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 when hiking, 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, it is necessary to increase 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 about 2 g of salt, 200 grams of sauerkraut - 1.5 g of salt, in a typical serving of sea fish weighing about 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 eating a lot 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 levels is absolutely indisputable. excess salt in the body. Studies have found that excessive salt intake leads to fluid retention in the tissues of the body, increasing cardiac output, resulting in an increase in blood pressure.
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.
1.1. Importance of salt in human life.
We studied the issue of how valuable salt was to humans and concluded
: salt has always been of great importance in human life.
Without salt, a person cannot exist, and in order not to harm health, a moderate amount of salt should be eaten.
1.2. Salt in proverbs and sayings.
We also learned that the value of salt gave rise to a number of proverbs and sayings ( Annex A):
Without salt and bread, a thin conversation.
He will be born in water, but he is afraid of water.
They never eat me alone, and food is not tasty without me.
It is good for cereals, soup is not tasty without it.
One can live without gold, but one cannot live without salt.
To recognize a person, you need to eat a pound of salt with him.
You won’t be full of salt, you won’t get rid of tears of grief.
Bread - salt and good in a dream.
Bread - salt on the table, and dinner went.
Put salt to taste, but don't oversalt.
Without salt and bread - half a dinner.
1.3. Winged expressions and signs about salt.
(Annex B).
« ”- this is one of the wishes that Russian people exchanged with each other during a meal, emphasizing the value of salt equivalent to bread. So they say when meeting dear guests.
« Salt of the earth” implies the most important, most important, valuable.
« ” – they mean the very essence of the issue. 
Sprinkle salt - to a quarrel.
We decided that this sign arose a very long time ago. Indeed, in the past, salt was a very expensive commodity. And, of course, if someone spilled salt, they scolded him, a quarrel arose.
1.4. The use of salt in the home.
From various sources, we learned useful tips and recommendations on the use of salt in everyday life ( Annex B).
Glassware shines better if it is rinsed with salt water after washing.
Before lighting the candles, dip them in salt water - the candles will be less swollen, they will burn longer and more evenly.
Sections: Chemistry
Lesson Objectives.
- Educational- create conditions for independent study of the chemical properties, significance and use 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" ( Attachment 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 for a person is his health, which cannot be bought and which largely depends on his 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?
These are exclusively 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" ( Appendix 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 food seasoning known to man, and almost no dish is 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 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
RUSSIAN SCIENTIFIC CONFERENCE OF SCHOOLCHILDREN "OPENING"
SALT IN HUMAN LIFE
scientific research work in biology
Korotkova Darya Evgenievna,
pupils of grade 9b, secondary school No. 3
Rybinsk
Scientific adviser:
Sokolova Olga Nikolaevna,
chemistry and biology teacher
YAROSLAVL
Introduction…………………………………………………………………………….3
Relevance of the chosen topic, hypothesis, purpose of the work, tasks.
General characteristics of table salt.
Sodium chloride in nature and its extraction…………………………………………4
The structure of table salt………………………………………………………...5
The value of salt for a person in different historical periods……………….5
Sodium - potassium pump…………………………………………………………...6
Application of sodium chloride.
Main part.
Table salt in human life
2.2.3.1. In medicine……………………………………………………………………………..7
2.2.3.2. In everyday life………………………………………………………………………………..9
2.2.3.3. In industry……………………………………………………………………9
2.3. Practical part.
2.3.1. Determination of the content of table salt in foodstuffs
dishes………………………………………………………………………………..10
2.3.2. Drawing up a daily set of dishes, taking into account consumption norms
table salt……………………………………………………………………….11
3. Conclusion………………………………………………………………………….12
4. List of literature ...……………………………………………………………..13
1. Introduction
Among all the salts, the most important is
which we call salt.
A. E. Fersman.
They used to say “Salt is the head of everything, without salt and zhito is grass”, “One eye on the police (where is the bread), the other on the salt shaker (salt shaker)”, and also “Without bread it’s not satisfying, without salt it’s not sweet” ...
The Greek poet Homer (VIII century BC), who wrote the Iliad and the Odyssey, called table salt "divine". In those days, it was valued more than gold: after all, as the proverb said, “You can live without gold, but you can’t live without salt.” The value of table salt is great in our time. Remember the commotion last winter, when salt disappeared from store shelves, its cost increased several times.
