Weathering | AQA GCSE 9-1 Geography

What are the different types of weathering? What is freeze-thaw weathering? What is carbonation?

This is the thirty-sixth video for the AQA GCSE 9-1 Geography course, and the third video of the Physical Landscapes topic.

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Video Script:
Weathering is the weakening and break down of rocks in their original place.

There are three main types: physical weathering, chemical weathering and biological weathering.

An example of physical weathering is freeze-thaw. Water enters cracks in the rock, and later freezes when temperatures drop. As it freezes, it expands, which widens the crack. The ice then melts, allowing water to go deeper into the crack. This process repeats over time, causing the rock to break apart.
Another example is salt weathering. Seawater contains salt, which means when it evaporates it leaves salt crystals behind. These crystals grow, which exerts pressure on the rock and over time can cause the rocks to break away.

Chemical weathering is caused by chemical changes, and can be seen with a process known as carbonation. Rainwater absorbs carbon dioxide in the atmosphere, making it slightly acidic. This means the rainwater reacts with alkaline rocks such as limestone and chalk, slowly causing them to dissolve.

Biological weathering is carried out by plants and animals. Plant roots are a good example of this - roots can grow into small cracks in the rock, and as they grow larger the cracks do the same. Over time this can cause small pieces of rock to break away.

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GCSE Geography
07/05/2023
Keducate

Видео Weathering | AQA GCSE 9-1 Geography канала Keducate