"Sandstorm" Changes in Ground Form PPT Courseware 2

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"Sandstorm" Changes in Ground Form PPT Courseware 2

Read the brief information and discuss:

Among the basic conditions for the formation of sandstorms, which conditions are related to human activities?

Small information

Sandstorm weather is severe weather in which strong winds raise sand and dust, making the air turbid, and horizontal visibility is less than 1,000 meters. The formation of sandstorms generally requires conditions such as abundant dust sources and strong winds. Sandstorms mostly occur in deserts, sandy areas and dry sandy exposed surfaces. The air here is easily heated, while the air above is relatively cold, causing warm air to rise and cold air to sink, forming air convection. When strong winds occur for a long time, it is easy to lift ground dust to high altitudes and be blown to other places by strong winds, forming sandstorms.

The meaning of sandstorm

Sandstorms, also known as sandstorms or dust storms, refer to weather phenomena in which strong winds blow up dust and sand from the ground, making the air very turbid and with horizontal visibility less than 1,000 meters.

Think about it:

What conditions do you think are needed for the formation of sandstorms?

It mostly occurs in deserts, sandy areas, and arid sandy bare surfaces.

The air is easily heated, resulting in the up and down flow of warm and cold air and the effect of strong winds.

Conditions for the formation of sandstorms

1. Sand and dust source

2.Strong wind

3. Unstable air

Dangers caused by sandstorms

1. Deaths of humans and animals, collapse of buildings, and reduction in agricultural production.

Sandstorms are no less harmful to people, animals and buildings than typhoons and tornadoes. In the past five years, my country's northwest region has been hit by sandstorms more than 20 times, causing economic losses of more than 1.2 billion yuan and more than 200 people dead and missing...

2. Air pollution and topsoil loss.

There are at least 38 chemical elements in sandstorm dust. Its occurrence greatly increases the concentration of atmospheric solid pollutants, causing long-term and potential harm to the atmospheric environment, soil, and agricultural production in the origin and surrounding areas. Especially after the meager topsoil on which crops depend is scraped away, the barren land will seriously affect crop yields.

Read the text, draw the diagram and answer the following questions

1. What did you find from the table?

1.) The number of sandstorms is increasing year by year

2.) The area of ​​land desertification is constantly expanding.

2. Why does this happen? Tell me what you think.

1.) Natural causes: Earth’s greenhouse effect, climate anomalies and other factors.

2.) Man-made causes: over-exploitation of natural resources and excessive deforestation caused by population expansion,

Over-cultivation of land is the main cause of sandstorms and increases their intensity and frequency.

protective forest

1. Establish protective forests to prevent the movement of soil and dust.

2. Plant a large number of trees and establish a good ecological barrier.

3. Plant flowers, trees and flowers in the city to increase the green area.

4. Scientific grazing and protecting grassland.

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For more information about the "Changes in Ground Forms and Sandstorms" PPT courseware, please click on the "Changes in Ground Forms ppt Sandstorms" ppt tag.

"Sandstorm" PPT courseware on changes in ground form:

"Sandstorm" PPT courseware on changes in ground form. Based on the above pictures, what do you find are the main phenomena when sandstorms occur? 1. Strong winds stir up dust and sand on the ground; 2. There is a lot of sand in the air; 3. The air is quite turbid; 4. The weather is gray and cannot be seen...

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Update Time: 2024-10-20

This template belongs to science courseware E-education edition sixth grade science volume 1 industry PPT template

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