The relevance of the work is as follows. In the 21st century, humanity is striving to learn new things, to look beyond the limits of the Universe and unravel the mysteries of the microworld. But sometimes, when solving global problems, it forgets about what is nearby, without which we cannot live and what we use every day. It is to such amazing substances that table salt belongs - known and familiar, unknown and mysterious.
Salt is essential for human life. It is involved in maintaining and regulating the water balance in the body. In cooking, table salt is used as the most important seasoning, it has a characteristic taste well known to everyone, without which food seems insipid. But excessive salt intake increases the risk of cardiovascular disease, can lead to high blood pressure and kidney disease.
Research hypothesis:
If you balance the use of table salt in food, then you can avoid cardiovascular diseases and thereby prolong the life of people.
Objective - to determine the dual nature of the value of table salt for a person (the unity of opposites).
Work tasks:
Study table salt as a chemical substance (structure, crystals, salt reserves).
Find out what effect salt has on the physiological processes occurring in the body.
Consider the areas of application of table salt (in everyday life, medicine, industry).
Conduct a study on the content of table salt in dishes used for meals at home and develop recommendations on the norms of salt intake in food.
2.Main part
2.1. General characteristics of table salt
2.1.1. Sodium chloride in nature and its extraction
The main part of table salt is sodium chloride. It is found in nature already in finished form. Salt is found everywhere in small quantities. But it is especially abundant in sea water and in salt lakes, in springs, in large masses it is found in the form of solid rock salt.
It is estimated that the sea water of all seas and oceans contains approximately 50 * 10 15 tons of various salts. This salt could cover the entire globe with a layer 45m thick. Salt accounts for most of 38 * 1015 tons. One liter of ocean water contains about 26-30 grams. table salt. In closed seas, where large rivers flow, salinity is lower (Black, Caspian), while in the Red, Mediterranean, and Persian seas, salinity is higher than the average oceanic, because. there is little rainfall and no inflow of fresh water, as well as significant evaporation.
Large amounts of salt are found in salt lakes. On the territory of our country, the Elton and Baskunchak lakes are especially rich in salt reserves. Salt reserves here are almost inexhaustible. Elton Lake covers an area of 205.44 km 2, and its bottom is covered with a layer of table salt more than 5 meters thick. Lake Baskunchak is located 53.5 km 2 from the Volga. It occupies a surface of 190 km, and at its bottom there are three layers of salt: the upper one, now being developed, is 6.5 and 9 meters, the middle one is 2 m and the lower one is over 13 m, and the salt reserve in only one upper layer is estimated at about 720,000,000 m 3 . The depth of the lake is not more than half a meter in winter and spring, while in summer this layer of water evaporates. This lake is located on top of a salt mountain, which goes down to a depth of more than a kilometer. This salt is 99% NaCl.
Solid or rock salt forms huge mountains underground, not inferior in size to the high peaks of the Pamirs and the Caucasus. The base of this mountain has a depth of 5-8
kilometers, and the peaks rise to the earth's surface and even protrude from it. Such gigantic mountains are called salt domes. At high pressures and temperatures, salt in the bowels of the earth becomes plastic. And since the coefficient of its thermal expansion is greater than that of other rocks, when heated, it expands and is squeezed upwards. In this case, the salt raises or pierces the rocks lying above it. Huge underground mountains of rock salt are located on the Caspian lowland, in the spurs of the Urals, in the mountains of Central Asia. Tajikistan has the highest salt domes, one of which rises to a height of 900 meters. Rich deposits of rock salt are located in Germany and Poland.
According to the method of extraction, salt is divided into several types:
Stone. It is extracted by mining, using underground mining, but it is possible to dissolve this salt and then pump out the solution. The solution is subjected to digestion. This salt is called boiled salt.
Self-planting salt or lake salt is extracted from the layers at the bottom of salt lakes.
Garden salt is obtained by evaporating or freezing estuaries and lakes from the water.
Evaporated salt is obtained by evaporation from groundwater.
Conclusion: Salt is a common substance on our planet that does not require large expenditures for extraction.
2.1.2. The structure of table salt
Sodium chloride is an ionic compound: it consists of sodium and chloride ions. In salt, these ions are ordered. They are attracted to each other due to the forces of electrostatic attraction, between existing oppositely charged ions.
Na f f f - 1e - Na f f
11 2 8 1 _ +11 2 8 -
Cl f f f - +1e - Cl f f f
17 2 8 7 +11 2 8 8
The attractive forces are significant, therefore, in order to set the ions in motion, i.e. to melt, t = 800 0 C is required, and the boiling point is 1413 0 C.
