Sand Dunes
What image comes to mind when you think about the world’s great deserts? In movies and music videos, sand dunes are often used to represent desert environments. There is a reason deserts are so commonly dotted with sand dunes. As you noticed in the previous activity, wind blows the sand into piles to make dunes, especially in deserts.
Based on the sand activity, what is necessary for a sand dune to form?
Sand dunes need three things to form:
- an adequate supply of loose sand
- wind to blow the sand
- something that causes the sand to settle like a rock or clump of grass
Sand blows in the wind until some obstacle stops it. Where wind velocity decreases, sand grains are deposited to form a dune. Dunes migrate downwind and can completely obliterate anything in their paths. They can cover forests, block streams, and bury villages.
