The role of salt in the human body. The importance of salt in human life Salt in nature and everyday life

Platonova Polina

Salt is a vital element in the nutrition of any person; a lot of things in our body depend on it. From the point of view of chemistry, salts are a whole class of substances with certain chemical properties. We used to call salt a substance that has a salty taste! The purpose of the work is to study the history of salt and its use in the modern world.

Download:

Preview:

Municipal budgetary educational institution

city ​​of Kurgan

"Secondary school No. 48"

Salt in life

Completed by: Platonova

Polina Andreevna,

6th grade student B

Leaders: Baeva

Lilia Nikolaevna

Shchepetova

Olga Vladimirovna,

chemistry teacher

2013

Salt in life

Introduction ……………………………………………………………………………………………. ...................3

The History of Salt……………………………………………………………………3

The method of extracting salt in antiquity and now ………………………..........4

Sayings about salt …………………………………………………………..... 6

“Salt” customs …………………………………………………………………7

The use of salt …………………………………………………………..... 7

Useful Tips …………………………………………………………......9

My experiments ………………………………………………………………9

Conclusion …………………………………………………………………….10

Applications …………………………………………………………………….11

Literature ………………………………………………………………………… 13

Salt (Appendix 1) is a vital element in the nutrition of any person; a lot of things in our body depend on it. But its excess can lead to various diseases, as well as its deficiency.

From the point of view of chemistry, salts are a whole class of substances with certain chemical properties. We used to call salt a substance that has a salty taste!

Goal of the work:

• To study the history of salt and its use in the modern world.

From the goal come tasks :

• Find out where salt comes from;
• To understand why it used to be valued more than gold, but now it costs almost nothing;
• Check some properties of salt in a practical way.

Object of study- salt.

History of salt

The women roasted freshly skinned game over the fire, and the men, tired of hunting, ate this half-cooked meat, sprinkled with ashes, with coals stuck to it.

People who did not yet know salt, and they liked the ash, which gave the meat a pleasant, salty taste.

Centuries have passed. People have learned to plant seeds and harvest small crops. Rubbing grains between stones, they obtained flour and baked cakes on hot stones. To give them a pleasant taste, the cakes were sprinkled with ashes from specially collected plants.

The same taste, but even more pungent, was given to food by white powder, which women accidentally found on stones near the seashore or on the shores of salt lakes.

The meat, rubbed with white powder, was preserved for a long time, as well as dried on fire or in the smoke of a fire. Therefore, white powder was highly valued and they began to look for it. So salt entered the life of man.

Acquaintance with salt in different places could occur in different ways. Hunters, tracking down game, noticed how a wild deer or elk licked a transparent stone that looked like ice in the grass. But this ice did not melt either in the hands or in the sun. And when the hunters tried it with their tongue, imitating the animal, they felt an unusually pleasant and spicy taste. They broke off pieces of stone and carried it away with them. It was rock salt. The discovery of salt and the beginning of its use was an epoch of the same importance as man's acquaintance with agriculture. Almost simultaneously with the extraction of salt, people learned to collect grains, sow plots of land and collect the first crop. And although grains contain little table salt, not like the meat and blood of animals, agriculture continued to develop. Consequently, man found a way to satisfy salt hunger, which was not felt with a meat diet. Man learned how to extract salt. With the ashes of plants, which were originally sprinkled on cakes and meat, a person, in addition to useful salts, absorbed a much larger amount of harmful substances.

Chance or instinct led people to choose plants containing more salt - saline and growing near the coast or at salty springs. Aristotle and Pliny report the Umbrian custom of eating the ashes of saline plants as the first attempt to obtain a salt substitute. But with the transition to vegetable food this method could no longer satisfy the need for salt, and mankind learned to look for real salt.

Over time, man found more and more salt, but, on the other hand, he saw that neither trees nor grasses grow on salt-soaked soil, and that neither fish nor shells live in densely salty water. The abundance of salt destroyed life; and salt began to be considered unclean, cursed. Therefore, starting from the most ancient times, the attitude towards salt began to develop in two directions: “sacred” salt became a symbol of eternity, purity and constancy, “cursed” salt became a symbol of barrenness, impoverishment and evil. On the one hand, salt cleansed with its holiness, on the other hand, it defiled with its magical impurity.

Method of extracting salt in antiquity and now

Salt mining in antiquity

As soon as people got to know the taste of salt, they began to cherish it extremely. The areas where its deposits were found were quickly settled and became the property of some tribe. In exchange for salt, they acquired such items that were valued in the places of its production. Because of the places rich in salt, there was a constant struggle between nomadic tribes. From all sides people came for salt. It was exchanged with those who owned the deposits. It is very likely that prehistoric tribes settled where the most favorable conditions for existence were: a warm climate, fertile soil, sufficient moisture and salt.