If a crystal of table salt enters the water, it quickly dissolves. Sodium and chloride ions are easily separated from each other. In this they are helped by water molecules that carry positive and negative charges on their surface. They are called dipoles. The water dipoles are oriented near the Na and Cl ions on the surface of the crystals with their charges and destroy the ionic bonds in the crystal. Na and Cl ions go into solution, surrounded by water dipoles, i.e. become hydrated ions.
Na and Cl ions can be released from water molecules only in the process
crystallization, but even then it is difficult. Everyone notices that if you throw salt crystals into a hot pan, they crack and burst. It is the water boiling up in them (it forms cavities in the crystals) that breaks the crystals. It is possible to prove that the composition of sodium chloride includes sodium and chloride ions using experiments: +
A. Na ions color the flame yellow.
B. Cl ions form with silver ions Ag (p - ra nitrate AgNO) white
curd powder.
Conclusion: Sodium chloride has an ionic structure: it consists of Na + and Cl - ions, which are attracted to each other due to the forces of electrostatic attraction.
2.2. Table salt in human life
2.2.1. The value of salt for humans in different historical periods
If we turn to history, we can see how valuable this substance was for a person.
Sodium chloride is an essential component of human food. It was equal in price to gold. In ancient Rome, legionnaires were often paid salaries not with money, but with salt, hence the word soldier.
Once upon a time in Holland there was a painful execution. The doomed received only bread and water, and they were completely deprived of salt. After a while, these people died, and their corpses began to decompose instantly.
In Kievan Rus, they used salt from the Carpathian region, from salt lakes and estuaries on the Black and Azov Seas. Here it was bought and taken to the North. It was so expensive that at solemn feasts it was served on the tables of noble guests, while the rest dispersed “not salty slurping”. After the accession of the Astrakhan Territory to the Moscow state, the lakes of the Caspian region became important sources of salt. She was simply raked from the bottom of the lakes and carried on ships up the Volga. And still it was not enough and it was expensive. For this reason, discontent of the lower strata of the population arose, which developed into an uprising known as the Salt Riot (1648)
In 1711, Peter I issued a decree on the introduction of a salt monopoly. Salt trade became the exclusive right of the state. The salt monopoly lasted another 150 years and was abolished in 1862.
In tsarist Russia, despite the rich deposits of salt, due to the primitive method of extraction and transportation, there was not enough salt. For many centuries it has been a source of enrichment for merchants and entrepreneurs. Salt has always been treated with respect and sparingly. Hence the popular sign - he sprinkled salt to a quarrel.
At the end of the 18th and beginning of the 19th centuries in Africa, where some areas are poor in salt, the English doctor and traveler Mungo Park saw negro children who licked pieces of rock salt with pleasure. And he himself said about this: “The constant use of plant foods excites a painful longing for salt to such an extent that it cannot be described properly.”
Conclusion: Since ancient times, people knew about the properties of table salt and used it for food.
Sodium-potassium pump
Sodium chloride is essential for the body. According to the studies of Academician Pokrovsky, the optimal dose of table salt is 10-15 grams per day. Consider the value of table salt at the cellular level. Cell walls are a semi-permeable membrane that separates solutions of different concentrations: the contents of the cell and the intercellular substance. Membranes are complex biological structures made up of proteins and fat-like substances. They let nutrients into the cell and excrete waste products.
The membranes are in constant motion, pulsing and renewing. The process of exchange between the cell and the intercellular substance is based on the phenomenon of osmosis. The membrane equalizes the concentration of substances on both sides. And since particles of a solute can be ions, they also carry electric charges. In this regard, diffusion through the membrane depends not only on the concentration difference, but also on the potential difference. Chlorine ions Cl - pass more easily into a less concentrated solution, and their presence creates a negative charge. Sodium ions diffuse weaker, because. have a thick hydration shell and they create a positive charge in places of accumulation. This creates a potential difference.
That's why we salt our food to supply the body with positive and negative ions. Chlorine ions are necessary for the formation of hydrochloric acid, which is part of the gastric juice and is involved in the digestion process.
