Poisoning must be dealt with promptly

In general food contamination incidents, people who eat contaminated food become ill at the same time or one after another. Although the symptoms can be different, it is difficult to tell whether they are poisoned or unwell. If you don't know what to do, you can call the local poison control center for help. Experts there will provide free guidance and assistance on poison prevention and first aid, as well as special antidote drugs and poison testing services. In most cases, you can handle it at home by inducing vomiting, taking adsorbent drugs, resting and other measures under the guidance of experts from the Poison Control Center, or with the help of relatives and friends. In severe cases, experts will also guide you to a professional unit for treatment.

Fingerprint inspection

Principle: Iodine will sublimate into iodine vapor when heated. Iodine vapor can dissolve in secretions such as oil on your fingers and form brown fingerprints.

Supplies: test tubes, rubber stoppers, medicine spoons, alcohol lamps, scissors, white paper, iodine.

Experimental steps: 1. Take a piece of clean, smooth white paper, cut it into a paper strip about 4 cm long and no wider than the diameter of the test tube, and press a few fingerprints on the paper strip with your fingers. 2. Use a medicine spoon to take a grain of iodine the size of a sesame seed and put it into the test tube. Suspend the paper strip in the test tube (be careful not to stick the side with the fingerprint on the tube wall) and plug it with a rubber stopper. 3. Heat the test tube containing iodine slightly above the flame of the alcohol lamp. Stop heating immediately after iodine vapor is generated and observe the fingerprints on the paper strip.

Courses on some new methods of producing hydrogen

Liang Yinghao, Textbook Research Institute

In recent years, scientists from various countries have developed some new methods of producing hydrogen. Scientists have also tested some new methods to produce hydrogen. Some of these new methods are now introduced as follows: hydrogen is produced by reacting porcelain with water. Scientists from Tokyo Institute of Technology in Japan produced hydrogen by reacting ceramics with water at 300°C. They heated the carbon nickel ferrite (CNF) to 300°C in a flow of argon and nitrogen, and then used an injection needle to inject water onto the CNF so that the water came into contact with the hot CNF to produce hydrogen. Since CNF returns to its inactive state after water decomposition, the ferrite can be used repeatedly. In each reaction, an average of 2 cubic centimeters to 3 cubic centimeters of hydrogen can be produced per gram of CNF. Hydrogen glucose deoxygenase is an enzyme extracted from microorganisms. The Oak Ash National Laboratory in the United States extracted glucose deoxygenase from thermoplasmic lactic acid bacteria. Thermoplasmic lactic acid bacteria were first discovered in low-temperature retort coal slag in American mines. Glucose deoxygenase extracts hydrogen from glucose with the help of nicotinamide adenine dinucleotide phosphate (NADP). In the process of producing hydrogen, NADP strips a hydrogen atom from glucose, turning the remaining material into a solution of hydrogen atoms. Production of Hydrogen from Bacteria Many primitive lower organisms can also release hydrogen during their metabolism. For example, many bacteria can release hydrogen gas under certain conditions. Japan has discovered a bacterium called "Trichobacter rubrum" that is an expert at producing hydrogen. This bacteria can be cultured in a glass vessel by using starch as raw material and adding some other nutrients to make a culture solution. For every 5 millimeters of starch nutrient solution consumed, 25 milliliters of hydrogen gas can be produced.

Producing hydrogen with green algae

Scientists have discovered a new way to make green algae produce hydrogen on demand. Scientists at the University of California, Berkeley, say that green algae is one of the oldest plants known to mankind and has developed the ability to live in two completely different environments through evolution. When green algae lives in normal air and sunlight, it photosynthesizes like other plants. Photosynthesis uses sunlight, water and carbon dioxide to produce oxygen and the chemicals plants need to stay alive. However, when green algae lack sulfur, a key nutrient, and are placed in an oxygen-free environment, the green algae will fall back on another way of life in order to survive. In this case, the green algae will Hydrogen gas is produced. According to scientists, 1 liter of green algae culture solution can produce 3 ml of hydrogen per hour, but researchers believe that the efficiency of green algae in producing hydrogen can be increased by at least 100 times.