There are many places on the prairies of North America where salt is now mined, but the ancient Indian tribes did not know how to get it and were content with ash or dried seaweed. These algae were pressed into a cake and dried. Pieces of such a pie served as seasoning for food.

In California and in what is now Oregon, salt has been extracted from ocean water and from salt springs since time immemorial. Now we know where ancient world salt was mined, and we see that the places of salt extraction were located very far from each other. There were also countries where there was no salt at all or where people had not yet learned how to extract it.

On the territory of the CIS, the following extraction methods are used to obtain table (edible) salt:
- mine method;
- lake way;
- basin method (sea salt);
- vacuum evaporator;

In addition to those listed, table salt is also obtained by freezing (Russia, Kempendyai), by evaporation in open shafts (western Ukraine), and by mining in quarries (Tajikistan). The distribution of these methods of salt extraction is limited, therefore, they are not considered further.

Mine method (rock salt).Mining salt is mined in Ukraine (Artemovskoe deposit) and Russian Federation(Sol-Iletskoye and Tyretskoye deposits). (Appendix 2) Associated mining of rock salt is carried out at some potash mines. Commercially available salt combines Ural 10KS and Ural 20KS are used for salt extraction. The drilling and blasting method is currently not used.

Lake salt. Deposits of lake salt are located in the Russian Federation (Lake Baskunchak, Lake Burla) (Appendix 3), in Turkmenistan (Lake Guvly), in the Republic of Kazakhstan (Lake Zhaksykylysh, Lake Inder, Lake Balkhash, a number of lakes in the Pavlodar region . and others), in Uzbekistan (Lake Karaumbet). Salt is being mined at the above lake deposits. In addition, in the republics of Central Asia there are a number of lake deposits suitable for salt extraction.

Basin method (sea salt).Basin salt is mined in a number of small salt mines in the south of Ukraine. These are the Genichesk salt mine, the Heroic, Salt and Saki salt mines. The listed salt fields are located on the Black Sea coast. Basin salt is also obtained in Tajikistan, at the Asht salt mine. Due to the growing demand for sea salt, pool salt production has been increasing recently.

Vacuum evaporation method (extra salt).The main producers of extra salt are Mozyr Vacuum Evaporator Plant (Belarus), Usolsky Vacuum Evaporator Plant (Russia) and Slavyansky Vacuum Evaporator Plant (Ukraine). In addition, "Extra" salt is also produced at the Crimean soda plant, at "Novomoskovsk chlorine" in the Tula region. and some others. The method is based on the dissolution of underground salt layers, chemical purification of brines and subsequent evaporation under vacuum. This method makes it possible to obtain salt of high purity, of the order of 99.5% -99.7% NaCl, but requires large amounts of energy for evaporation.

For the Kurgan region, which is deficient in iodine, the salt must be specially iodized!

Sayings about salt

"Salt" customs

The custom of greeting a guest with bread and salt has been known in Russia since ancient times. Bread expressed the wish for wealth and prosperity, and salt was considered a talisman that could protect a person from hostile forces. “Hospitality” is still called the cordiality and generosity shown during refreshments. According to an old tradition, an important guest is still greeted in Rus' with bread and salt: he must break off a piece of bread, salt it and eat it.This is a wish for good, an expression of hospitality.This ancient rite means that the guest has entered into friendly relations and is ready to eat “a pood of salt” together with those who meet them, ready to share all their troubles and worries.

There was not a single country and almost not a single nation where salt did not serve as a magical talisman against the "evil eye". Salt was worn sewn into the amulet, salt was thrown into the fire, salt was poured into milk, into water, thrown on the threshold of the house, on the heads of children. Today, the customs and signs associated with salt have long lost all meaning. Only among some tribes of Africa superstitions have been preserved in all their strength and are still practiced in earnest.

Salt application

People use salt very widely in everyday life, when preserving and salting food products: fish, meat, vegetables, mushrooms, etc. The fact is that salt has a unique property - it kills bacteria and microbes that cause rotting and spoilage of food. The production of canned meat and fish is based on the same property. Such products do not deteriorate for a very long time, they are stored for a long time and can be used for food even several weeks after their preparation.

Salt is also a commodity that is widely used in industry. It is the basis for the production of chemical products, on the basis of which many plastics, aluminum, paper, soap, and glass are produced. Salt is used in the processing of furs and leather, in the manufacture of salt batteries and all kinds of filters. IN chemical industry salt is used to produce soda, chlorine, hydrochloric acid.

Salt solutions in water freeze at a lower temperature than pure water. This is the basis for sprinkling salt on the roadway and sidewalks in the city when it is necessary to melt the caked snow or ice during ice.

