what processes cause beaches and spits to form in bays ?

What processes cause beaches and spits to form in bays?

Homework: due next lesson.

Explain the process of longshore drift. You may use a diagram to help with your answer (4)

Homework: from last lesson.

What happened at Holbeck Hall?

Why?

Peer assess another person’s work. Underline geographically specific vocabulary. How many words did they use?

Sizeable portrait

Coasts are a dynamic environment subject to constant shaping and reshaping by the actions of the waves.

In this lesson you will study the features created from material eroded by waves and consider their importance.

The lesson will continue preparation for the Swanage field visit.

Coming up

• All pupils can explain the process of longshore drift

• All pupils can identify the features created by longshore drift.

• All pupils can explain the features created by longshore drift.

Vocabulary

• Longshore drift• Bays• Shingle• sediment

What happens to the eroded material from the cliffs?

What type of wave deposits sediment?

Why are beaches important?Extra: can you classify the reasons as social,

environmental or economic?

Swanage Beach

How are these two pictures linked?

Is there anything to stop the sea from eroding the cliff?

What will happen to any buildings at the top of the cliff?

How are beaches formed?

Beaches form in sheltered environments, such as bays. When the swash is stronger than the backwash, deposition occurs.

Sometimes sand from offshore bars can be blown onto the shore by strong winds.

In such cases dunes may form – such as at Studland on the Dorset Coast.

Task

Explain why beaches are important.

• Beaches are important because………

How are pebbles and sand moved by the sea?

Backwash

Swash

If you tracked a pebble’s progress through swash and backwash where would it end up? Why?

In lesson 2 you learnt about Swash and Backwash

How is sediment transported along the coast?Can you predict what will happen when the animation is started?

This movement of sediment along the coastline is called longshore drift.

Direction of movement

swash

Backwash

Backwash is always at right angles to the beach

Longshore drift http://www.bbc.co.uk/learningzone/clips/3086.bb.wmv

TaskMake an annotated copy of the diagram showing longshore drift. The annotations should explain longshore drift.

Your annotations must include the following words:• Wave• Swash• Backwash• Constructive• Material

Backwash

Use the labels below to annotate a diagram showing how longshore drift occurs

Backwash

A constructive wave brings material to the beach

The swash moves the material diagonally up the beach

Backwash moves the material back down the beach. Gravity means it is at right angles to the beach.

Another constructive wave pushes material back up the beach

The process is continued meaning that the material “zig zags” along the beach

What other landforms does longshore drift create?

A bar e.g. Chesil Beach

A bar e.g. Chesil Beach

A spit

How are spits formed?Can you predict what will happen?

Task Produce a sequenced piece of writing to demonstrate how a spit is formed. Pages 78-79 may help.

How are spits formed?

What is a tombolo?

If a spit joins the mainland to an island it is called a tombolo.

At Chesil Beach in Dorset, the mainland is joined to the Isle of Portland.

Chesil Beach

Portland

From what direction was the photograph taken?

Name features X and Y.

Study the photograph.

X

Y

If a spit joins one part of the mainland to another it is called a bar.

For example, there is a bar at Orford Ness in Devon.

What is a bar?

Task Explain what a spit and tombola is.

Homework: due next lesson.

Explain the process of longshore drift. You may use a diagram to help with your answer (4)

Finally: Coastal landforms in Studland