Waves and Currents

Which of these BEST describes the cause of waves in the ocean?

• high and low tides
• evaporation of water
• wind blowing across the surface of the ocean
• ridges and trenches on the bottom of the ocean

What is the cause of most ocean surface currents? 

• gravity
• the wind
• the moon
• upwellings

A tsunami is an unusually large wave caused by

• an earthquake or volcano
• increased gravitational pulls when the sun and moon line up
• a heat wave
• extreme winds   

The two main parts of a wave are?

• Wavelengths and wave heights.
• Swells and whitecaps.
• Crests and troughs.
• Rises and dips.

The currents of the Earth's oceans are caused by 

• marine organisms and volcanic eruptions.
• global winds and differences in temperature and salinity.
• waves and earthquakes along tectonic plate boundaries.
• disturbances by submarines and large ships

An earthquake causes a tsunami because force from the quake?

• meets the force of currents flowing in a different direction.
• Blows surface water away from the shore.
• Pulls water down toward the source of the quake.
• Pushes a large body of water up from the ocean floor.

What does an ocean’s salinity refer to?

• the depth of the ocean trenches.
• the height of the waves. 
• the temperature level of the water.
• the level of minerals in the water.

Surface ocean currents such as the Gulf Stream?

• Move warm water from lower latitudes to higher latitudes.
• Transport cold water from one pole to the other.
• Are formed in parts of the ocean where water density is greatest.
• Move in straight paths across the ocean.

Why do waves increase in height as they approach the shore? 

• The waves begin to interact with the ocean floor.
• The water’s density decreases because it is warmer near the shore. 
• The wave particles speed up as they approach the land.
• The waves are forced into narrow inlets of land.

Surface currents are caused by?

• Floods
• Warm water.
• Winds.
• The equator.