What Is Erosion?

Erosion is the process of gradual destruction or wearing away by wind, water or other natural sources. Headland erosion Do Now Look at the two images below and complete your 5W’s sheet

Learning Objectives . To know the location of Old Harry’s Rocks . To understand how they were made . To be able to link the features to the processes occuring Location Old Harry’s Rocks are in Swanage. This is in Dorset on Peveril Point near Bournemout h Task Describe the location of Old Harry’s Rocks

• Scale – How big the place is or how far away it is from other places • Continent – Which of the 7 continents is it on? • Country – What country is it in? • Compass points – Where in the country is it? What’s to the north, east, south or west of it? • Longitude • Latitude – These will tell us exactly where it is in the world • Evidence from the map that might help – is there a major river, desert, major city, an ocean or sea, or something else you’ve read from the map

Use your atlases to help https://www.youtube.com/watc h?v=ymjqCHEqZf8 cliff Crack

Solution Attrition

Hydraulic Corrosion action crack Cave

Blow holes cave arch Arch pillar stack Stack Stump

Coastal retreat How are Headlands and Bays Make aformed? copy of this diagram Sea

Soft less resistant rock (lots of Discordant Coastline erosion). E.g. chalk, sand, clay.

Hard more resistant rock (little erosion. E.g. limestone and chalk Wave Direction

Draw theWave above diagramConcordant andCoastline explain how it is formed.Direction Headlan d

Discordant Coastline Bay

Headlan d

Bay

Headlan d

Bay

Concordant Coastline Task Describe and explain how Old Harry’s rocks were formed using images Ext - For a named hard rock coast, explain the development of its coastal landforms. (6)

What is the What What diagram example that landforms could we we have could we draw? looked at? explain? Plenary cliff attrition hydraulic stump action • Draw a 3x3 box in the erosion sand solution arch back of your book and include some weathering abrasion stack cave of these words! crack weathering erosion Old Harry coast chalk wave wind

water ice gravity temperat ure physical chemical - - How Can We Stop Erosion?

Beach erosion is unavoidable.

We currently use a range of prevention methods to try to prevent the erosion occurring. Current Methods

Current prevention methods include:

Sand Dunes Vegetation Seawalls Sandbags Sand Fences Sand Dunes

Natural sand dunes are a widely known way of preventing erosion. They are formed naturally as the wind blows the sand across the beach and a build-up is created around an object that blocked the wind. Vegetation

Roots from the vegetation stretch down into the sand to help make dunes sturdier and hold the sand in place. They also help break the fall of rain drops or wave splash, easing the erosion from above, and help catch windblown sand. Seawalls

Seawalls are usually made from concrete, steel or boulders. They need to be strong to stand up to harsh waves and are most commonly used where buildings are in danger of erosion. They run parallel to the beach and are only temporary and expensive to maintain. Sandbags

Sandbags are usually made from burlap. They are filled with sand and act like a seawall but they are cheaper and easier to maintain.

‘‘Crews Install Sandbags on N.C. 12’’ by NCDOTcommunications is licensed under CC BY 2.0. Sand Fence

Sand fences are a simple, man-made method of erosion prevention. The spaces between the slats of the fence cause the wind to drop the sand particles they are carrying. This makes it a fast way to create sand dunes. Your Task

Are these methods the best methods around? Can you change them to make them more effective? You are going to create a structure to prevent erosion on a beach.

You will need to create a beach in your container and construct a structure using the provided materials to prevent your beach eroding.

Using the planning sheet, design your structure. What You Need

• Plastic container • A water bottle • Water • Access to objects students may • Blue food colouring wish to use to create their barrier • Sand (coarse and fine) • Planning sheet • Sticks • Stopwatch or timer Procedure

1. Pour the coarse sand up one side of your container.

2. Pour the fine sand over the top of the coarse sand.

3. Carefully, add water to the deep side of the container.

4. Add three drops of blue food colouring to the water. Procedure

Using your design, create your structure and add it to the beach scene to protect your coast.

Place your water bottle into the water and push down to create waves; create consistent waves to crash against your structure.

After two minutes, record the damage caused.

After five minutes, record the damage caused. Go Further

You have a house that you love. Unfortunately, the sea is slowly breaking away the wall in-between your house and the water’s edge. The erosion is happening all the way down the street and many houses are soon in danger of being swept into the water.

Your job is to attempt to sell the device you have created to the other homeowners. You want them to install your creation all the way down so that you can protect your house and theirs. Think about how you will sell them your idea and why they should choose your plan over the others’ in your class. Reflection

Did your structure stand up against the waves?

How did it cope after two minutes?

Was it still standing after five minutes?

What could you improve next time? Glossary

Burlap – A coarse canvas, used mainly as sacks. Coarse – A rough and harsh texture. Erosion – The wearing away of the land or material due to natural causes. Parallel – Line of structures that have the same distance between them the whole way along. Sand Fences – A wooden fence constructed along a shoreline to help construct sand dunes to assist in erosion prevention. Sand Dunes – Ridges of sand created as wind moves the sand grains to a location (found in deserts or near oceans and lakes). Seawalls – A wall constructed to prevent the sea water eroding the land. Structure – An object constructed from materials. Vegetation – A collection of plants, found in one location.