"Inspection of the Natural Waters in My Hometown" Environment and Us PPT Courseware 3

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"Inspection of the Natural Waters in My Hometown" Environment and Us PPT Courseware 3

What are the routine analysis indicators for water pollution?

The main routine analysis indicators of water pollution include:

(1) Odor is one of the sensory indicators to judge the quality of water. Clean water is odorless and only produces odor after being polluted.

(2) Water temperature is a physical indicator of water body. The water temperature rises. Indicates contamination from new sources of pollution.

(3) Turbidity Ground water turbidity is mainly caused by soil, organic matter, microorganisms and other substances. Increased turbidity indicates water contamination with colloidal substances. Our country stipulates that the turbidity of drinking water shall not exceed 5 degrees.

(4) pH value is the negative logarithm of the hydrogen ion activity in water. A pH value of 7 means that the water is neutral. Water greater than 7 is alkaline, and water less than 7 is acidic. The pH value of clean natural water is 6.5 to 8.5. If the pH value is abnormal, it means that the water body is polluted by acidity and alkalinity.

think

Compared with tap water and domestic sewage, are the natural waters in your hometown polluted? Analyze the reasons, why?

Ask the students to give suggestions on how to protect the water environment in their hometown.

What is light pollution? What harm does it do to the human body?

Internationally, light pollution is generally divided into three categories, namely daylight pollution, artificial daytime and colored light pollution.

White pollution: When the sun shines brightly, the glass curtain walls, glazed brick walls, polished marble and various paints and other decorations of buildings in the city reflect light, making them bright and dazzling. Expert studies have found that people who work and live in white light polluted environments for a long time will suffer varying degrees of damage to the retina and iris, and their vision will drop sharply. The incidence of cataracts is as high as 45%. It can also make people dizzy and upset, and may even lead to insomnia, loss of appetite, depression, physical weakness and other symptoms similar to neurasthenia.

In summer, the strong reflected light from the glass curtain wall enters nearby residential buildings, increasing the indoor temperature and affecting normal life. Some glass curtain walls are semicircular, and the reflected light can easily cause fires. Drivers driving under the scorching sun will be unexpectedly hit by the light reflected from the glass curtain wall, and their eyes will be strongly stimulated, which can easily cause a car accident.

Artificial daylight: After night falls, the advertising lights and neon lights on shopping malls and hotels are dazzling and dazzling. Some strong beams of light even reach into the sky, making the night look like daytime, which is the so-called artificial daylight. In such a "city that never sleeps", it is difficult to fall asleep at night, disrupting the body's normal biological clock, resulting in low work efficiency during the day. Artificial daylight can also harm birds and insects, and strong light may disrupt the normal reproduction process of insects at night.

Colored light pollution: Black lights, rotating lights, fluorescent lights and flashing colored light sources installed in dance halls and nightclubs constitute colored light pollution. According to measurements, the intensity of ultraviolet rays produced by black light lamps is much higher than that of ultraviolet rays in sunlight, and its harmful effects on the human body last for a long time. If people receive this kind of radiation for a long time, it can induce nosebleeds, tooth loss, cataracts, and even lead to leukemia and other cancers. Colored light sources dazzle people, which are not only harmful to the eyes, but also interfere with the central nervous system of the brain, making people feel dizzy, causing nausea, vomiting, insomnia and other symptoms. Scientists' latest research shows that colored light pollution not only damages people's physiological functions, but also affects mental health.

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"Inspection of the Natural Waters in My Hometown" Environment and Us PPT download:

"Inspecting the Natural Waters in My Hometown" Environment and Us PPT Download Part One: Introduction of New Lessons Is the water in the natural waters in my hometown polluted? What causes pollution? Let’s go check it out! Discuss in groups and think about what to pay attention to during the inspection...

"Inspecting the Natural Waters of My Hometown" Environment and Us PPT:

"Inspecting the Natural Waters in My Hometown" Environment and Us PPT Part One: Making a Plan Is the water in the natural waters in my hometown polluted? What causes pollution? Let’s go check it out! Preparation before the inspection activity 1. Discuss the plan of the inspection activity..

"Inspection of the Natural Waters in My Hometown" Environment and Us PPT Courseware 4:

"Inspecting the Natural Waters in Hometown" Environment and Our PPT Courseware 4 Give it a try. Examine the quality of the water around you and discuss it in class! Precautions for using the microscope 1. Take water and prepare a slide specimen. 2. Place. 3. To the light. 4. Raise the objective lens and place the glass...

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Update Time: 2024-09-30

This template belongs to science courseware Science Edition for Sixth Grade Science Volume 2 industry PPT template

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