1. Earth’s Waters Chapter 4.1 Pages 114-121
Wave Action
Earth’s Waters Chapter 4.1
Pages

2. Wave Formation (P114-115½ ) What is a Wave?
How do most waves form?
List the 3 things wave size depends on.
Do waves move water toward shore?
What actually happens to objects as a wave passes?

3. Wave Formation (P114-115½ ) What is a Wave?
The movement of energy through a body of water
How do most waves form?
When winds blowing across the water’s surface transmit their energy to the water
b) List the 3 things wave size depends on.
The strength of the wind, how long it blows, and the distance it travels.

4. Wave Formation (P114-115½ ) 2. Do waves move water toward shore?
No, they only transfer energy. Otherwise, water would pile up on the coasts.
What actually happens to objects as a wave passes?
As a wave passes, water particles move in a circular path. The deeper below the wave, the smaller the circle.

5. Draw a picture like on p116 and label these parts.
Describing Waves (P )
Define a Crest.
Define a Wavelength.
Define Frequency.
Define a Trough.
Define Wave Height.
What happens to waves as they reach shore?
What is Undertow?
*Or*
Draw a picture like on p116 and label these parts.

7. Describing Waves (P116-117) Crest – highest part of a wave
Wavelength - horizontal distance between crests
Frequency – number of waves that pass a point in a certain amount of time
Trough – lowest part of a wave
Wave Height – vertical distance from crest to trough.

8. Describing Waves (P )
6. What happens to waves as they reach shore? The wave begins scraping the ocean floor, causing friction and slowing the wave. Wave height increases as wavelength decreases. At a certain height, the wave topples or breaks on shore 7. What is Undertow? Force of gravity pulling water back to the ocean.

9. The Shore & Erosion (P118-120)
What effect does Longshore Drift have?
How can you escape a Rip Current?
What is Erosion?
How does erosion affect beaches?
Describe 3 ways to reduce beach erosion.
Are Groins a positive choice?

10. The Shore & Erosion (P118-120)
What effect does Longshore Drift have?
Waves hit the beach at an angle, transporting sand along the beach.
How can you escape a Rip Current?
Rush of water that flows back through a narrow opening – swim parallel to beach
2. What is Erosion?
Carrying away of sediments
How does erosion affect beaches?
Causes the shoreline to move further inland.

11. The Shore & Erosion (P118-120)
3. Describe 3 ways to reduce beach erosion.
1. Groins – a wall that stretches out from the beach
2. Dunes – hills of sand covered with plants, which hold it together
3. Barrier Beaches – small island-like sand deposits parallel to beach
Are Groins a positive choice? No, they increase the amount of erosion down the beach.

12. Tsunamis (Page 121)
How do Tsunamis compare to regular waves in size and strength?
Describe how tsunamis form.

13. Tsunamis (Page 121)
How do Tsunamis compare to regular waves in size and strength?
Can have a wavelength of 200km and a crest 20m high
Describe how tsunamis form.
An underwater earthquake sends a massive pulse of energy through the water around it.

14. Section 4.1 Review (Page 141) Define Key Terms for Section 4.1
Know the wave diagrams on pages 116 & 117