Chapter 16 Test Review

Place these notes in your Meteorology Notebook.

Strong steady winds blowing over dry topsoil are conditions most likely to cause a dust storm. Video

A strong wind can carry clay and silt in the atmosphere over very long distances, even over oceans.

Deep hollows known as blowouts tend to form in areas where the climate is dry and vegetation is patchy.

Sands are more abrasive than silts and clays because sand grains tend to be larger and harder.

The shape of a ventifact gives information about the direction of prevailing winds.

Loess particles are small enough to be moved and deposited by the wind.

Where winds blow steadily from the west, the steepest slope of a sand dune will be on the east side.

The following can affect the shape of a sand dune:

• The steadiness of the wind

• The supply of sand

• The amount of vegetation present

Types of Sand Dunes:

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Most water waves are caused by winds.The highest lake waves cannot be as big

as the highest ocean waves because lakes have shorter fetch.

The period of a wave is the time it takes for one wavelength to pass a given point.

A particular wave has a wavelength of 30 meters and a period of 5 seconds. What is its speed?

30 meters5 seconds

= 6 meters per second

As waves pass, an object floating in deep water will bob up and down as the wave passes.

Wave refraction occurs when the section of a wave in shallower water slows down.

Headlands wear away more quickly than bay shorelines because wave energy is concentrated on headlands.

In shallow water a wave breaks when its lower part slows down, causing its upper part to move ahead.

Beach drift is the movement of sand down a beach in a zigzag pattern.

Strong, dangerous surface currents that can carry swimmers out from shore are rip currents.

Beach sand on a coral island is likely to consist primarily of calcite fragments.

Most irregular shorelines appear to have formed when coastal areas were flooded by the sea.

The diagram shows a shoreline where approaching waves are refracted, or bent, until they approach the shore more head-on. Shade the area where erosion is likely to be occurring fastest. Circle the area where sand is most likely to be deposited to form a beach. Draw an arrow showing the direction of the longshore current between points A and B. (4 points)

Shade the area where erosion is likely to be occurring fastest.

Circle the area where sand is most likely to be deposited to form a beach.

Draw an arrow showing the direction of the longshore current between points A and B. (4 points)

Essay #1

Describe how individual sand particles move as an entire sand dune migrates. What can prevent a dune from migrating?

As wind blows against the windward side of a migrating sand dune, individual sand particles are carried over the top. Over time this allows the particles to fall onto the leeward side moving the entire dune leeward. A dune may not migrate if the wind does not blow consistently in a particular direction. Vegetation can also hold a dune in place.

Essay #2

Compare a beach made of sand with one made of pebbles. What factors may account for the difference in the makeup of the beaches?

Over time, sand and clay on a beach are washed away by ocean waves. A sandy beach generally occurs where the sea floor has a gentle slope, and a constant supply of sand is delivered by rivers. A pebble beach generally occurs where the sea floor is steeper, and both sand and clay are washed away.