How to estimate four parameters of stable distribution in R language

We learned the weathering of rocks by various natural forces and the influence of weathering on the surface. This lesson guides students to understand the erosion of land by running water. The falling of raindrops is the beginning of the erosion process. Some of the precipitation seeps into the ground, some evaporates or is absorbed by plants, and the rest of the rain flows on the ground to become runoff. The force of raindrops can break up and splash soil particles, and runoff flows on the ground to take away these particles. Due to the gravity, runoff and the material it carries move downwards, and constantly merge with other runoff in the process of traveling, and the strength increases, taking away more soil and forming gullies in the soil, and the gullies converge with each other to form large gullies. When the water flows through the gully, it is already very powerful, which can take away the soil and rocks, thus widening the gully ... This is how the water constantly erodes the surface.

Students often see rainfall, but they don't necessarily think that it will erode the land and change the terrain. Through the simulation experiment of "rain" and the observation of land and runoff when "rain" falls, this lesson understands the erosion effect of running water on soil. On this basis, what factors affect the degree of land erosion is put forward, and students can speculate and design experimental schemes according to their own experience to explore.

learning process:

1. Introducing new lessons

1. Rain is a frequent weather phenomenon. When it rains, the rain falls on the land.

2. Will rain affect the land?

3. What will happen to the land?

4. What will happen to the rain?

2. How does the rain affect the land

1. Let's do an experiment

1. Build a sloping terrain with a small amount of sand and stones in a rectangular plastic box, pat it tightly with a small shovel, and then build a vertical "cliff" on the edge of the soil.

2) Prepare another beverage bottle, and punch some holes in the bottle cap to make a sprinkler. Fill the beverage bottle with water and cover it.

3) put the box with the "cliff" on the waste newspaper, spread a plastic film on the newspaper, and raise one end of the box.

4) squeeze the sprinkler by hand to let the water spray out. Pay attention to let the "rain" fall on the slope soil as much as possible, and observe what happens when the "rain" falls on the "terrain".

2. Communicate our findings in the experiment

1. What happened to "rain" when it fell on the land?

2) What happened to the land (soil) when it rained? Think about why?

3) Compare the "runoff" and "rainwater" in the water receiving container. What are their differences? Can we explain why?

4) What else have we found?

changes in soil

3. Summary: The force of raindrops can break up and splash soil particles. When the rain flows on the ground, it carries away these particles and some soil is taken away? This is erosion. When raindrops fall to the ground, soil erosion begins.

3. Factors affecting erosion

1. In nature, the terrain of the surface is often not very flat, the degree of vegetation coverage is different everywhere, and the rainfall in the sky is also large and small.

2. Will the slope of the land, the presence or absence of plant cover and the rainfall affect the degree of soil erosion? Tell us about our speculation and reasons.

3. Can we design experiments for research?

1) which influencing factor did our group choose to study?

2) shall we set up a control group?

3) What conditions should be the same between the experimental group and the control group? What conditions need to be changed?

4) what kind of experimental equipment do we use? What is the experimental device like?

4. "Design of factors affecting soil erosion" scheme reference.