IN agriculture table salt is used for fertilizer and livestock feed.

Table salt is also needed in transport: it is sprinkled on the floor of railway cars to protect goods (such as wet manganese ore and coke) from freezing.

Salt is also useful from a medical point of view. The mineral iodine is added to table salt, and iodized salt is obtained. It is used to prevent iodine deficiency in the body, which can lead to thyroid diseases. Recently, it has become customary to add another mineral substance to salt - fluorine (salt fluoridation). Its use is a good prevention of caries.

Many people like to take baths with salt. For baths, as a rule, sea salt is used. Such procedures well cleanse the skin and tone it. Sea salt has a good effect on the human nervous system.

It is known that during the Great Patriotic War surgeons working in field hospitals applied to the wounded on extensive lacerations cotton cloth soaked in a solution of common salt. Thus, they saved them from gangrene.

Often rock salt is used as a medicine. In the workings of salt mines, underground clinics and sanatoriums are created. They have constant temperature, humidity, pressure all year round, and most importantly, there are no microorganisms that cause allergic diseases, which include asthma. There is a high content of rock salt vapors in the air. Patients do not take medication. All procedures are kept to a minimum. The stay of the organism in sterile air, which has disinfecting properties, contributes to its strengthening, less predisposition to diseases. A month later, patients with bronchial asthma are cured of a hacking cough and asthma attacks. And all this happens thanks to the healing air of the salt mines. Underground sanatoriums for patients were opened in the salt mines of Wieliczka - Poland, Solotvyno - Transcarpathia, Kyrgyzstan, Nakhichevan Republic.

Helpful Hints

• How to determine the freshness of an egg? Add a teaspoon of salt to a cup of water. Put the egg into the solution. If it floats, it is better not to use it, but drowning in such water is most likely fresh.
• To easily peel boiled chicken eggs from the shell, add a little salt to the water in which they will be boiled.
• If you add a pinch of salt to a jug of fresh milk, it will keep longer.
• Iron marks can be removed by dampening them. cold water and sprinkle well with salt, after 20 minutes you need to shake off the salt and rinse the product.

• To remove a greasy stain on clothes, you must immediately sprinkle it with salt and wait for 10 minutes and then shake off the salt.
• Firewood sprinkled with salt flares up more easily and burns more evenly and longer.

My experiments

1. Salt dissolves in water

I took a jar of water, dipped a tablespoon in it and scooped up the salt with it. The salt stuck to the spoon. I thought: what will happen if you tilt the spoon vertically, does salt pour from it? Probably yes, because the salt is quite heavy. I started the experiment: part of the salt, the one that was at the very top of the spoon, really woke up in a jar. Adhering grains remained in place. Then I dipped the whole spoon in water - the salt disappeared from it.

Conclusion: Salt does not fall off a wet spoon, it dissolves. Salt will dissolve even if the spoon is not tilted at all - just pour water on it. Looking closer, I saw that the salt consists of small crystals. It turns out that salt is like ice - when it gets into water, it melts. (Annex 4)

2.Salt can preserve food

I put two tablespoons of salt and a cube of chocolate in a jar of water and left them on the windowsill until the next day. In the morning I pulled out a cube of chocolate. From the water it became soft, like plasticine, and from the salt it became salty, even inside, when I broke it open and tasted it.

Conclusion: chocolate does not dissolve in salt water, but it can “salt”. That is why, until recently, salting was the main way to preserve food. (Annex 5)

3. Crystal from salt (Appendix 6)

It is easy to grow a crystal from salt: you need to take a woolen thread, add enough salt to the water so that it no longer dissolves, and leave it for 2 weeks.

Conclusion

In the course of my research, I learned that the history of salt has more than one thousand years, that it was once a luxury item and wars started because of it.

I learned that before people did not know where it comes from, how to get it, they attributed it magical properties- that's why she was so expensive

I found out that in the modern world, salt is used not only in the food industry, but also in various other areas, has a wide range of applications.

Made sure that modern world does not attribute "magical" properties to salt, but needs it no less than our ancestors.

Conducted practical experiments and learned about some properties of salt.

Applications

Annex 1

Appendix 2. Iletsk deposit (mine method)

Annex 3. Lake Baskunchak (lake salt)

Appendix 4

Appendix 5

Appendix 6

References:

• Site materials "o-soli.ru"
• Materials of the site "fairy-tales.su.ru"
• Why. Children's encyclopedia. M., "Rosman", 2005

Agree, to meet a dog or a hamster who would refuse food because it is “unsalted” is simply impossible. With young children - the same story, they are not aware that food can be "salty and not salty." But adults, having used this preservative for thousands of years, have learned to distinguish shades of taste. Yes, people began to use salt precisely because it is an excellent preservative - it is a very dubious pleasure to prepare fish, meat, vegetables in "long-term storage" without salt. Salt increases their "shelf life" many times over. What the sailors greatly appreciated, eating bacon and lard on long trips, and peaceful peasants - juicy crispy pickles in the spring.

