32 terms

Currents, Waves and Tides - 6th grade


Terms in this set (...)

A large stream of moving water that flows through the ocean, carry water great distances, moves water at the surface of the ocean, also move deep water
Surface currents are caused by
Winds (mainly)
Warm surface currents originate (start) near the _____.
Why do surface currents move in circular patterns?
Because of the rotation of the Earth on its axis- The effect of Earth's rotation on the direction of winds and currents is called the Coriolis Effect
Which way do currents move in the Northern Hemisphere?
the right (clockwise)
Which way do currents move in the Southern Hemisphere?
the left (counter clockwise)
the largest and most powerful surface current in the North Atlantic Ocean, caused by strong winds from the west
Gulf Stream
What type of surface current is the Gulf Stream? (Warm or Cold)
The pattern of temperature and precipitation typical of an area over a long period of time
How do surface currents influence the climate of land near the coast?
Surface current warms or cools the air above it, influencing the climate of the land near the coast
How does the Gulf Stream affect the climate along the east coast of the United States?
The Gulf Stream carries warm water from the Tropics to the east coast of North America and causes the climate near the coast to be warmer than the climate inland
These currents move deep below the surface of the ocean and are caused by differences in density (temperature and salinity).....
Deep Currents
The density of water depends on its ___________ and ___________.
Temperature and salinity
Would you expect salinity to be high or low in a rainy ocean region near the mouth of a river? Why?
It would be lower, because freshwater is being added to saltwater- decreasing salinity of the water
What happens to the density of ocean water when the salinity of the water increases? Does the water sink or rise? Why
The water becomes more dense and sinks
Which is more dense (Warm water) or (Cold water)?
Cold water is more dense than warm water
Describe three ways the density of ocean water can increase:
1. When the temperature of ocean water decrease it becomes more dense and sinks
2. When the salinity of ocean water increases through freezing the water becomes more dense and sinks
3. When the salinity of the ocean water increases through evaporation, the salt is left behind and the water becomes more dense and sinks
Most waves form when__________ blowing across the water's surface transmit their energy to the water.
The size of a wave depends on what three things.
1. Strength of the wind- stronger winds create larger waves
2. The length of time the wind blows- the longer the winds blows the larger the wave
3. The distance over which the wind blows- winds blowing across longer distances build up bigger waves
The ______________ of the wave moves toward the shore, but the ____________ remains where it was.
1. energy
2. water
Draw and label the parts of a wave: crest, trough, wavelength, and Wave Height.
Trough: The low mound of water that is part of a wave; also refers to the rarefaction, or low pressure part of a sound wave
Wave height: The vertical distance of an ocean wave between the top of the wave crest and the bottom of the next trough
Crest: The high mound of water that is part of a wave; also refers to the condensation or high-pressure part of a sound wave
Wavelength: The horizontal distance between successive wave crests or other successive parts of the wave
What happens to the wavelength and the wave height as the wave approaches the shore?
The wave height increases and the wave length decreases
The rise and fall of Earth's waters on its coastlines
What force causes the tides to occur on Earth's surface?
Why does the moon's gravitational pull have a greater influence on Earth's waters when compared to the Sun? The Sun is the most massive body in our Solar System
The Moon is closer to the Earth
How many high tides and low tides occur each day (24 hour period)?
2 high tides and 2 low tides
The difference between the water levels during high and low tides
Tidal Range
In which phases of the moon do Springs Tides occur?
New moon and Full Moon
Why is the tidal range the greatest during a Spring Tide?
The combined gravitational pull of the Sun and Moon
In which phases of the mood do Neap Tides occur?
First Quarter and Third Quarter
Describe the positions of the Sun, Earth, Moon, and tidal bulge during Spring Tide
The sun moon and earth are lined up with either the moon between the earth and sun or the earth between sun and moon.
Describe the positions of Sun, Earth, Moon, tidal bulge during a Neap tide
Right angle alignment of all three.