Unit 4.1 Waves and Tides PDF

UNIT 4.1 WHAT CAUSES WAVES AND TIDES LESSON OBJECTIVES By end of this lesson, students will be able to : 1. List the factors affecting wave intensity 2. Outline what causes wave to be formed 3. Identify how tides are formed  01. WAVE  What is Ocean wave? o Regular pattern of...

UNIT 4.1 WHAT CAUSES WAVES AND TIDES LESSON OBJECTIVES By end of this lesson, students will be able to : 1. List the factors affecting wave intensity 2. Outline what causes wave to be formed 3. Identify how tides are formed  01. WAVE  What is Ocean wave? o Regular pattern of motion o Movement of energy through water which makes water particles to move o When the wind blows on the surface of water, waves are formed (air and water interface)  HOW IT WORKS? o Water is not carried away with the motion of wave o The water particles move in a circular motion o Water particles bump into the next particles and passes the energy along through the water KEY FACTORS INFLUENCING WAVE INTENSITY Fetch Wind Duration Wind strength Depends on The distance Stronger how long the wind blows wind blows. the wind, over open bigger the water without waves interruption or changes in its direction  02 WHAT HAPPEN WHEN WAVES REACH THE COAST  Rearrange the movement of wave approaching the coast 1. This creates a breaking wave 2. When the water is in contact with the sea bed, it exerts a strong frictional force on the base of the wave 3. As the wave approaches the coast, it encounters contact with the sea bed 4.As it approaches the coast, it breaks over 5. As waves get closer and closer to the coast, the friction gets bigger 6.Waves travel in circular motion  Correct Sequence 1. Waves travel in circular motion 2. As the wave approaches the coast, it encounters contact with the sea bed 3. When the water is in contact with the sea bed, it exerts a strong frictional force on the base of the wave 4.As waves get closer and closer to the coast, the friction gets bigger 5. As it approaches the coast, it breaks over 6.This creates a breaking wave  03 WAVES AND INTERACTION AT COASTLINE  Uprush Backwash Movement of water Movement of water and sediment up a down the beach beach  TWO WAYS OF INTERACTION CONSTRUCTIVE DESTRUCTIVE When the uprush is When backwash is bigger than the larger than the uprush, backwash, materials get more material is eroded pushed up and from the beach accumulated on the It carries materials away beach from the beach This gives a gentle These waves are beach slope generated from large Created by low wave storms, which have high height and low wave and frequent waves frequency Constructive waves Destructive waves  04 TIDES  What are tides? Regular rise and fall of sea level As the tide comes in, the level of water on beach rises (high tide) As the tide goes out, the level of water on the beach goes down (low tide)  05 WHAT CAUSES HIGH TIDE AND LOW TIDE? --A---- G.R.A.V.I.T.Y  The biggest influence on Earth’s tides is the gravity of moon Moon’s gravity pull is smaller than Earth Since, the distance of moon is located so close to the Earth, its gravity pull is very strong causing high tides  HIGH TIDE As the moon’s gravity pulls on the water, it creates bulge on both sides of the Earth The bulge is created on side of Earth facing the moon This leaves a bulge of water on the opposite side of Earth This bulge is what we call as high tide As the part of Earth rotates into the bulges of water, we will experience the high tide  LOW TIDE The water on the side of Earth facing away from moon has less or weak pull In the areas where the oceans don’t bulge, is where we experience low tides  FREQUENCY OF TIDES Every high tides occur 12 and a half hours apart Two high tide and two low tide happens every 24 hours 50 minutes DONE!