| A | B |
|---|
| ocean current | movement of ocean water that follows a regular pattern |
| Thor Heyerdahl | Norwegian explorer who theorized that inhabitants of Polynesia originally sailed from Peru |
| Kon Tiki | handcrafted raft made of materials available to ancient Peruvians and sailed by Thor Heyerdahl across the Pacific from Peru to Polynesia in 1947 |
| surface current | horizontal movement of ocean water caused by wind and occurring near ocean's surface |
| global winds, Coriolis effect, continental deflections | 3 factors controlling surface currents |
| The Gulf Stream | one of the longest surface currents; transports 25 times more water than all rivers of world |
| Global winds | winds that blow across Earth's surface, creating surface currents in the ocean |
| Coriolis effect | apparent curving of the path of a moving object from an otherwise straight path due to the Earth's rotation |
| continental deflection | the changing of direction of a surface current when the current meets a continent |
| deep current | streamlike movement of ocean water deep below the surface; form in parts of the ocean where density increases |
| decreasing temperature, increasing salinity through freezing, increasing salinity through evaporation | factors influencing the formation of deep currents |
| Antarctic Bottom Water Current | deepest , densest current |
| North Atlantic Deep Water Current | less dense current than Antarctic Bottom Water |
| upwelling | movement of deep, cold, nutrient-rich water to the surface |
| El Nino | change in the water temperature in the Pacific Ocean that produces a warm current every 2 to 12 years |
| crest and trough | 2 parts of a wave |
| crest | highest point of a wave |
| trough | lowest point of a wave |
| wavelength | distance between 2 adjacent wave crests or troughs |
| wave height | vertical distance between crest and trough of wave |
| wave period | time between passage of two wave crests (or troughs) at a fixed point |
| wave speed | wavelength divided by wave period |
| deep water waves | waves that move in water more than 1/2 their wavelength |
| shallow water waves | waves that have moved into water shallower than 1/2 their wavelength |
| breakers | waves that are pulled over by gravity, crashing toward ocean floor |
| breaker zone | area off shore where waves first begin to break |
| surf | area between breaker zone and the shore |
| undertow | subsurface current that is near shore and pulls objects out to sea underneath new incoming waves |
| longshore current | water current that travels near and parallel to the shoreline |
| whitecaps | white, foaming waves with steep crests that break in the open ocean |
| swells | rolling waves that move steadily for great distances across the ocean |
| tsunami | a giant ocean wave that forms after a volcanic eruption,, submarine earthquake, or landslide when a large volume of wate is suddenly moved up and down |
| storm surge | local rise in sea level near the shore caused by strong winds from a storm such as a hurricane |
| tide | periodic rise and fall of water level in the oceans and other large bodies of water |
| Sir Isaac Newton | published his theories on the principle of gravitational pull in 1687 |
| high tide | bulging of the Earth toward the moon (and on the side of Earth directly opposite the moon) |
| low tide | areas of global ocean where water is pulled away during high tides |
| tidal range | difference in levels of ocean water at high tide and low tide |
| spring tide | tide of increased range that occurs two times a month, at the new and full moons |
| neap tide | tide with the smallest daily tidal range; occurs during first and 3rd quarters of the moon |