Artificial snowfall

Since ancient times, it will snow when God is happy, and it will not snow when God is unhappy. Is there a way to make God let it snow according to human needs? There is a way, and this is artificial snowfall.

For water vapor in the sky to turn into rain and snow, it must meet two conditions. One is that it must have a certain degree of water vapor saturation (mainly related to temperature), and the other is that there must be condensation nuclei. Therefore, artificial snowfall must first have clouds in the sky. Without clouds, it is like a skillful woman cannot make a meal without rice, and it cannot snow. Clouds that can make snow fall are "cold clouds" that are below 0℃. In the cold clouds, there are both small water droplets where water vapor condenses, and small snow crystals where water vapor condenses. But they are very small and light. If there are no conditions for continued growth, they can only be suspended in the air like smoke and dust, and it is difficult to fall down. We often see large chunks of clouds in winter, but no snowflakes are floating down. This is because the snow crystals that make up these clouds are too small to overcome the buoyancy of the air, and their precipitation ability is very poor. If some particulate matter is sprayed into the clouds to promote the snow crystals to grow quickly enough to overcome the buoyancy of the air and fall down, this is the contribution of artificial snowfall.

What substances can be sprayed to promote the rapid growth of snow crystals? In the early days, people used many interesting methods to show their magic. These methods mainly include: setting fires on the ground and releasing large amounts of smoke and dust into the sky; using cannons to attack clouds; using kites to fly high into the clouds, and then electrifying the kites to discharge sparks; flying into clouds by airplane to spray liquid water droplets and dust particles . However, the results of these methods are not ideal. It wasn't until 1946 that people discovered that putting tiny particles of dry ice into cold clouds could form millions of snow crystals. On November 3 of that year, someone on a plane sprinkled dry ice pellets onto the top of altocumulus clouds with a temperature of -20°C, and found that snow fell from the clouds.

The dry ice mentioned here is not ice frozen by water, but a solid state of carbon dioxide, much like compacted snow in winter. The temperature of dry ice is very low, below -78.5°C. Spray the dry ice crystals into the cold cloud like a goddess scattering flowers. Each carbon dioxide crystal becomes a sharply cold center, prompting the water vapor, small water droplets and small snow crystals in the cold cloud to quickly gather around it and condense. Huacheng's larger snowflakes fell. How to spread these condensation nuclei into clouds? Most modern people use cannons, put chemicals in cannonballs, and then use the cannons to launch them into the clouds. However, this method sprays unevenly, wastes a lot of medicine, and increases the cost of artificial snowfall. Others put them in clay rockets and let the rockets fly into the clouds to spray them.

Symptoms of pesticide-contaminated food poisoning

Whether people will develop poisoning symptoms after eating food with pesticide residues and the severity of the symptoms depend on the type of pesticide and the amount of pesticide entering the body Come and decide. Not all pesticide-contaminated food causes poisoning. If the contamination is mild and people eat a small amount, no obvious symptoms will appear, but they often have general symptoms such as headache, dizziness, weakness, nausea, and poor mental health. When pesticides are used, When the pollution is serious and a large amount of pesticides enter the body, obvious discomfort may occur, such as fatigue, vomiting, diarrhea, muscle tremors, palpitation, etc. In severe cases, symptoms such as systemic convulsions, coma, and heart failure may occur, and death may occur. The symptoms of poisoning also depend on the type of poison. The main types of poisoning caused by residual pesticides are: methamidophos, parathion (1605), methyl parathion, phorate, omethoate, carbofuran, etc.

