Sand dunes
The diagrams delineate the formation of sand dunes. Overall, this natural-occurring process comprises three main stages, beginning with the distribution of sand grains over dry and damp surfaces, followed by the accumulation of sand particles, and ending with sand dunes formed on wet grounds that alter the wind direction.
Looking initially at the first two diagrams, wind deposits sand on both dry and moist grounds. Under the wind force, sand particles are packed on top of one another on the wet surface until a small mound starts to form. It can be seen that there is no indication of mound formations on the dry surface.
Turning to the last diagram, sand piles up on the windward side once the first mound forms. The sand particles keep accumulating on both sides of the mound, gradually turning it into a dune. The emergence of sand dunes from wet grounds diverts the wind, forcing it up on the windward side and down on the leeward one. Finally, this change in the wind direction necessitates the recurring aggregation of grains on damp areas, repeating the process.
Essay Breakdown
Structure:
Introduction:
[1] The diagrams delineate the formation of sand dunes. [2] Overall, this natural-occurring process comprises three main stages, beginning with the distribution of sand grains over dry and damp surfaces, followed by the accumulation of sand particles, and ending with sand dunes formed on wet grounds that alter the wind direction.
- Summary what the process details – the formation of sand dunes.
- Write an overview, mentioning how many main phases are – summarise the beginning, middle, and final stages of the detailed process.
Body:
Paragraph 1:
[1] Looking initially at the first two diagrams, wind deposits sand on both dry and moist grounds. [2] Under the wind force, sand particles are packed on top of one another on the wet surface until a small mound starts to form. [3] It can be seen that there is no indication of mound formations on the dry surface.
- Describe the first stage of the detailed diagram.
- Describe how small mounds form on the wet surface.
- Give more details about the mound’s formations on a different surface.
Paragraph 2:
[1] Turning to the last diagram, sand piles up on the windward side once the first mound forms. [2] The sand particles keep accumulating on both sides of the mound, gradually turning it into a dune. [3] The emergence of sand dunes from wet grounds diverts the wind, forcing it up on the windward side and down on the leeward one. [4] Finally, this change in the wind direction necessitates the recurring aggregation of grains on damp areas, repeating the process.
- Describe the last phase of the diagram – including the formation of the first mound.
- Describe how a dune is formed.
- Show how the emergence of sand dunes alters the wind’s direction.
- Show how the cycle is repeated.
Vocabulary:
The diagrams delineate the formation of sand dunes. Overall, this natural-occurring process comprises three main stages, beginning with the distribution of sand grains over dry and damp surfaces, followed by the accumulation of sand particles, and ending with sand dunes formed on wet grounds that alter the wind direction.
Looking initially at the first two diagrams, wind deposits sand on both dry and moist grounds. Under the wind force, sand particles are packed on top of one another on the wet surface until a small mound starts to form. It can be seen that there is no indication of mound formations on the dry surface.
Turning to the last diagram, sand piles up on the windward side once the first mound forms. The sand particles keep accumulating on both sides of the mound, gradually turning it into a dune. The emergence of sand dunes from wet grounds diverts the wind, forcing it up on the windward side and down on the leeward one. Finally, this change in the wind direction necessitates the recurring aggregation of grains on damp areas, repeating the process.
Vocabulary Highlight:
- formation (n): the action of forming something
- natural-occurring process: the process that occurs in nature
- accumulation (n): the process of gradually increasing or getting more and more of something over a period of time
- particle (n): an extremely small piece of matter
- alter (v): to change
- initially (adv): at the beginning
- deposit (v): to leave something somewhere
- pack on top of one another (v): to place on top of one another
- divert (v): to change direction
- indication (n): to show, point, or make clear in another way
- leeward (adv): on or towards the side of something that is sheltered from the wind
- necessitate (v): to make something necessary
- aggregation of (n): the accumulation, collection or amassing of something
Reading:
Further Reading about this topic can be found here:
https://education.nationalgeographic.org/resource/dune
Listening:
Further Listening about this topic can be found here:
