In this lesson students review the actions of weathering and examine how erosion acts on landscapes. They explore the types and causes of erosion. Students identify and discuss actions that exacerbate erosion and how human activity may affect erosion of landscapes and landforms.
Review the terms ‘weathering’ and ‘erosion’ from Lesson 2. If needed, re-view the video Weathering and erosion to remind students of the concepts weathering and erosion.
Inform students that just as there are different types of weathering, there are a variety of forms of erosion that act in different ways on soil, rocks and landscapes.
Discuss common causes of erosion such as wind and water. Explain how these causes can result in dramatic consequences for beaches and coastal areas in particular due to the rough winds and seas.
Show students images of eroded areas to explain the types of erosion. Images could include:
Small scale water erosion.
Large scale water erosion.
- Simulate erosion by using sand and water to demonstrate how water can affect coastal landforms. Inform students that erosion can be of varying degrees and be carried out over short and long periods of time.
- Show students images from the previous lesson and explain how some erosion can be acute, like that caused by storms (eg coastal erosion) or chronic, like that caused by rivers moving over landscapes (eg the Grand Canyon)
Teacher note: See Background information (PDF, 432 KB) and the section entitled Lesson 3: Erosion investigation to assist you in conducting an investigation into the effects of water on landscapes.
- Inform students that in order to understand the effects of water on landscapes they will plan and conduct an erosion investigation using sandcastles.
- Inform students that they will have instructions to follow to complete the investigation considering fair testing.
- Distribute the worksheet Investigation planner (Word, 389 KB). Read through the sheet to show students how to conduct the investigation and enter their data.
- Gather equipment and move students to outside area to conduct the investigation.
- Conduct the investigation as per the investigation instructions.
- Gather students together to discuss the investigation. Ask students to identify actions that affected the sandcastles during the investigation and to think about how their findings might relate to large-scale erosion of beaches and other landforms.
Watch the video The changing face of Australia, 1970: Uluru
Ask students to identify and list actions that might exacerbate erosion.
Identify how human activity might affect soil, rocks and landscapes. Use the images of erosion to assist in their identification; such as overuse of recreational vehicles, excessive farming or land clearing. Inform students that during the following lesson, they will conduct a field study on erosion in the school grounds. They will identify areas of erosion and the underlying causes, where possible.