Unit 3 Oceanography Section 3: Currents, Waves, and Tides
Earth Science Mr. Margetan Ocean Currents Surface Currents Movement of water on the surface, primarily caused by winds Ocean Currents Longshore Currents Currents which run parallel to the shoreline due to energy released from waves Ocean Currents Upwelling Currents Occur when wind moves seawater at the surface and new water from below replaces it Critical Thinking #1 How might upwelling currents be beneficial to life in the ocean?Explain. Ocean Currents Deep Currents Move slowly beneath surface, primarily caused by differing water densities Critical Thinking #2 What processes might cause changes in density that form deep ocean currents? Ocean Currents Global Conveyor Belt A connected deep ocean current that circles the entire planet Waves Waves Up and down, circular movement of energy in water
Caused primarily by wind Also, disturbances in the ocean, earthquakes Critical Thinking #3 How are ocean waves similar to seismic waves?How are they different? Factors Influencing Wave Size
Strength of Wind Speed wind is blowing Fetch Distance wind is blowing Duration Length wind is blowing Parts of a Wave Crest Highest point on a wave
Trough Lowestpoint on a wave Wavelength Horizontal distancefrom crest to crest Wave Height Vertical distance fromcrest to trough How do Waves Break? Waves begin to change shape at a depth its wavelength Waves break at adepth of 1.3x itswave height Critical Thinking #4 Considering how waves break, how might the shape of the ocean floor influence the shape of waves? Types of Breakers Surging Breakers Waves roll into the shore, occurs at steep beaches Plunging Breakers Wavescurl and break, occurs atmoderate slope beaches Spilling Breakers Wavesbreak far from shore, occursat gentle slope beaches Tides Tides Daily changes in the level of the ocean surface
2 high tides and 2 low tides each day caused by gravitational pull of primarily themoon, but also the sun High Tides and Low Tides
High (Flood) Tides Occur on side of Earth facing and opposite the moon, due to both gravity facing and centrifugal force opposite Low (Ebb) Tides Occur on sides halfway between the moon Spring Tides and Neap Tides
Spring Tides = Highest and lowest tides, when moon and sun align Neap Tides= Small tidal range, when moon and sun are perpendicular Critical Thinking #5 Why are spring tides stronger than neap tides?Explain.