S6E3d Currents, waves, and tides-Oh My!
1. Ocean water is always moving
2. current is a stream of water flowing like a river in the ocean.
3. ocean currents can carry warm water towards cold climates and can carry cold water towards warm climates
4. surface currents are caused by the wind.
5. global winds travel thousands of miles and last for weeks; caused by uneven heating between the equator and the north and south poles.
6. The trade winds-blow from the east, they are close to the equator and were used by sailors traveling to trade with other countries.
7. the westerlies- blow from the west, they are the strongest
around 40 degree latitude. They carry the weather across the United States.
9. ocean currents flow in a clockwise direction in the Northern Hemisphere. Currents flow in a counterclockwise direction in the Southern Hemisphere.
10. coriolis effect causes the winds and the currents to curve.
12. drift bottle- bottle containing a message that is dropped into a current to track its movement.
13. Gyre-surface currents that are wind driven and and move in large circular patterns
14. North Atlantic Current is a gyre- surface current that takes warm water up to Northern Europe and gives it a warmer climate
continental deflection-when a current changes direction because it flowing
towards a continent
15. density current-caused by the differences in cold and hot water and/or salty and fresh water.
16. salt water is more dense than fresh water so salt water will sink down below fresh water
17. cold water is more dense than warm water so cold water will sink down below warm water.
18. density will cause the movement of water just as surely as wind will cause movement.
19. upwelling-the vertical circulation in the ocean that brings deep, cold water to the surface.
20. upwelling brings nutrients up from the ocean floor which creates rich fishing grounds.
21. as seawater freezes, the salt is left behind causing the remaining water to be extra salty. The extra salty water is more dense and will sink, creating a density current.
22. rapid evaporation also causes density currents. When ocean water evaporates, the salt is left behind, making the remaining water salty and more dense.
23. waves-the regular up and down movement of water
24. crest is the highest point of a wave
25. trough is the lowest point of a wave
26. wavelength is the distance from one crest to the next.
27. wind causes waves.
28. frequency is the number of waves that occur in a certain period of time.
29. energy travels in the direction of the wave.
30. water particles do not move with the wave, they move in circles equal to the height of the wave
32. flood tide-the incoming, or rising tide
33. ebb tide-outgoing, or falling tide
34. Moon’s gravity causes most tides.
35. changing tides happen about every 6 hours and 15 minutes.
36. Spring tide is an extra high and extra low tide caused by the alignment of the Moon and the Sun.
37. Neap tide is smaller tidal change than normal caused by the Moon and Sun being on different sides of the Earth.
38. intertidal zone-the land that is exposed during low tide but is covered during high tide.