The small bright pieces in the thermos flask with water everywhere are harmful to people

Most of today's thermos are aluminum-plated, not mercury. But even aluminum can no longer drink water that seeps into the foil flakes. That is to say, aluminum foil is also harmful to the human body.

The inner tank of the thermos is also called a dewar, and Li Wuyin is made of two layers of glass, with a vacuum in the middle. In order to ensure the quality of the process, there is also a graphite cushion block between the two orange god layers. Because it fits snugly to the glass layer, it can be reflected to the mouth of the bottle, and you can see the small highlights of the banquet.

Rest assured, what is in between the two layers of glass will not be harmful to the human body. If it's really harmful, you're not alone.

When pouring water into the kettle, the sound emitted by the kettle is formed by the vibration of the air column in the kettle, and the sound produced by the air column is different depending on the length of the air column;

When pouring water, the water becomes fuller and fuller, the air column becomes shorter and shorter, the frequency becomes higher and higher, and the pitch gradually rises;

Therefore, we can judge whether the water in the kettle is full according to the different sounds of different air columns;

Therefore, choose B

When we pour boiling water into a thermos flask from a kettle, we can tell if the water in the bottle is almost full by the change in the pitch of the sound;

In the process of pouring boiling water into the thermos, more and more water in the thermos flask, the shorter the air column becomes, the easier it is to vibrate, the higher the frequency, and the higher the pitch

Therefore, the answer is: the defeat of the hidden tone is dry Zheng tone, tone; High

1. Look: Take a glass of water with a transparent glass, look at the light to see if there are fine substances suspended in the water, let it stand for three hours, and then observe whether there is sediment at the bottom of the cup.

2. Smell: Use a glass to get a glass of water as far away from the faucet as possible, and then smell it with your nose to see if there is a smell of bleaching powder (chlorine) in the section wheel, if you can smell the smell of bleaching powder (chlorine), it means that the residual chlorine in the water from Tonghu is excessive.

3. Taste: Drink hot boiled water, whether there is a smell of bleaching powder (chlorine), if you can smell the smell of bleaching powder (chlorine), it means that the residual chlorine in the tap water exceeds the standard.

4. View: Make tea with tap water, observe whether the tea turns black after overnight, if the tea turns black, it means that the iron and manganese in the tap water are seriously exceeded, and a reverse osmosis water purifier with the function of removing iron and manganese filter should be used for purification.

5. Product: Drink boiled water, the taste has an astringent feeling, if there is, it means that the hardness of the water is high, and the water softener should be equipped with food-grade ion exchange resin for softening treatment.

6. Check: Check the water heater and boiling kettle at home, whether there is a layer of yellow scale on the inner wall, if there is, it also means that the hardness of the water is high, (the content of calcium and magnesium salt is too high), and you should also hold the water softener equipped with food-grade ion exchange resin for softening treatment as soon as possible.

The tone is determined by the vibrational frequency, the more water, the shorter the column of air inside the bottle, and the higher the frequency; Therefore, as the water level continues to rise, the pitch gradually increases

So the answer is: elevated.

The tone is determined by the vibration frequency, the more water, the shorter the column of air in the bottle, the higher the frequency, and it is by virtue of this that the water is almost full;

Therefore, C

A This question examines the tone, and knowing that it is the vibration of the air column that affects the sound emitted by the thermos is the key to solving this problem. The sound emitted in the thermos flask is produced by the vibration of the air column above, and the pitch is related to the speed of the vibration of the sound emitter, the faster the object vibrates, the higher the pitch. The more water, the shorter the column of air in the bottle and the higher the frequency; Therefore, the height of the water level can be judged by the height of the tone. So choose A