Human odor pollution

There are more than 400 kinds of metabolites in the human body. There are 149 species excreted in exhalation, 229 species in urine, 196 species in feces, 151 species in sweat, 271 species excreted through the skin, etc. The emissions include carbon dioxide, carbon monoxide, hydrocarbons, acetone, benzene, methane, aldehydes, etc. In the case of air circulation, pollutants will diffuse quickly and there will be no smell. If there are many people in a room, car or boat cabin and the ventilation is poor, it will be full of "human flavor".

How to remove pesticide residues on vegetables

There are several simple ways to remove pesticide residues on vegetables and fruits at home:

Soaking and washing method: Vegetables The types of contaminated pesticides are mainly organophosphorus pesticides. Organophosphorus pesticides are difficult to dissolve in water. This method can only remove part of the contaminated pesticides. But washing is the basic method for removing other dirt and residual pesticides on fruits and vegetables. Mainly used for leafy vegetables, such as spinach, daylily, leek flowers, lettuce, Chinese cabbage, etc. Generally, rinse the surface dirt with water first, and then soak it in clean water for no less than 10 minutes. Fruit and vegetable cleaning agents can increase the dissolution of pesticides, so a small amount of fruit and vegetable cleaning agents can be added during soaking. After soaking, rinse with running water 2-3 times.

Peeling method: There are relatively large amounts of pesticides on the surface of vegetables and fruits, so peeling is a better method to remove residual pesticides. Can be used on apples, pears, kiwis, cucumbers, carrots, winter melons, pumpkins, zucchini, eggplants, radishes, etc. When handling, prevent peeled vegetables and fruits from being mixed and contaminated again.

Storage method: Pesticides can slowly decompose into substances harmless to the human body over time in the environment. Therefore, fruits and vegetables that are easy to preserve can be stored for a certain period of time with less pesticide residue. Suitable for apples, kiwis, winter melons and other non-perishable varieties. Generally stored for more than 15 days. It is also recommended not to eat freshly picked unpeeled fruits immediately.

Heating method: Carbamate pesticides decompose faster as the temperature increases. Therefore, some pesticides can be removed by heating some vegetables and fruits that are difficult to treat with other methods. Commonly used in celery, spinach, bok choy, cabbage, green peppers, cauliflower, beans, etc. First, wash the surface dirt with clean water, put it in boiling water for 2-5 minutes, remove it, and then rinse it with clean water 1-2 times.

What are minerals

Human beings are inseparable from minerals in all aspects of clothing, food, shelter, and transportation. For example, the various materials needed to build houses, the gemstones you wear, and the salt you eat every day all come from minerals. What are minerals?

Only substances that meet the following conditions can be called minerals:

1) Minerals are natural compounds or simple substances formed by various geological processes, such as volcanism. They can be solid (such as quartz, diamond), liquid (such as natural mercury), gaseous (such as water vapor in volcanic vents) or colloidal (such as opal).

2) Minerals have certain chemical compositions. For example, diamond is composed of elemental carbon (C) and quartz is silicon dioxide (SiO2). However, the natural mineral components are not completely pure and often contain a small amount of impurities.

3) Minerals also have a certain crystal structure, and their atoms are arranged regularly. For example, the crystal arrangement of quartz is that each of the four corners of silicon ions is connected to an oxygen ion to form a tetrahedron. These tetrahedrons are connected to each other at the corners to form a shelf-like structure in a three-dimensional space.

If there is sufficient growth space, solid minerals will have a certain form. For example, diamond is formed into an octahedral shape, and quartz is often formed into a columnar shape, with horizontal stripes often appearing on the cylinder surface. When there is no room for growth, their inherent form cannot be expressed.

4) Minerals have relatively stable physical properties. For example, galena is steel gray, has a very bright metallic luster, and is opaque. Its powder (striations) is black and soft (can be scratched with a knife).

