"Our Water Resources" Source of Life - Water PPT Courseware 2

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"Our Water Resources" Source of Life - Water PPT Courseware 2

1. We live on a "water polo" with both abundant and scarce water resources.

1. 70.8% (about 3/4) of the earth’s surface is covered by water, and water resources are very abundant.

2. Various living organisms contain a large amount of water resources.

Human body is about 65%, jellyfish is about 95%, and fish is about 70%.

3. Available freshwater resources are only about 0.7%, mainly river water, freshwater lakes and shallow surface water. (Freshwater resources are in short supply)

4. Cherish precious water resources and save water.

Industrial water recycling

Adoption of new irrigation methods in agriculture (e.g. drip irrigation)

Use water for multiple purposes in life, take a shower instead of a bathtub

Turn off the faucet and so on.

Main uses of water

Agriculture: Water is the lifeblood of agriculture, and its consumption accounts for about 2/3 of the total fresh water consumed by humans.

Industry: washing, dissolving, heating, cooling, etc.

Life: laundry, cooking, toilet flushing, car washing, etc.

(Water is an important natural resource.)

The current situation of water resources is not optimistic

Although the total water reserves on the earth are large, 97.2% is seawater, and fresh water only accounts for about 2.53% of the earth's water reserves. Less than 1% of available fresh water resources are available. Coupled with uneven regional and temporal distribution, my country's per capita freshwater possession is less than 1/4 of the world average.

With the development of society, water consumption for human life and production continues to increase.

The intensification of water pollution has reduced the available water.

In today's world, about 2 billion people face fresh water crisis, of which 300 million people live in water shortages.

2. Water pollution and its prevention and control

1.Main sources of water pollution

(1) Arbitrary discharge of industrial "three wastes" (i.e. waste residue, waste water, and waste gas).

(2) Random discharge of domestic sewage.

(3) Urban domestic garbage accumulates everywhere.

(4) Unreasonable use of pesticides and fertilizers in agriculture.

2. Eutrophication of water bodies

(1) Characteristics: The content of nutrients such as nitrogen and phosphorus in the water is too high, and algae reproduce in large numbers in the water body.

(2) Phenomenon: "algae bloom" and "red tide".

(3) Anthropogenic sources: industrial wastewater, agricultural drainage, and domestic sewage.

(It is recommended to use phosphorus-free laundry detergent)

3. Prevention and control measures of water pollution

(1) Discharge of domestic sewage after treatment

(2) Industrial wastewater is discharged after being treated to meet standards

(3) Rational use of pesticides and fertilizers

(4) Recycling after centralized treatment of garbage

One stick, two low and three rely on

One post

The filter paper should be close to the inner wall of the funnel without leaving any air bubbles.

Second low

The edge of the filter paper in the funnel is lower than the edge of the funnel mouth

The liquid level in the funnel is lower than the edge of the filter paper

Three things to rely on

When pouring the liquid, the beaker is in contact with the glass rod

The end of the glass rod contacts the three layers of filter paper in the funnel

The lower end of the funnel is in contact with the inner wall of the beaker that receives the filtrate.

4. Hard water and its softening

1. Hard water: water containing more soluble calcium and magnesium compounds.

Soft water: Water with no or less soluble calcium and magnesium compounds.

2. Hard water is harmful

3. How to distinguish soft water from hard water

(1) Use soapy water: water with less residue and more residue is called soft water, water with less residue and more residue is called hard water. (easiest)

(2) Evaporation: water with slag is called hard water, and water without slag is called soft water.

4. Method to reduce water hardness: boiling (in daily life)

Distillation (most efficient)

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For more information about the "Source of Life Water Our Water Resources" PPT courseware, please click the "Source of Life Water ppt Our Water Resources ppt" tag.

"Our Water Resources" Source of Life - Water PPT Courseware 3:

"Our Water Resources" Source of Life Water PPT Courseware 3 Learning Objectives: 1. What is the volume fraction of fresh water in the earth's water resources? 2. What is my country’s per capita freshwater possession in the world? 3. Do you waste water? How to save water and prevent...

"Our Water Resources" Source of Life - Water PPT Courseware:

"Our Water Resources" The Source of Life Water PPT Courseware 1. We live on a water polo. 70.8% of the earth's surface is covered with water. 2. Life is inseparable from water. Various living organisms contain a large amount of water. Water accounts for 65% of the human body; for organisms living in water, water accounts for their body weight..

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Update Time: 2024-10-20

This template belongs to Chemistry courseware Cantonese Education Edition Ninth Grade Chemistry Volume 1 industry PPT template

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