"Exploring the factors causing land erosion" Earth's surface and its changes PPT courseware

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"Exploring the factors causing land erosion" Earth's surface and its changes PPT courseware

1. Communicate and discuss experimental plans

1. Group communication and presentation of experimental plans.

2. Evaluate, modify or improve the experimental plan (see Plans 1, 2, and 3 below).

3. Thinking: What issues should we pay attention to during the experiment?

Option 1: The impact of land slope on erosion

Research question: Does the size of the land slope affect the degree of soil erosion?

My guess: The greater the slope, the greater the erosion; the smaller the slope, the less erosion.

Experimental equipment: rectangular plastic box, soil, sprinkler, water...

Identical conditions: Except for the different slope sizes, other conditions are the same. (There are no plants, rainfall size, soil looseness, rainfall height, etc.).

Different conditions: the experimental group has a large slope; the control group has a small slope.

Experimental method: Use a watering can to "rain" at the same height above the experimental group and the control group, and observe the degree of soil erosion.

Option 2: Impact of plant coverage on erosion

Research question: Does the presence or absence of plant cover affect the extent of soil erosion?

My guess: erosion is greater without plant cover, and erosion is less with plant cover.

Experimental equipment: rectangular plastic box, soil, sprinkler, water, vegetation...

Identical conditions: All conditions are the same except for the presence or absence of plant cover. (Slope size, rainfall size, rainfall height, soil looseness, etc.)

Different conditions: the experimental group has plant coverage; the control group has no plant coverage.

Experimental method: Use a watering can to "rain" at the same height above the experimental group and the control group, and observe the degree of soil erosion.

2. Experiments to explore erosion

1. Preparation before the experiment: Pay attention to fairness and standardization of operation in the experiment; prepare the experimental device.

2. Group experiments, teacher tour guidance.

It is required to use a container to catch the "runoff", and carefully observe and record the phenomena during the experiment.

3. Communication: What phenomena did we see in the experiment, and what do these phenomena indicate?

4. Summary: What factors are related to the degree of land erosion? (Fill in the empty box on P59)

size of slope

With or without plant coverage

amount of rainfall

Through experiments, we found:

Heavy rainfall causes more serious land erosion than small rainfall;

Erosion without plant coverage is more severe than with plant coverage;

Land with steep slopes is more susceptible to erosion than land with smaller slopes.

3. Expansion and extension

1. Guess where in nature the land is most prone to erosion?

2. Watch the pictures and videos of "Yellow River Water" and "Soil Erosion".

Requirement: Think while watching:

How will the terrain change as the land erodes?

What kind of disasters will erosion bring to us?

Why is the water of the Yellow River so yellow?

Because the Yellow River flows through the Loess Plateau and undergoes severe erosion, the river water carries a lot of loess and silt, which is why it appears so yellow. Loess erosion produces a large amount of sediment, turning the Yellow River flowing here into the river with the highest sediment content in the world. The Yellow River transports an average of 1.6 billion tons of sediment downstream every year. On average, the sand content per cubic meter of river water reaches 37.6 kilograms.

What disasters does erosion bring?

When flash floods occur, the force of the water carries away many stones and washes away many plants. Such flash floods rush down, destroying farmland, houses, and roads, triggering mudslides and landslides, causing losses to people's lives and property.

Of course, erosion is not all harmful. For example, in the lower reaches of rivers, the fertile soil brought by the river water will gradually accumulate into alluvial plains, adding new land for people. This issue will be discussed in the next lesson on the role of rivers.

What did you learn from studying this lesson?

Through study, we know that human activities can increase or decrease the extent of land erosion. If afforestation and scientific and rational use of land are used, the degree of land erosion will be reduced. If there is indiscriminate deforestation and overgrazing, the degree of land erosion will be aggravated.

Class summary:

1. The size of the slope, the presence or absence of vegetation coverage, the amount of rainfall, etc. will affect the degree of land erosion.

2. Erosion is constantly changing the topography of the earth's surface, causing land loss and affecting our production and life.

3. Protecting forests and returning farmland to forests can reduce land erosion.

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"Exploring the Factors of Land Erosion" Earth's surface and its changes PPT download:

"Exploring the Factors of Land Erosion" The Earth's Surface and Its Changes PPT Download Part One Content: Exchange, discussion, and discussion of experimental plans. The impact of the slope of the land on erosion. The impact of plant coverage on erosion. The impact of rainfall on erosion.. . ... ...

"Exploring the Factors of Land Erosion" Earth's surface and its changes PPT:

"Exploring Factors Caused by Land Erosion" The Earth's Surface and Its Changes PPT Part One Content: Communication and Discussion of Experimental Plans We have initially formulated a research plan on the degree of soil erosion by rainwater and what factors are related, and we will share our experimental plans with our classmates. I..

"Exploring the Factors of Land Erosion" Earth's Surface and Its Changes PPT Courseware 2:

"Exploring Factors Affecting Land Erosion" Earth's Surface and Its Changes PPT Courseware 2 Teaching Objectives Exchange research plans on factors affecting land erosion; Experience research experiments on factors affecting land erosion; Name and explain what kind of land is in nature Most vulnerable to intrusion...

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Update Time: 2024-10-01

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