Sand dunes

Views:
 
Category: Education
     
 

Presentation Description

Jaisalmer Rajasthan

Comments

Presentation Transcript

PowerPoint Presentation:

1 Sand dunes By Janardan Prasad

PowerPoint Presentation:

2 A sand dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind. SAND DUNES

PowerPoint Presentation:

3 DUNE FORMATION 1.The sand moves until it meets a slight obstruction, such as a clump of grass, which deflects the wind and allows the sand grains to drop. 2.Thus a slight mound or hummock is created. 3.Wind moves sand up to the top of the pile until the pile is so steep it collapses under its own weight and falls down the leeward side called the slip face

PowerPoint Presentation:

4 4.The collapsing sand comes to rest when it reaches just the right steepness to keep the dune stable. 5.This angles is called the angle of repose and is usually 30-34 degrees DUNE FORMATION

PowerPoint Presentation:

5 Sand on the Move!

PowerPoint Presentation:

6 Migrating dunes The repeating cycle of sand inching up the windward side to the dune crest and falling down the leeward side allows the dune to inch forward in the direction the wind blows

PowerPoint Presentation:

7 The Desert Triangle Rajasthan Desert comprises the three cities - Jaisalmer, Bikaner and Jodhpur which is commonly known as the desert triangle. These three cities are entwined in such a way that they form a desert circle. The cultural and historical significance and the glorious past of these cities have marked Rajasthan as 'the most colourful desert in the world'.

PowerPoint Presentation:

8 THANK YOU

authorStream Live Help