الصف الرابع الابتدائي ساينس
ساينس رابعة ابتدائي

لينك تحميل الملزمة
https://drive.google.com/file/d/1Hnumnp61aRHYSLFJAHUS0LMHpoQcjvLj/view?usp=sharing

لينك تليجرام
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In This Video :
Some sources of pollution in big cities
1. Burning fuel produces smog, which pollutes the air.

2. Pesticides used on farms are mixed with water in canals and rivers when rain falls, this lead to pollution of soil and water.

3. Using chemicals in factories pollute the air and also the nearby water sources and soil.

Some effects (impacts) of air pollution on human's health
1. Smog from cars cause irritation of human's eyes and lungs.
2. Scientists have found that smog contains tiny particles that the human breathes in, these particles irritate the lungs, causing the damage of tissues of the respiratory system.
Harms of burning of fossil fuels on the environment
Burning fuel not only produces electricity but also pollutes the environment, where burning of coal and oil produces carbon dioxide gas which causes :

1. Acid rains
Carbon dioxide gas combines with water in the air to form carbonic acid , resulting in acid rains that cause :
- The death of trees.
- Decomposition and dissolving of some rocks including bricks of buildings.
- Chemical changes in the structure of
lakes causing the death of fish.
- Chemical changes in the structure of soil.

2. Global warming
Increasing the amount of carbon dioxide gas in the air forms a layer in the atmosphere that traps heat above the Earth 's surface causing a slow rise in the Earth's temperature , which is known as global warming.

How to reduce acid rains and global warming
The best solution to reduce acid rains and global warming is to rationalize
(decrease) the use of energy, where:

• As we reduce our consumption of energy, the amount of burning of fossil fuel to
generate energy decreases.

• As the amount of burning of fossil fuel decreases, the amount of carbon dioxide and other pollutants in the air which we breathe in will decrease.

بالتوفيق
مستر احمد الباشا