So what is salt for?

When a woman at the banquet table stretches her hand to the second pickle, the neighbors begin to chuckle knowingly, hinting at the possibility of an “interesting situation”. But a man who absorbs kilograms of roach, salty crackers and snacks on a glass of intoxicant with salted tomatoes never surprises anyone. Apparently, the ancestors make themselves felt - sailors and warriors, accustomed to eating salty. Only here on hikes, especially on foot, increased salt intake is justified, because with increased physical exertion, the sodium it needs is “washed out” of the body), but in the evening at home in front of the TV with beer and roach, all the salt is almost “deposited” in reserve in the body.

White (rarely grayish) salty-tasting powder, which we used to see daily on our table, is nothing more than sodium chloride (NaCl) - a substance involved in maintaining and regulating the water-salt balance in our body. The difference in the concentration of sodium inside and outside the cell is used for the entry of nutrients into it and the removal of waste products. Also, salt is necessary for the proper transmission of impulses between nerve cells. Salt is also involved in the production of hydrochloric acid, an important component of gastric juice. All in all, edible salt our body NEEDED, only the question is - in what quantity?

Since sodium is exclusively necessary for interstitial and intracellular metabolism, activation of digestive enzymes, regulation of acid-base balance, maintaining the level of water-salt balance in the body, and salt is its main supplier, it makes no sense to completely abandon it. Ideally daily salt requirement should not exceed 3 - 5 grams (the so-called "winter norm"), but with profuse sweating associated with the hot season or physical activity, you need to increase your salt intake to 10-15 grams.

When talking about salt intake rate, they consider not only the amount that we add to food during cooking or already on the table, but also take into account the content of this substance directly in the products. So, for example, half a liter of milk contains approximately 2 g of salt, 200 grams sauerkraut- 1.5 g of salt, in a typical serving of marine fish weighing approximately 150 g (perch, cod, etc.) - 0.2 g of salt. In general, if we take into account all the products that we eat in a day, then the “winter” norm (about 5 g) is obtained easily, and sometimes even with “more than”. Everything that enters the body beyond this is not good, but harmful. And it is expressed by an increase in blood pressure, headaches - all this, roughly speaking, is our body's protest against chronic "oversalting".

Let's think about what happens after you have eaten something salty, for example, herring or salted nuts? That's right - you really want to drink! Why is this happening? Yes, because excess salt in the body, he received an overabundance of such elements as sodium and chlorine (we all remember that the formula of table salt is NaCl) and now he wants only one thing - to get rid of them as soon as possible. And you drink - water, tea, beer, etc. Consequently, the kidneys and the cardiovascular system begin to work in overload mode. Moreover, no matter how hard they try, part of the salt, usually, is not excreted from the body. And with it - there is also excess water. As a result, we get edema, high blood pressure. Doctors say that using a large number of salt, we risk getting a whole bunch of diseases of the cardiovascular system.

Usually in men, problems with the cardiovascular system manifest themselves, first of all, in the form of hypertension - high blood pressure. Today, hypertension is very rejuvenated and cases of the disease are not uncommon in 20-25 year olds. Among doctors, the harmful effect on blood pressure is absolutely indisputable. excess salt in the body. Studies have found that excessive salt intake causes fluid retention in body tissues, increasing cardiac output, resulting in increased blood pressure levels.

An excess of salt threatens ... with cancer!

This conclusion was reached by Japanese scientists. They conducted a study in which they found that lovers of "salty" risk of developing stomach cancer is twice as high as those who do not abuse salt. Moreover, according to scientists, it was men who fell into the risk group. Women are stronger in this regard. Be that as it may, the Japanese made the only possible conclusion - the use of salt is good in moderation, and too much salt very harmful.

Sections: Chemistry

Lesson Objectives.

• Educational– create conditions for self-study chemical properties, meanings and uses of salts.
• Educational:
  • to promote the development of skills to analyze the content of educational material, to conduct a chemical experiment, the development of skills to compose ionic and redox equations of chemical reactions.
  • development of skills and abilities, work with a textbook and additional literature, rules for working on the desktop, the ability to systematize and generalize, establish cause-and-effect relationships, conclusively and competently express one's thoughts, draw conclusions.
• Educational- to promote the development of cognitive activity of students, the ability to formulate and express their thoughts, to reason logically.

