Wind as an Agent of Change

Practice Bell Quiz• 1. Winds of at least _________ km/h are needed to

move sand grains.

• 2. The side of a ventifact that faces the steady wind direction wears into a smooth flat surface called a __________.

• 3. If the bottom of a blowout reaches the water table, what can stop further deflation? ____________

• 4. How is loess different from sand? (Compare grain size and travel mechanism)

• 5. The ends of a barchan sand dune point ____________.

• 6. The ends of a parabolic sand dune point ____________.

• 7. A transverse sand dune is ______________ to the direction of the wind, where as longitudinal sand dune is ____________.

• 8. Another name for the leeward side of a sand dune is _____________.

Dust Storm in Texas

Ventifacts:

Mushroom or Toadstool Rocks

Desert Pavement

Blowouts

Loess in China

Four Types of Sand Dunes

Parabolic Barchan

Transverse Longitudinal

Ripples on Windward side

Steep slope on Leeward side

Migration of Sand Dunes

Have a good