Objectives:

• To be able to explain how ‘Chemical weathering’, ‘Biological weathering’ and ‘Erosion’ occur.

• To compare about chemical weathering such as acid rain

• And biological weathering and its effects on rocks.

8G Weathering

Rock does not last forever. Look at the picture here – how can you tell that the rock has been damaged by the environment?

What might have done this damage?

What is the best rock for making a statue that will last for years?

• A selection of rocks • React with drops of

sulphuric acid or hydrochloric acid

• Record your observation.

• Draw a conclusion of what happens to some rocks when they react with acid.

Practical Activity

Safety First: Wear safety

goggles Stand up Tuck your chair &

bags under your desk

Tie back long hair

What is chemical weathering?

Rainwater is naturally acidic because carbon dioxide in the air reacts with rainwater to form carbonic acid.

This type of acid rain is weakly acidic and reacts slowly with minerals in rock.

The burning of fossil fuels produces oxides of sulphur and nitrogen which make rainwater more acidic.

This type of acid rain reacts quickly with minerals and weather rock more rapidly.

Slow chemical weathering

Slow and rapid chemical weathering

Rapid chemical weathering

Examples of chemical weatheringHow has chemical weathering affected these rocks?

8G Break it, move it, shape it!

Rocks may last a long time but they do change.

Even the toughest rocks can be broken down to smaller particles. We call this process weathering.

Small particles may be moved around to new areas. We call this transportation.

The two processes together (weathering and transportation) are called erosion.

Erosion and weathering…

EROSION is when rocks are gradually worn down.

WEATHERING is when rocks are broken up into smaller ones.

The ultimate result of both of these processes is SOIL.

What is biological weathering?

Examples of biological weatheringHow has biological weathering caused these cracks to form?

Explain how the rocks are broken down using the diagrams:

Other Types of Weathering

Learning Objectives:

• To be able to explain how ‘Chemical weathering’, ‘Biological weathering’ and ‘Erosion’ occur.

• To compare about chemical weathering such as acid rain

• And biological weathering and its effects on rocks.