Equipment and reagents. Laptop, projector, ready-made presentations, laboratory equipment: test tubes, glasses, pestles, mortars, dry fuel, matches; sensors: measurements of nitrates, acidity, water hardness; mini-laboratories with reagents: solutions of barium chloride, silver nitrate, sulfuric acid, iron (II) sulfate, sodium hydroxide, red blood salt, aluminum chloride, sodium carbonate, potassium chloride, ammonium carbonate, UIB; distilled water, tap water, well water, rainwater, soap solution; watermelon pulp, carrot juice, mineral water, Cola drink.

In advance, the class is divided into 4 groups: "Salts", "Nitrates", "Acidity", "Hardness". Students in each group identify a Theoretical Chemist, an Experimental Chemist and a Biologist. Each group independently prepares the theoretical and experimental part of the lesson, finds additional information from the add. literature and the Internet. Before the start of the lesson, the desks are placed together in two to form 4 islands. Briefing for practical work is printed in advance and distributed to groups.

DURING THE CLASSES

Opening remarks by the teacher of chemistry and biology

2013 has been declared the Year of the Environment. Clean air, clean water, clean food are the basis of a healthy life. Our health depends on the ecological situation in the region, country, in a particular house. In today's research lesson, we must consolidate the general chemical and specific properties, practical application and biological significance of salts. We will compare, analyze, apply information from other areas, we will develop communication skills and show the results of group work.

The performance of the group "Soli"

Chemist - theorist of "Salt". Salts play an important role in nature and in our life. Therefore, the goal of our group is: to give a general description of salts, to conduct experiments to determine salts and to reveal the significance of salts in nature and human life.

A theoretical chemist talks about the presentation of "Salt".

salt – substances consisting of metal atoms connected to an acidic residue.

General class formula: Me n A m

Physical properties of salts: salts, with a few exceptions, are solid crystalline substances of various colors. According to their solubility in water, they are divided into:

– soluble;
- slightly soluble;
- insoluble.

Chemical properties of salts:

Salts interact:

1) With simple substances - metals and non-metals.

2) With complex - acids, bases and salts.

3) With metals:

CuSO 4 + Fe \u003d FeSO 4 + Cu
copper(II) sulfate iron(II) sulfate

4) With non-metals:

2KI + Br 2 = 2KBr + I 2
potassium iodide potassium bromide

5) With acids:

2NaCl + H 2 SO 4 \u003d Na 2 SO 4 + 2HCl

6) With salts:

AgNO 3 + KCl \u003d AgCl + KNO 3

7) With alkalis:

FeCl 2 + 2NaOH \u003d Fe (OH) 2 + 2NaCl

Speech by the Experimental Chemist “Practical work No. 1. Salt detection" ( Annex 1).
Next comes the Biologist from the "Salts" group with a presentation on the meaning of salts.

Salt biologist. Rock salt deposits on planet Earth were formed as a result of the evaporation of sea water under the influence of solar radiation.

Food salt

• A simple seasoning for dishes.
• For home canning.
• In food production.
• By production of meat and fish canned food.
• For household needs.

Salt and human health

Not enough salt: drowsiness; weakness; dizziness; nausea; scurvy; loss of taste; damage to the nervous system; spasms of smooth muscles.
Lots of salt: load on the heart; ischemic disease; load on the vessels; swelling; hypertension; kidney problems; weight gain, obesity; metabolic disease.

• According to experts, sea salt much better than ordinary iodized.
• Sea salt contains almost the entire periodic table.
• Edible sea salt can buy in any supermarket.
• Her better add to ready meals, because the beneficial properties of sea salt are lost during heat treatment.
• She has one drawback - sea salt costs much more than ordinary table salt.

Speech by a theoretical chemist from the "Nitrates" group on the presentation of "Nitrates".

Theoretical chemist "Nitrates". Nitrates are solid crystalline substances, refractory, belong to strong electrolytes.
Historically established names of nitrate salts.
Potassium, sodium, calcium and ammonium nitrates are called saltpeters.
KNO 3 - potassium nitrate (Indian saltpeter), NaNO 3 - sodium nitrate (Chilean saltpeter), Ca (NO 3) 2 - calcium nitrate (Norwegian saltpeter),
NH 4 NO 3 - ammonium nitrate (ammonium or ammonium nitrate, there are no deposits in nature).
German industry is considered to be the first in the world to obtain salt NH 4 NO 3 from nitrogen N 2 of air and water hydrogen suitable for plant nutrition.

