1. Chapter 13 Oceans

2. 13.1 Ocean Currents
What is the difference between a current and a wave?
Waves are on the surface of water
(i.e. - ocean waves at a beach)
Currents are below the surface
(i.e. – EAC – East Australian Current)

3. 13.1 Ocean Currents
surface currents – currents near the surface of the ocean (warm and/or cold currents)
3 things can change the direction of surface currents:
continental deflections – currents change direction because they hit a continent
global winds – global winds can blow a current a different direction
Coriolis effect – the Earth rotating changes the direction of winds and currents (they do not go straight because the Earth is turning in circles)
(i.e. – throwing a ball onto a spinning merry-go-round)

4. 13.1 Ocean Currents
deep currents – currents far below the surface of the ocean (all cold currents)
Deep currents travel along the ocean floor

5. 13.2 Ocean Waves
El Niño – a change in the water temperature in the Pacific Ocean that produces a warm current (more severe)
La Niña – a change in the eastern Pacific Ocean in which the surface water temperature becomes unusually cool

6. 13.2 Ocean Waves
upwelling – happens near the shore where cold water rises to replace the warm water that has been blown out to sea by wind
Upwelling helped to cause the El Niño phenomenon

7. 13.3 Ocean Waves crest – highest point of a wave
trough – lowest point of a wave
wave length – the distance between two wave crests or two wave troughs
wave height – the distance between the wave crest and the wave trough
wave period – the time it takes for two waves to pass over a fixed point

8. 13.3 Ocean Waves
breaker zone – the near-shore area where waves are at their highest point right as they begin to break or tumble downward
Surfers surf on the breaker zone
surf – the near-shore area where waves have broken and the water is calmer
white caps – white foaming waves with steep crests that break in the open ocean
Heavy winds or storms can cause white caps
swells – steady waves out in the open ocean

9. 13.3 Ocean Waves
tsunamis – large waves that form in the ocean due to an underwater earthquake, volcanic eruptions, landslides, underwater explosions, or a meteorite hitting the ocean
storm surge – a rise in sea level near the shore that was caused by strong winds, hurricanes, or a tsunami

10. 13.3 Tides high tide – when the water level rises near the shore
low tide – when the water level lowers near the shore