In living organisms, the content of potassium ions K + is significant - the potassium element accounts for 140 grams in the human body, and 100 g for sodium. Potassium ions K + and sodium Na + take their places inside the body. There are much more potassium ions inside the cells (for example, there is 15 times more potassium in red blood cells than sodium, and 20 times less in blood plasma), so the blood is salty. Sodium ions, having a thick hydrated shell, are more difficult to pass through the cell membrane. The different content of K + and Na + in the cell and in the intercellular space creates a potential difference, promotes the movement of charged particles through cell membranes. There is a so-called potassium - sodium pump, which promotes the transfer of ions. The energy for this process is provided by adesintriphosphoric acid (ATP for short). The process of transition of various substances through cell membranes is very fast and the process of osmosis of the potential difference cannot provide such a speed.
It has been found that there are substances capable of transporting ions across cell membranes. The first such substance was discovered in 1955 by the German researchers Brockmann and Schmidt-Kastner, and in 1964 the American scientist Pressman found that this substance has the ability to form complexes with alkali metal ions and increase their ability to pass through membranes. Alkali metal carriers are called ionophores. The first ionophore was valinomycin. Further, other ionophores were obtained. They have a protein structure. They have a high biological structure. Thanks to them, the process of passage through the cell membrane of ions and molecules proceeds very quickly.
For research work in the field of ion transport through membranes, our scientists Yu. A. Ovchinnikov and V. T. Ivanov were awarded the Lenin Prize in 1978. Also, these substances are used as medicines, for example, valinomycin, gramicidin, antamanid.
The sodium-potassium pump underlies the transmission of nerve impulses. The transmission of nerve irritation occurs due to nerve cells - neurons. The long process of a nerve cell is called an axon and serves as a conductor of signals for the organ to which it connects. The axon is like a tube that contains liquid, and it is itself immersed in liquid. Both of these liquids contain dissolved salts and therefore conduct electricity well.
The fluid surrounding the axon contains Na + and Cl - ions. In the fluid inside the axon, there are K + cations and anions of organic origin. This design of the conductor is inferior to the metal one, but for living organisms it is quite sufficient. The nerve cell is at rest, inside it there is a negative charge - the resting potential. As soon as the nerve cell receives an excitation signal, the membrane conductivity for potassium and sodium increases dramatically. The cell potential drops to 0 and then rises to a positive value of +50 mV. The change in potential is due to the fact that sodium ions enter the cell, and potassium ions go outside. A change in their concentrations causes a change in potential. This is the meaning of nerve impulse transmission. These impulses govern our actions.
Na + and K + are of great importance in brain activity. Our memory is of two types: long-term and short-term. According to the currently existing hypothesis, the mechanism of short-term memory has an ionic nature. Ionic bonds are fragile, they can quickly break down - that's why memory is short. Long-term memory is associated with the formation of stronger structures.
Conclusion: Salt is vital for a person, it is involved in maintaining and regulating the water balance in the body, ion transport through cell membranes, and is involved in the mechanism of formation of short-term memory.
2.2.3. Application of sodium chloride
2.2.3.1. In medicine
Fluoride salt.
Iodized edible salt is table salt, which contains the mineral substance iodine. Recently, it is customary to add another mineral substance to such salt - fluorine, or rather potassium fluoride. The ratio of this additive and salt is about 250 mg per kilogram. For adults, effective caries prevention can be achieved with an additional intake of one milligram of fluoride per day. Usually, our food contains only 0.5-0.7 mg. Therefore, the consumption of fluoridated salt is essential.
However, in this regard, caution should be exercised in relation to young children who are already taking fluoride in the form of tablets as prescribed by a doctor: in excess, fluoride can be toxic to the body.
dietary salt.
It is a substitute for table salt, in which another element is presented instead of sodium, most often potassium. However, potassium chloride differs in taste from sodium chloride, and most often its taste is considered unpleasant. Therefore, in the consumer market (primarily in pharmacies and stores selling organic products), varieties of dietary salt containing both sodium chloride and other compounds are offered. It should also be borne in mind that potassium chloride can not always serve as an alternative to regular table salt. So, in case of disorders associated with a disproportion in the content of potassium in the body, for example, in acute renal failure, dietary salt can be eaten only after consulting a doctor.
Salt intake.
Doctors are unhappy with the excessive consumption of table salt and claim that this leads to an increased likelihood of diseases such as hypertension, atherosclerosis and strokes. Not without reason, at a symposium held a few years ago in Frankfurt am Main in Germany, doctors carried out a kind of trial of the "white death" and the "secret killer", as ordinary salt is called.