Chemical properties of nitrates

1. Interaction of nitrates with metals, acids, alkalis, salts

• Cu(NO 3) 2 + Zn = Zn(NO 3) 2 + Cu
• AgNO 3 + HCl \u003d AgCl + HNO 3
• Cu(NO 3) 2 + 2NaOH = 2NaNO 3 + Cu(OH) 2
• 2AgNO 3 + BaCl 2 \u003d 2AgCl + Ba (NO 3) 2

All nitrates are thermally unstable. When heated, they decompose to form oxygen. The nature of other reaction products depends on the position of the metal forming the nitrate in the electrochemical series of voltages.

Speech by the Experimental Chemist with practical work No. 2 ( Annex 2).
Further, the Experimental Chemist conducts experiments with a nitrate determination sensor, examines juices for nitrate content: watermelon, carrots; mineral, tap water, cola.
Speech by the Biologist on the topic “Nitrates. The harmful effects of nitrates on the human body.

Biologist "Nitrates". Everyone knows that the most precious thing a person has is his health, which cannot be bought and which largely depends on his health. proper nutrition. No wonder there is a proverb: “Tell me what you eat, and I will tell you what you are sick with!”
For most, it is no longer a secret that it is better to eat more fruits and vegetables for better health.
What are the main sources of dietary nitrates?
It's exclusive herbal products. In animal products, the content of nitrates is negligible. The maximum accumulation of nitrates occurs during fruit ripening. Therefore, unripe vegetables may contain more nitrates than those that have reached normal harvesting maturity. In addition, the content of nitrates in vegetables can increase dramatically if nitrogenous fertilizers are applied incorrectly.
The quality of vegetables depends on many factors, including fertilizers applied and plant protection products used. Nitrates are used as fertilizers and are known as saltpeters: sodium, potassium, ammonia and calcium. Nitrates are the most important component of plant nutrition, since the nitrogen included in them is the main building material of the cell.

It is now well known that nitrates are highly toxic to humans:

• Nitrates are especially dangerous for infants.
• Nitrates contribute to the development of pathogenic intestinal microflora, which releases toxic substances into the human body - toxins.
• Nitrates reduce the content of vitamins in food, and through them affect all types of metabolism.
• The amount of iodine decreases; a sharp expansion of blood vessels; pressure drop. Influence the occurrence of cancerous tumors in the gastrointestinal tract.

The main signs of nitrate poisoning:

• Blueness of the nails, face, lips and visible mucous membranes;
• Nausea, vomiting, abdominal pain;
• Enlargement of the liver, yellowness of the whites of the eyes;
• Headaches, increased fatigue, drowsiness, decreased performance;
• Shortness of breath, increased heartbeat, up to loss of consciousness;
• With severe poisoning - death.

Ways to reduce harm:

• The amount of nitrates decreases during the heat treatment of vegetables (washing, boiling, frying, stewing and blanching);
• Because there are more nitrates in the peel of vegetables and fruits, then they must be peeled, and for spicy herbs their stems must be thrown away and only leaves should be used;
• It is necessary to store vegetables and fruits in the refrigerator, because. at a temperature of + 2C, it is impossible to convert nitrates into more toxic substances - nitrites.

Theoretical chemist "Acidity". Do we know what to eat and what not to eat, what hygiene products and who can use them?

The goals of our work:

1. Study the literary sources on the named topic;
2. Obtain and examine indicators from natural raw materials;
3. Practically familiarize yourself with the methodology for determining the pH of the medium of liquids used by humans.

Can we measure pH at home?

Hydrogen indicator, pH(pronounced “pash”) is a measure of the concentration of hydrogen ions in a solution, quantifying its acidity.

– pH of acidic solutions< 7;
– pH of alkaline solutions > 7;
– The pH of neutral solutions is 7.

Preparation of indicators.

Plants (more precisely, their decoctions) can serve as the raw material for the preparation of indicators: many flowers, fruits, berries, leaves, and roots contain colored substances that can change their color in response to changes in the pH of the medium.
To provide yourself with indicators for the whole year, you need to dry the petals and berries in the summer, put them in separate boxes, then prepare decoctions from them, separately from each plant.
Decoctions of plants deteriorate quickly, so the indicators must be prepared before the experiment.
Take some stocked raw materials (the exact amount does not matter), put in a test tube, pour water, put in a water bath and heat until the solution is colored. After cooling, filter each solution and pour into a clean bottle prepared in advance with a label.

Speech by the Experimental Chemist with practical work No. 3 "Measuring the acidity of salt solutions" ( Annex 3).
Next, the experimental chemist conducts experiments to measure the acidity of the same salt solutions with a sensor for measuring acidity and draws conclusions.
Speech by the Biologist from the acidity group on the presentation "Acidity and its importance for living organisms."