Diamonds "fly" out of graphite powder

When it comes to diamonds, people will think of dazzling and dazzling scenes. It shines with the owner's activities. But because of its high price, most people can only stay away. Despite this, people still yearn for diamonds. Do you know what a diamond is? Its chemical composition is carbon (C). Natural diamonds are called "diamonds" only after they are polished. Natural diamonds are very rare. There are only 2 diamonds weighing more than 1000 carats (1 gram = 5 carats) in the world, and there are only many diamonds weighing more than 400 carats. The largest diamond discovered in my country so far weighs 158.786 carats, which is "Changlin Diamond". Things are rare and valuable. Because natural diamonds that can be used to make "diamonds" are very rare, people want to replace them with "artificial" diamonds. This naturally leads to the idea of ??diamond's "twin" brother - graphite.

The chemical composition of diamond and graphite is carbon (C), which is called "allotrope". From this name, we can know that they have the same "quality", but the "shape" or "nature" is different, and they are very different. Diamond is the hardest substance at present, while graphite is one of the softest substances.

The hardness of graphite and diamond is so different, but people still hope to use artificial synthesis methods to obtain diamond, because graphite (carbon) is very abundant in nature. But it is not so easy to change the carbon in graphite into a diamond-like arrangement. Graphite can be transformed into diamond at a pressure of 50,000 to 60,000 atmospheres ((5-6) × 103MPa) and a high temperature of 1000 to 2000 degrees Celsius, using metallic iron, cobalt, nickel, etc. as catalysts.

At present, more than a dozen countries in the world (including my country) have synthesized diamonds.

However, because the particles of this kind of diamond are very fine, it is mainly used as abrasives for cutting and drill bits for geology and petroleum drilling. Currently, 80% of the world's diamond consumption is mainly used in industry, and its output far exceeds the output of natural diamonds.

The initially synthesized diamond particles are black, 0.5mm in size, and weigh about 0.1 carat (diamonds used for gemstones generally have a minimum size of no less than 0.1 carat). At present, the large-grained diamonds developed in our country are more than 3mm, and the United States, Japan and others have made diamonds of more than 6.1 carats. We say that diamonds have "flyed" out of graphite, and gem-grade artificial diamonds will also be available on the market in the near future.

"World Water Day"

March 22, 1999 is the seventh "World Water Day" and the first day of the new "China Water Week". The National People's Congress The Committee of Agriculture, the Environmental Protection Committee and the Ministry of Water Resources jointly held a commemorative symposium in Beijing, calling on the whole society to pay more attention to my country's water resources issues. Water is an irreplaceable resource that humans rely on for survival and development, and has increasingly become a constraint on the sustainable development of the global economy and society. In order to arouse public attention around the world to water issues, the 47th United Nations General Assembly designated March 22 each year as "World Water Day" in 1993.

The theme of this year's "World Water Day" is "Everyone Lives Downstream", which aims to remind people to consider the interests of downstream residents when developing and utilizing water resources. As China draws more and more water from the Yellow River to meet the needs of its economic growth, the Yellow River began to struggle to meet water supply needs 25 years ago. In 1972, the water level of the Yellow River dropped significantly, causing the Yellow River to dry up before reaching the sea for the first time in China's long history. The Yellow River was dry for 15 days that year, and continued to dry up intermittently for the next 10 years. Since 1985, the Yellow River has been drying up every year, and the drying time is getting longer and longer. In 1996, the Yellow River stopped flowing for 133 days. In 1997, due to drought, the Yellow River stopped flowing for 226 days. This year, the river water failed to flow to Shandong Province, the last province where the Yellow River flows out to sea for a long time.

In addition, increasingly serious water pollution will also cause water shortage. When harmful substances in water exceed the self-purification capacity of the water body, pollution occurs. These harmful substances include toxic substances such as pesticides, heavy metals and their compounds, organic and inorganic chemicals, pathogenic microorganisms, oil substances, plant nutrients, various wastes and radioactive substances, etc. The main sources of water pollution are untreated industrial wastewater, domestic wastewater and hospital sewage.

