TidesEW Chapter

4.2Pages 123-

126

Cause of TidesPage 123

• What are Tides?– Describe the 2 types of Tides.–What objects and force cause Tides?– Draw a picture of the location of the

tidal bulges like the one on Page 123.

Cause of TidesPage 123

• What are Tides?• Daily rise and fall of water on coastlines– Describe the 2 types of Tides.– High tide is when water reaches its highest point,

Low tide the lowest point–What objects and force cause Tides?– The gravity from the moon causes tides (Sun, too)– Draw a picture of the location of the

tidal bulges like the one on Page 123.

Daily Tidal CyclePage 124

• How often do tides occur?• What factors affect the height of the

tide?

Daily Tidal CyclePage 124

• How often do tides occur?• High tides occur about ever 12 hours & 25

minutes• What factors affect the height of the

tide?• Landforms (capes, islands), depth and speed of

water.

Cape Cornwall, UK

Cape Canaveral, FL

Tidal Cycle124-125

• What is Spring tide?– Draw a picture of the alignment of

the Earth, Moon & Sun to illustrate.• What is Neap tide?– Draw a picture to illustrate.

Tidal Cycle124-125

• What is Spring tide?• Greatest range between low & high tide– Draw a picture of the alignment of

the Earth, Moon & Sun to illustrate.• What is Neap tide?• Least difference between high & low tide– Draw a picture to illustrate.

Tidal Energy125-126

• Explain how tides can be used to create electricity.–Why is this system not always useful?

• If you were the captain of a ship, why would it be useful to know the time of the tides?

Tidal Energy125-126

• Explain how tides can be used to create electricity.

• During high tide, water floods into a basin. As the water retreats during low tide, it spins turbines to produce electricity–Why is this system not always useful?– Only works in locations where tide difference is

large and energy must be stored for when needed.

Tidal Energy125-126

• If you were the captain of a ship, why would it be useful to know the time of the tides?

• So you know when a port is / is not accessible and do not run aground