Soil covers the surface of the earth's lithosphere. The formation of soil is the result of rock weathering and biological action. The whole rock is weathered into rubble, and the rubble will become smaller and smaller as it continues to change. When decaying plants and animals are mixed with rock fragments, the mixture is called soil. In the soil, we can easily find traces of rock changes and the remains of animals and plants.

Soil is common to students, but they may never consider where it comes from, let alone where it comes from rocks. This lesson is followed by the last lesson, focusing on guiding students to observe and analyze the composition of soil. On the one hand, it is to find evidence that soil comes from rock weathering and biological action, on the other hand, it is to understand the significance of soil to life.

Rock and soil are important substances that make up the earth's surface. The formation and remodeling of topography is the result of various external forces acting on rock and soil, in which the main objects of erosion and deposition are soil and rock. Finding the settlement experiment of soil components not only helps students to understand what is in the soil, but also enables students to have a certain understanding of the settlement phenomenon and layered settlement, paving the way for later classes.

This lesson is mainly divided into two parts. The first part is "looking for the composition of soil"; The second part is "soil and life".

Analysis of learning situation

Students are no strangers to soil, but they have no systematic understanding. Students need further observation and research to correctly identify soil components.

Teaching objectives

Knowledge goal:

1. The weathering of external forces and the action of organisms will eventually turn rocks into soil.

2. Soil contains particles of different sizes formed by weathering of living bodies and residues of rocks, animals and plants, humus, water and air.

3. When water flows, it can carry soil particles, and when water is still, the carried substances will also be deposited. Generally speaking, heavy particles are deposited first and light particles are deposited later.

4. Soil is closely related to biological survival and human production and life.

Process and method:

① Find out the composition of soil through observation and experiment. ② Soil components are divided into several layers according to particle size by sedimentation. ③ Synthesize the information obtained by various methods to have a correct understanding of soil composition.

Emotions, attitudes and values:

Emotion, attitude and values: realize the significance of soil to life and human production and life.

Teaching emphases and difficulties

Key points: Find out the composition of soil through observation and experiment.

Difficulties:

Weathering and biological action will eventually turn rocks into soil.