Water pollution is extremely harmful to human health. Pathogenic microorganisms and viruses in sewage can cause the spread of infectious diseases. Toxic substances in water can poison humans and animals, and some highly toxic substances can kill organisms in the water and people who drink the water within a few minutes. This situation is relatively easy to detect. The most dangerous thing is pollution from metal compounds such as mercury, cadmium, chromium, and aluminum. They cause chronic poisoning after entering the human body and cannot be stopped once discovered. According to a survey by the World Health Organization (WHO), 70% of people in the world do not have access to safe and hygienic drinking water. Now 15 million children under the age of 5 die every year in the world, and most of the causes of death are related to drinking water. According to United Nations statistics, 25,000 people in the world get sick every day from drinking contaminated water or die due to lack of water.

The discovery of acid rain

The modern industrial revolution started with the steam engine. Boilers burned coal to generate steam to drive machines; then thermal power plants spread all over the place, and the amount of coal burned increased day by day. . Unfortunately, coal contains impurity sulfur, about one percent, and will emit acid gas SO2 during combustion. The high temperature generated by combustion can still cause some chemical changes in the combustion-supporting air. Oxygen and nitrogen will combine, and acid gas NOx will also be emitted. They are washed away and dissolved by rain and snow in high altitudes, and the rain becomes acid rain; these acidic gases become impurities such as sulfate, nitrate and ammonium ions in the rain. In 1872, British scientist Smith analyzed the composition of rainwater in Renton and found that it is acidic, and rural rainwater contains ammonium carbonate, which is not very acidic; suburban rainwater contains ammonium sulfate, which is slightly acidic; urban rainwater contains sulfuric acid or acidic sulfates. , acidic. So Smith first proposed the term "acid rain" in his book "Air and Rainfall: The Beginnings of Chemical Climatology"

Sanitary drinking water and chemistry

Growing on the stove Water that boils over time, and water that is boiled repeatedly in an electric water heater. Because this kind of water has been boiled for too long, it contains many non-volatile substances, such as calcium, magnesium and other heavy metals and nitrite.

Drinking this kind of water for a long time will interfere with people's gastrointestinal function, causing temporary diarrhea and bloating; toxic nitrites can also cause hypoxia in the body, and severe cases can lead to coma, convulsions, and even death

People drink it All tap water has been chlorinated and sterilized. Thirteen kinds of harmful substances can be separated from chlorine-treated water, among which halogenated hydrocarbons and chloroform are also carcinogenic and teratogenic. When the water temperature reaches 90°C, the content of halogenated hydrocarbons rises from 53 micrograms per kilogram to 177 micrograms, which is twice the national drinking water hygiene standard. Experts point out that drinking unboiled water increases the risk of bladder cancer and rectal cancer by 21% to 38%. When the water temperature reaches 100°C, these two harmful substances will be greatly reduced as the steam evaporates. If it continues to boil for 3 minutes, it is safe to drink.

Acid rain

Simply put, acid rain is acidic rain.

What is acid? Pure water is neutral and has no taste; lemonade and orange juice are sour, and vinegar is more sour. They are all weak acids; baking soda water is slightly astringent and alkaline. Caustic soda water is astringent and has a strong alkali taste. They are alkalis. Scientists found that the sourness is related to the concentration of hydrogen ions in the aqueous solution; the alkaline smell is related to the concentration of hydroxyl ions in the aqueous solution; then they established an indicator: the negative value of the logarithm of the hydrogen ion concentration, called pH value. Therefore, the pH value of pure water is 7; the greater the acidity, the lower the pH value; the greater the alkalinity, the higher the pH value. Unpolluted rain and snow is neutral, with a pH value close to 7; when it is saturated with carbon dioxide in the atmosphere, it is slightly acidic, with a pH value of 5.65. Rain that is polluted by acidic gases in the atmosphere and has a pH value of less than 5.65 is called acid rain; snow with a pH value of less than 5.65 is called acid snow; fog that diffuses at high altitude or on high mountains (such as Mount Emei) and has a pH value of less than 5.65 is called acid fog.