Biologist "Acidity". Buffer properties of the cell.

buffering called the ability of a cell to maintain a slightly alkaline reaction of its contents at a stable level. The buffer properties of the cell are very important, since most biologically active substances (in particular, enzyme proteins) can only react at a strictly defined pH level.
Plants are indicators of soil acidity.
To determine the acidity, there are indicator plants. In the process of evolution, three groups of plants were formed: acidophiles - plants of acidic soils, neutrophils - inhabitants of neutral soils, basiphylls - grow on alkaline soils.

Speech by the Theoretical Chemist from the "Hardness" group on the presentation "Hardness of water and its definition".

Theoretical chemist "Rigidity". Water is one of the most common substances in nature. The hydrosphere covers 71% of the Earth's surface. Water plays an important role in the geological history of the planet. It is an essential component of almost all technological processes, both industrial and agricultural.
Living organisms cannot exist without water. About 65% of the human body is water
And what beauty she gave us! Waterfalls, geysers, oceans, seas, rivers - for all this we must thank the water. Rain, snow, hail - it's all water.
Why does water from different sources taste different, soap foams differently in it, and different scales settle on the walls of teapots?
Ca 2+ and Mg 2+ ions are constantly present in natural waters, which determine the overall hardness. The main source of their entry into the water is the dissolution of rocks containing limestone, dolomite, gypsum, and complex aluminosilicates. Hard water forms dense layers of scale on the inner walls of steam boilers and boilers, food products are poorly boiled in it, and more soap is consumed when washing clothes in hard water.
The total hardness of water is determined by the content of Ca 2+ and Mg 2+ ions in it. In the sum, the carbonate and non-carbonate hardness of water gives the total hardness.
Stiffness is temporary and permanent. Temporary hardness is determined in soluble form by the bicarbonates of the metals remaining in the water. When water is boiled, hydrocarbons decompose and precipitate. The growth of such precipitation on the walls of steam boilers and pipes inevitably leads to accidents. This is a serious reason for the need to eliminate water hardness.
Recently, many water softeners have appeared that protect washing machines from scale. At the same time, manufacturers of washing powders introduced anti-scale components into the composition of most washing preparations.
So, when buying washing powder, is it worth it to also buy a water softener for it? The answer is yes.
Many families use water filters. We decided to analyze the water passed through the filters. The results are provided in the table.

Conclusions.

1. In the course of our work, we found that waters from various sources differ significantly in the content of calcium and magnesium salts, so the hardness in the south is almost 2 times higher than in the north.
2. Modern washing powders contain components (polyphosphates) that reduce water hardness.
3. Household filters soften water quite well, reducing the content of calcium and magnesium by almost 2 times.

Next, the Experimental Chemist from the "Rigidity" group speaks with practical work No. 4 "Determination of rigidity and ways to reduce it" ( Appendix 4).
An experimental chemist from the "Hardness" group measures the hardness of distilled, tap, well and rain water with an electrical conductivity sensor and draws conclusions.
Next, the Biologist from the "Hardness" group speaks on the presentation "Hardness of water and its significance."

Biologist "Rigidity"

Can you drink hard water?
The human body requires living water, with its natural structure, physiologically complete in its composition. The main macroelements of water hardness are necessary for a person, so you can drink hard water, but in moderation.
The condition and functioning of the kidneys and the whole organism depends on the hardness of the water consumed daily by a person. Indeed, frequent consumption of hard water often leads to deposits of stones, as well as salts in the kidneys.

The impact of hard water on human health:

1) hard water, interacting with soap, forms “soap slags” that are not washed off with water and leave unsympathetic stains on dishes and plumbing surfaces; "soap slags" are also not washed off the surface of human skin, clogging pores and covering every hair on the body, which can cause rashes, irritation, itching;
2) there is a direct correlation between the hardness of drinking water and cardiovascular diseases;
3) when drinking hard water, there is a possibility of developing urolithiasis.

The final word of the teacher of chemistry and biology.

There are two main types of salt in the world, which are divided according to the method of extraction and quality - these are sea salt and table salt.

Salt

Let's talk about table salt first. Salt has always been more than just a seasoning in our lives. Once valued worth its weight in gold, it has firmly taken its place in proverbs, legends, superstitions and, of course, on our tables. Salt is the oldest seasoning for food, known to man, and almost no dish can be prepared without it. Its biological role is very important in human life. Salt is involved in maintaining and regulating the water-salt balance in the body, sodium-potassium ion exchange. Subtle biological mechanisms maintain a constant concentration of sodium chloride in the blood and other body fluids. The difference in salt concentration inside the cell and outside is the main mechanism for the supply of nutrients to the cell and the removal of its waste products. The same mechanism of salt concentration separation is used in the generation and transmission of nerve impulses by neurons. In addition, the chlorine ion in salt is the main material for the production of hydrochloric acid, an important component of gastric juice. The body makes up for the lack of salt by destroying bone and muscle tissue. Lack of salt can lead to depression, nervous and mental illness, digestive disorders and cardiovascular activity, smooth muscle spasms, osteoporosis, anorexia. With a chronic lack of salt ions, as well as other macronutrients, a fatal outcome is possible in the body.

