Waves, Currents, and Tides
Waves, Currents, Tides (WCT) Cornell Notes Key Terms Notes Summary:
Engage Study Jams: Waves and Currents The class “WAVE” How did we move? Did we actually move around the classroom with the wave?
Introduction to Waves
Waves Caused by: Wind Earthquakes A disturbance which moves through or over the surface of a fluid Mostly caused by winds Caused by: Wind Earthquakes Gravitational force of the Moon and Sun. Form of great energy
Wave Characteristics Parts of a Wave Crest = high point Trough = low point Height = vertical distance from crest to trough Wavelength = Horizontal distance between crest to crest or trough to trough
A wave is the movement of energy through water. OCEAN WAVES A wave is the movement of energy through water.
What causes waves? Waves form from wind Waves form out in the open ocean, and travel inwards to the shore.
What are the effects of waves? Waves can erode and deposit sediment, changing the shape of the beach
BIGGER winds create BIGGER waves
Tsunamis Tsunamis (underwater waves) are giant ocean wave caused by earthquakes, landslides, and volcanic eruptions beneath the ocean floor As tsunamis approach the shore, the waves come closer together and grow into a mountain of water
Tsunami Waves
The energy from waves can carry materials to the seashore The energy from waves can carry materials to the seashore. Beaten-up pieces of shells and rocks can be carried to a beach by pounding waves. In Australia, a huge amount of sea foam was once carried in!
Wave Movement When a wave passes through the ocean, individual water molecules move up and down but they do not move forward or backward.
Tides Tides are the movement of ocean water at the shore when it rises and falls during the day High and Low tides occur 2 times per day
Types of Tides Spring Tide - Moon and sun are in direct line with one another - Results in unusually high tidal range Tidal Range = vertical distance between high & low tides 2x’s/month
Neap Tide sun and moon are at right angles Pulls cancel each other out – causes a weak pull unusually low tidal range 2 x’s / month
What causes tides? The gravitational pull of the moon and sun on Earth’s water High tides occur when the moon and sun are lined up on the same side of the Earth
What are the effects of Tides? High tides: Water level is high on shore Low tides: Water level is low on shore
Currents
What are ocean currents. http://www. brainpop Ocean Current: mass of ocean water moving from one place to another. 2 types of currents: Surface current Thermohaline (Deep water) current
What causes Surface Currents? Surface currents: horizontally flowing currents caused by global and seasonal winds Usually warmer-water Direction of currents is caused by Coriolis Effect http://www.classzone.com/books/earth_science/terc/content/visualizations/es2401/es2401page01.cfm?chapter_no=visualization
Coriolis Effect Coriolis Effect: Earth’s rotation causes objects in the N. hemisphere move clockwise, objects in S. hemisphere to move counterclockwise
Demo: Deep Ocean Currents http://www.youtube.com/watch?v=I8kToTROCHA
What causes deep ocean currents? Temperature = least dense = floating water Temperature = more dense = water sinks Thermo = heat, haline = salt Deep ocean currents are vertical currents caused by differences in density and temperature ( water masses rise and fall) Usually colder water
This diagram is a view of the deep ocean currents of the world.
What are the effects of currents? Surface currents form large circular patterns called gyre. Currents affect the climate of a location Warm-water currents warm up climate, cold water currents cool down climate
“Global Conveyor Belt” When combined with surface currents it results in a conveyor-belt movement of water around the globe!
Check for Understanding When the temperature of these currents decrease, what will happen to the density? The density will increase Will cold ocean water sink toward the bottom or rise to the surface? Cold water will sink the bottom because it is more dense (Convection!!!!)