"Oxygen Cycle and Carbon Cycle in Nature" PPT

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"Oxygen Cycle and Carbon Cycle in Nature" PPT

Part One Content: Independent Learning

1. What are the components of air? The volume fraction of oxygen is ______, and the volume fraction of carbon dioxide is ______.

2. In nature, all living things are constantly breathing, taking in ______ and releasing ______. Photosynthesis of plants requires absorbing ______ and ______, making organic matter, and releasing ______ at the same time.

3. Write the text expressions for photosynthesis and respiration respectively.

Photosynthesis: ____________________.

Respiration: ____________________.

Oxygen cycle and carbon cycle in nature PPT, part 2 content: Oxygen cycle in nature

discuss

1. How would you feel if you stayed in a closed room for a long time?

Shortness of breath, dizziness, palpitations

2. What methods can be used to increase the dissolved oxygen content in the water in the fish tank? Why?

Discussion and analysis: What are the main ways of carbon cycle in nature?

1. CO2 → _____ effect → _____ substance → _____ effect → CO2

2. CO2 → _____ function → _____ substance → _____ absorption → oxidation in the body → CO2

3. CO2 → _____ action → _____ matter → animal and plant residues → microbial decomposition → CO2

4. CO2→ _____ function →_____ substances →animal and plant residues →coal, petroleum, natural gas →_____→ CO2

Oxygen cycle and carbon cycle in nature PPT, Part 3: Greenhouse effect

Causes of greenhouse effect

Carbon dioxide is like greenhouse glass. The light from the sun can pass through well to the earth and increase the temperature of the ground. However, the radiation from the ground rarely penetrates this layer of carbon dioxide, making it difficult for the ground heat to dissipate, making it have a thermal insulation effect. .

What are the pros and cons of the "greenhouse effect"? What measures can we take to prevent the intensification of the "greenhouse effect"?

Benefit A moderate "greenhouse effect" can ensure a constant temperature on the earth, suitable for the survival of animals and plants.

Disadvantages In the past century, due to the extensive use of fuel and the sharp reduction of forest area due to deforestation, the amount of carbon dioxide in the atmosphere has increased rapidly, resulting in an intensification of the greenhouse effect, leading to global warming to a certain extent, and causing A series of negative consequences.

Measures: Promote afforestation, use hydrogen energy, hydro energy, solar energy and other fuels that do not produce carbon dioxide.

Oxygen cycle and carbon cycle in nature PPT, Part 4: Consolidation exercises

1. The following conditions will increase the concentration of carbon dioxide in the atmosphere ( )

A. Use lime water to absorb carbon dioxide in the air

B. The number of cars increases

C. Develop solar energy and water energy to replace coal, oil and other fuels

D. Planting trees

2. The carbon cycle in nature is completed through CO2. The main way to absorb carbon dioxide in nature is ( )

A. Respiration B. Transpiration

C. Photosynthesis D. Decomposition

3. In nature, the main ways to consume oxygen are ( )

A. The combustion of various fuels B. The respiration of animals and plants

C. Microorganisms oxidize and decompose organic matter D. All of the above

Keywords: Zhejiang Education Edition eighth grade science PPT courseware for the second volume free download, oxygen cycle and carbon cycle in nature PPT download, .PPT format;

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Update Time: 2024-11-21

This template belongs to science courseware Zhejiang Education Edition Eighth Grade Science Volume 2 industry PPT template

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