Sea salt

Now let's talk about sea salt, which is more beneficial to humans than food salt. Sea water contains a large number of components necessary for the human body and maintaining its health: potassium, calcium, magnesium, iron, bromine, iodine, etc. These substances penetrate the skin and have a beneficial effect on the body.

One of the distinguishing features is the presence of iodine in sea salt. 5 grams of sea salt contains the body's daily need for iodine.

The complex of mineral components of sea salt:

potassium and sodium participate in the processes of cell metabolism.
Calcium takes part in the processes of formation of cell membranes. It plays an important role in wound healing and infection prevention.
Magnesium participates in metabolic processes and muscle relaxation, has an anti-allergic effect.
Bromine calms the nervous system.
Iodine regulates lipid and hormonal metabolism.
Manganese strengthens the immune system.
Zinc participates in the formation of immunity and maintaining the function of the sex glands.
Iron participates in the processes of oxygen transport and the formation of red blood cells.
Silicon improves skin elasticity and firmness and strengthens tissues.

Mostly sea salt is used in cosmetology. The use of sea salt as a therapeutic and prophylactic agent that improves skin condition is widespread. Sea salt is a unique healing agent that is used by SPA centers in balneotherapy programs, thanks to a complex of biologically active micro and macro elements. Baths with sea salt have a stimulating effect on the immune system, normalize sleep, restore skin structure, increase vitality. Taking baths with sea salt can significantly strengthen the immune system and nervous system. Sea salt does not dry the skin and has a positive tonic effect on the skin, promotes the correction of cellulite. Sea baths in combination with massage of problem areas will smooth the skin relief and eliminate the appearance of cellulite, making the skin soft and elastic.

These two salts are of great importance in our lives and they affect not only health, but also the beauty of a person.

Bibliography

• http://www.smartbuy.ru/
• http://www.doctorflora.ru/
• greenmama.ru

The value of salt in human life hard to overestimate. In the old days, it was not valued cheaply, signs are associated with it. Read about the real connection between salt and health.

This article is one of a cycle and the sixth in a series of articles united by the common title

Salt (sodium chloride) is a compound of sodium Na with chlorine Cl (NaCl). Life processes in the body are very connected with it. And this is justified. After all, life, as science suggests, originated in the ocean. It is not surprising that the composition of blood is close to sea water.

I must say right away that the amount of salt that is safe for the body, we can consume per day, is 5-6 grams. That's what nutrition experts say. Moreover, this amount includes salt, which is in the products that we eat during the day.

Now briefly about useful properties salt:

• contributes to the balance of water in the body;
• chlorine, which together with sodium forms salt, one of the main constituents of gastric juice;
• the nervous system is also functionally dependent on chlorine;
• fat metabolism also takes place with the participation of chlorine;
• the nervous system also functionally depends on sodium, which together with chlorine forms a salt;
• sodium promotes the transfer of oxygen in the blood;
• the beneficial properties of salt are used in salt caves for problems with the respiratory system;
• metabolic processes at the intercellular level cannot do without salt;
• salt solution can be used to eliminate swelling of the legs;

Now (also briefly) about the dangers of salt. I will note the importance of salt in human life can change not only with its excess, but also with a lack:

• Salt (due to sodium, Na) tends to retain water in the body. It is the manifestation of this property of salt that is dangerous when there is a lot of it in the body. It is dangerous that fluid retention leads to an increase in blood pressure;
• an increase in blood pressure increases the tension of the cardiovascular system and the heart. Additionally, both the kidneys and metabolic processes in the body are loaded;
• in the case of salt deficiency, the reverse phenomena are observed. Sodium in the body becomes low. This results in water loss. Together with it, macronutrients important for health, potassium, calcium, magnesium (K, Ca, Mg) leave the body.

The lack of each listed element can create serious problems. I wrote about the role of these and many other chemical elements for health in an article. I’ll add a little on what the three specified elements affect:

• potassium: necessary for violations in the work of large and small vessels, heart muscle, kidneys, liver, brain;
• calcium: necessary for all bone tissue and muscles, necessary for blood vessels and the nervous system;
• magnesium: needed immune and nervous systems, participates in digestion, the use of proteins, fats, enzymes;
• lack of salt also negatively affects the cardiovascular system.

On this article about salt and its importance in human life I will complete. I think the information has replenished your piggy bank of knowledge about the benefits and harms of salt. Put this knowledge into practice.