"Care for Water Resources" Water in Nature PPT Courseware 7

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"Care for Water Resources" Water in Nature PPT Courseware 7

1. Water resources owned by humans

1. In what forms does water exist on the earth? Approximately what percent of the earth's surface is covered by water?

2. What is the largest water storage reservoir on earth?

3. The total water storage capacity is: 1.39 × 1018m3, most of which is occupied by ocean water, and fresh water accounts for only 2.53%. However, most of the fresh water is distributed in glaciers, and only 30.4% of the fresh water can be developed and utilized by humans. Ask people What percentage of the total water can the fresh water used by the class account for?

4. What is the total water storage capacity in my country? Where does it rank in the world? How much water is available per capita?

Do the math:

The total known water storage capacity is: 1.39 × 1018m3, most of which is occupied by ocean water, and fresh water accounts for only 2.53%. However, most of the fresh water is distributed in glaciers, and only 30.4% of the fresh water can be developed and utilized by humans. Try to find out what human beings can What percentage of the total water volume is used?

Total Amount: Rich

1.39×1018m3

Available fresh water: limited to less than 1% of the total water volume

【Think about it】

71% of the earth is covered with water. Why are there still many countries and regions in the world facing water shortage crisis?

Causes of water shortage:

1. Available freshwater resources are limited (less than 1% of the total water volume) and are unevenly distributed.

2. As the population increases, water consumption increases.

3. Water pollution is serious.

4. Water wastage is serious.

According to statistics, more than 80 countries and more than 2 billion people in the world are facing fresh water crises. Among them, more than 300 million people in about 26 countries live in a state of water shortage.

China: The total amount of water resources is 2.8×1012m3, ranking 6th in the world, but the per capita water amount is only 2300m3, ranking in the 80s in the world, and about a quarter of the world's per capita water amount. And the distribution is uneven, with abundance in the south and shortage in the north.

practise

Water is the most basic component of all living organisms. People must replenish a certain amount of water every day to maintain the water balance in the body. How much water does an adult need per day under the following circumstances?

(1) Eat food containing about 750ml of water every day, and use about 350ml of water produced by the oxidation of food;

(2) The amount of water eliminated from the body in the form of urine, sweat, exhalation and stool every day is: 1700ml, 500ml, 400ml, 150ml.

The volume of water that needs to be replenished is:

(1700ml+500ml+400ml+150ml)-(750ml+350)=1650ml

2. Protect water resources

1. How do we protect water resources?

2. What is water pollution? What are its sources?

3. What are the dangers of water pollution?

4. What are the measures to prevent and eliminate water pollution?

What is water pollution

Water pollution: A large amount of pollutants are discharged into a water body, exceeding the self-purification capacity of the water body, deteriorating the water quality, destroying the ecological balance of the water body and its surroundings, causing losses and threats to human health, life, and production activities.

1. Main sources of water pollution:

(1) Industry: arbitrary discharge of industrial wastewater and waste residue;

(2) Agriculture: Unreasonable use of chemical fertilizers and pesticides;

(3) Domestic: arbitrary discharge of domestic sewage.

2. Dangers of water pollution:

①Affects industrial, agricultural and fishery production

② Destroy aquatic ecosystems

③Hazardous to human health

3. Measures to prevent water pollution:

(1)In industry: industrial wastewater is discharged after treatment.

(2) In agriculture: rational use of chemical fertilizers and pesticides, and promotion of the use of farmyard manure.

(3) In daily life: Domestic sewage should be discharged after treatment, and the use of phosphorus-containing detergents is prohibited.

(4) Strengthen water quality monitoring

Exercise: There is a faucet installed in a pool. If each faucet drips 1 drop of water per second, and an average of 20 drops is 1ml, try to calculate how many liters of water the pool can leak every day and night?

The arc on the upper right side of the emblem represents water pipes and faucets. A drop of water dripping from the faucet is carefully caught by an outstretched palm. The emblem cleverly uses the homophony of joint and festival to vividly and vividly embody the meaning of "water saving" in it.

Please every citizen remember this emblem and cherish every drop of water like the apple of our eye.

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For more information about the PPT courseware "Nature's Water and Protecting Water Resources", please click on the Nature's Water ppt and Protecting Water Resources ppt tag.

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Update Time: 2024-11-23

This template belongs to Chemistry courseware People's Education Press Ninth Grade Chemistry Volume 1 industry PPT template

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