Types of Wave

The size of a wave depends on its fetch, wind speed and wind duration above the water. True or false?

• True

• False

Answer explanation

The size of a wave depends on its fetch, wind speed and wind duration above the water.

Waves are a disturbance on the surface of the sea or ocean, in the form of a moving ridge or swell. True or false?

• True

• False

Answer explanation

Waves are a disturbance on the surface of the sea or ocean, in the form of a moving ridge or swell.

What is the fetch of a wave?

• The strength of the wind blowing over the ocean or sea

• The distance a wave has travelled

• The length of time wind has blown over the ocean or sea

Answer explanation

The fetch of a wave is the distance it has travelled.

True or false? As waves move into shallow water, they begin to stack up as frictional drag with the seabed increases, the base of the wave is slowed down, so the top part is travelling faster. This causes the wave to tilt, break and move towards the shore in the surf zone

• True

• False

The movement of a wave up a beach is known as what?

• Swash

• Backwash

• Wave crest

• Swoosh

Answer explanation

The movement of water up a beach is known as swash.

Identify the type of wave is shown in the picture.

• Destructive

• Constructive

Answer explanation

The image shows a destructive wave. Destructive waves destroy beaches. The waves are usually very high, have a short wavelength and are very frequent. The wave has a steep front and is typically over 1 metre high. The backwash has less time to soak into the sand. As waves continue to hit the beach there is more running water to transport the material out to sea.

Identify the type of wave is shown in the picture.

• Destructive

• Constructive

Answer explanation

The image shows a constructive wave. Constructive waves have a long wavelength and a low-frequency (8–10 waves per minute). They have a low wave height (typically under 1 metre). The wavefront is gently sloping and gains a little height, breaks and spills onto the beach. Water spreads a long way up the gently sloping beach.

Which of the following are characteristics of constructive waves?

• Constructive waves have a long wavelength and a low-frequency (8–10 waves per minute). They have a high wave height (typically under 1 metre). The wavefront is gently sloping and gains a little height, breaks and spills onto the beach. Water spreads a long way up the gently sloping beach.

• Constructive waves have a long wavelength and a low-frequency (8–10 waves per minute). They have a low wave height (typically under 1 metre). The wavefront is gently sloping and gains a little height, breaks and spills onto the beach. Water spreads a long way up the gently sloping beach.

• Constructive waves have a short wavelength and a low-frequency (8–10 waves per minute). They have a low wave height (typically under 1 metre). The wavefront is gently sloping and gains a little height, breaks and spills onto the beach. Water spreads a long way up the gently sloping beach.

Which of the following are characteristics of destructive waves?

• Destructive waves destroy beaches. The waves are usually very high, have a short wavelength and are very frequent. The wave has a steep front and is typically under 1 metre high. The backwash has less time to soak into the sand.

• Destructive waves destroy beaches. The waves are usually very high, have a short wavelength and are very frequent. The wave has a steep front and is typically over 1 metre high. The backwash has less time to soak into the sand.

• Destructive waves build beaches. The waves are usually very high, have a short wavelength and are very frequent. The wave has a steep front and is typically over 1 metre high. The backwash has less time to soak into the sand.

When are destructive waves most common?

• Summer

• Autumn

• Spring

• Winter

Answer explanation

Destructive waves are more common in winter when the wind is stronger.