The modern industrial revolution started with steam engines. Boilers burned coal to generate steam to drive machines. Then thermal power plants spread all over the place, and the amount of coal burned increased day by day. Unfortunately, coal contains impurity sulfur, about one percent, and will emit acid gas SO2 during combustion. The high temperature generated by combustion can still cause some chemical changes in the combustion-supporting air. Oxygen and nitrogen will combine, and acid gas NOx will also be emitted. They are washed away and dissolved by rain and snow in high altitudes, and the rain becomes acid rain; these acidic gases become impurities such as sulfate, nitrate and ammonium ions in the rain. In 1872, British scientist Smith analyzed the composition of rainwater in Renton and found that it is acidic, and rural rainwater contains ammonium carbonate, which is not very acidic; suburban rainwater contains ammonium sulfate, which is slightly acidic; urban rainwater contains sulfuric acid or acidic sulfates. , acidic.

Life in a drop of water

A drop of water is crystal clear. To the naked eye, there is nothing inside. But put it under a microscope. Hey, it’s really something new! Look, there are things like glittering "watchbands", slender "pins", flat "discs", and even delicate "iron anchors"... It's dazzling. What is this? This is plankton. Plankton are short in stature, most are only a few thousandths to a few hundredths of a centimetre, and are invisible to the naked eye. They are not very good at swimming. Some of them cannot swim at all and just drift with the current. But don’t underestimate these little guys, they have very strong reproductive capabilities! If under the right environment, an individual plankton can fill up the entire water body in a few days if allowed to develop! Even if it is limited by various natural conditions, its number is still considerable, and they can be called a "big family" in the water. "Yes.

Phytoplankton cannot survive without sunlight, so they mostly live on the surface of water bodies with sufficient sunlight.

Although the individuals of phytoplankton are insignificant, they are the original producers of food in the water. Without them, the big life in the water may not be able to survive. Plankton is the main feed for fish and part of the food source for humans. The working people in my country's coastal areas have long used the currents to catch larger plankton such as krill, prawns, etc. However, due to various conditions, they have not yet been able to catch large quantities of them. In the future, through further research and practice, it is very promising to better understand the distribution patterns of plankton, continuously improve fishing techniques, and use plankton as a direct food source for humans.

Things are divided into two parts. Although plankton has great economic significance, not all plankton are beneficial. Some plankton are harmful to fish.

Blue-green algae, Anabaena algae, etc. multiply in large numbers in hot weather, causing water quality to deteriorate, seriously affecting the normal life of fish and other aquatic organisms, and even causing mass death of fish. From 1946 to 1947, toxic phytoplankton bloomed in the Gulf of Mexico, causing massive fish deaths. The seawater stinks, seriously hampering people's breathing. This phenomenon has also occurred to varying degrees along the coast of our country. In the autumn of 1972, a large amount of yellow-brown filth floated on the surface of the East China Sea with a stinky smell. Fishermen called it "stinky water". This was caused by the massive proliferation of Oscillator algae.

Utilizing the beneficial aspects of plankton, preventing the harmful aspects, and turning harm into benefit is an important measure to improve the productivity of water bodies.

Carbon monoxide

CO is inhaled through the respiratory tract. Inhaled CO enters the blood through the alveoli and immediately combines with hemoglobin to form carboxyhemoglobin, causing hypoxemia and tissue hypoxia. The central nervous system is most sensitive to hypoxia and is therefore affected first. Common symptoms include: mental disorder, aphasia, blindness, etc. The patient needs to be quickly moved away from the poisoning site to a ventilated place, loosen the collar, keep warm, and closely observe the state of consciousness. Timely and effective oxygen administration is the most important treatment principle for acute CO poisoning. Apply hyperbaric oxygen therapy to quickly correct tissue hypoxia.