"What's in the Soil" The land where plants live PPT courseware 4

Description

"What's in the Soil" The land where plants live PPT courseware 4

(1) Life in the soil - soil organisms

observe

Observation time

Observation location

Environmental characteristics

Environmental factors such as soil moisture, looseness, temperature, light, plant growth conditions, etc.

soil organisms

Earthworms, snails, spiders, mites, centipedes, ants, mice, mole crickets, bacteria, fungi, actinomycetes

Brief analysis (interrelationship between biological species and dominant species’ life and environment)

Microorganisms, animals and plants living in the soil are collectively called soil organisms.

(2) Non-living substances in soil

Requirements: Choose dry soil - dry soil contains more air, and the experimental effect is obvious. In moist soil, many spaces have been occupied by water, and the air content will become less.

Experimental steps:

1. Put a piece of soil in the beaker (the volume of the soil is V), and slowly pour water until the water surface completely submerges the soil. Record the volume of water added to the beaker. Remember it as V1.

2. Replace the soil with an iron block equal to the volume of the soil and repeat the above experiment. Record the volume of water added. Remember it as V2.

3. The volume fraction of air in the soil is approximately (V1-V2)/V

discuss

1. In the experiment, why do the volumes of the soil and iron blocks have to be the same?

2. The two large beakers used to hold soil and iron must be consistent in shape or volume. What is the purpose of this?

3. Why do the amounts of water added to the same volume of iron and soil differ?

4. Given a metal container, an appropriate amount of water, and a large enough measuring cylinder, how do you measure the approximate volume fraction of air in the soil?

Other methods of measuring air volume fraction in soil:

Method 1: Use a metal container to dig a piece of soil in the soil, and then use a measuring cylinder to add water to the metal container. The amount of water injected at this time is equivalent to the volume of air. Then clean the metal container, then add water to the container, and measure Find the volume of the container, which is equivalent to the volume of the soil, so you can find the volume fraction.

Method 2: Use a metal container to dig a piece of soil and place it in a measuring cylinder filled with water. The amount the liquid level rises at this time is the volume of the non-air part of the soil. By measuring the volume of the metal container, you can measure the soil. The volume fraction of air.

Visible: There are very fine crystals on the evaporating dish. Explain that there are inorganic substances in the soil (substances that can be dissolved in water but cannot be burned. These inorganic salts are needed for plant growth).

summary

1. There are three types of substances that make up soil: solid, liquid, and gas. The solid part of soil is mainly composed of mineral particles and humus, of which mineral particles account for about 95% of the solid part.

2. Moisture in the soil is a necessary condition for plant growth, and soil air is the source required for plant root respiration and microbial life activities.

(3) The formation of soil ~ the weathering of rocks

The surface of the earth's crust and the various rocks that make up the earth's crust are damaged or changed, which is called weathering of rocks.

Rocks gradually turned into gravel and sand under the influence of long-term wind and rain, alternation of cold and heat, and the action of organisms, and finally formed soil containing sand, organic matter, water, air and other substances. This is the process of rock weathering.

summary

The formation from rock to soil is an extremely complex process involving the interaction of multiple natural factors over a long period of time. That is, there is the process of rocks growing from large to small and the accumulation of organic matter in rock particles.

1. Weathering: natural external forces - wind, water flow, and water forming ice;

Thermal expansion and contraction - sudden drops in heat cause rocks to burst

The role of plants and animals

2. The corpses and excrement of plants and animals accumulate between rock particles and are an important source of soil humus and organic matter.

3. Soil formation is still proceeding normally, and the speed of soil formation is extremely slow - pay attention to protect cultivated land.

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"What's in the Soil" PPT courseware:

Qingdao edition of the second volume of third grade science, what is in the soil PPT courseware, the first part: classroom experiment

Experimental steps:

1. Put small clods of soil into water. What do you see? Explain what is in the soil?

2. Stir the soil and let it sit for a while.

"What's in the Soil" PPT:

Qingdao version of the third grade science volume 2, what is in the soil PPT, the first part of the content: methods to find the components of the soil. What I saw with the naked eye in the soil was that the soil was moist, with unbroken pebbles, grass roots and insects, and a magnifying glass with pebbles. Sand grains and powders of different sizes...

"What's in the Soil" The land where plants live PPT courseware 3:

"What's in the Soil" The Land Where Plants Live PPT Courseware 3 What life is in the soil? Earthworms can break through hard, compact soil, making it easier for plant roots to expand and for air and water to enter the soil more easily. Ants are insects that burrow in the soil. Burrowing animals,...

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Update Time: 2024-10-02

This template belongs to science courseware People's Education Press third grade science volume 2 industry PPT template

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