The average European consumes 15g. salt, and the Japanese even all 60! And Japanese doctors register the highest percentage of cases of hypertension in the world - this plague of the 21st century. Moreover, the American professor L. Page, examining blood pressure among the inhabitants of the tribes of Africa, Southern Iran, Greenland, Polynesia and Australia, found that almost all of the examined consumed small doses of salt. And Page did not record a single case of hypertension there, even in the elderly.
Today, many experts assume that the increase in blood pressure as a result of the consumption of table salt is due not so much to the presence of sodium in it, as previously stated, but to chloride. There is even debate about whether the chloride anion is the only culprit. Research results confirm that in other compounds, such as sodium bicarbonate (NaHCO3), found in many mineral waters, sodium does not have any pressure-increasing effect.
A group of researchers from around the world, who studied the relationship between table salt and hypertension (as part of the Intersalt project) on the example of 10,079 people in 52 cities in 32 countries, came to the conclusion, with certain reservations, that there is no simple direct relationship between salt intake and this disease. . More significant risk factors for this serious disease are being overweight, elevated blood fat levels, alcohol abuse, smoking, and stress. The most important conclusion is that only about 50% of all hypertensive patients react to salt, i.e. they are salt-tolerant. This means that blood pressure readings in these patients change markedly when salt intake is increased or decreased. This salt sensitivity is probably hereditary. It is more pronounced with excess weight and is more common in older people. Susceptibility to salt occurs - without any special manifestations - and in people who are considered practically healthy in relation to blood pressure. Salt abuse for many years can provoke hypertension in them. The relationship between excessive consumption of table salt and the development of hypertension was derived primarily from the fact that in most patients suffering from this disease, after taking a large amount of salt with food, a marked increase in blood pressure was observed. After a salt-free diet or therapy with the use of special medications that promote increased excretion of salts from the body (saluretic agents), these indicators decreased significantly. Scientists have come to similar results in experiments conducted with animals. In addition, among the representatives of primitive tribes in a number of regions of our planet, in whose food there is little salt, in fact, it was not possible to detect a single case of hypertension. They also do not experience an age-related increase in blood pressure, as is the case among the population of industrialized countries, who willingly consume salt.
Salt rubdowns or bathing in salt water - sea, lake are useful. For a long time, people came to the Turkmen lake Molla-Kara to be treated for diseases of the nerves and joints. The water of the lake is one and a half times saltier than the water of the Dead Sea. It serves as a reliable medicine to this day - people come here from all over the country! And the salty water of the underground lake is supplied to the baths of the Moscow balneary. Snow-white crystals are also necessary for obtaining a number of medicines: calomels, sublimes. Without it, you cannot prepare pyramidon tablets - a cure for headaches. Sometimes salt helps recovery, although it does not heal itself. In hot countries or hot workshops, where workers lose a lot of salt with sweat, it is advised not to drink water, but a weak solution of table salt. Salt mines are also equipped with facilities for the treatment of asthma patients.
Sodium chloride is used to obtain saline. Saline is a 0.85% NaCl solution in water. How much sodium chloride is found in human blood. In diseases, as a result of which the body loses a large amount of water, a saline solution is poured into a person.
Conclusion: Table salt is necessary for the human body, but its consumption in large quantities can lead to hypertension.
2.2.3.2. At home
It’s scary to think what would happen if people didn’t discover the beneficial property of salt - to save
decay products? But who was the first to discover the beneficial property of salt to preserve food? Moreover, to give them a special attractive taste? You can go around the whole world - you will not know. Only in Holland will the name of the discoverer be named.
From time immemorial people have been catching and salting herring here. She was fed, she was sold to other countries. According to legend, a thousand years ago, the method of salting herring was discovered by the fisherman Bekkel from the small seaside village of Bulikta. Here, as a “benefactor of the state”, a monument was erected to him.
What properties of salt are used in food preservation? Preservation by salting of various food products: meat, fish, vegetables, mushrooms, etc. - is based on the so-called antiseptic or anti-putrefactive properties of table salt, that is, on the ability to kill bacteria or microbes that cause decay of substances of plant or animal origin. The production of canned meat and fish is based on this property.
If such additives make up more than 15%, then such a salt can be named with the mention of this additive. As an example, we will give celery salt (a mixture of ground celery seeds with table salt), garlic salt. Some types of salt are usually labeled according to their purpose (smoking salt, salt for grilling, etc.).
Conclusion: Table salt has the ability to kill bacteria and germs, and thus save food from rotting.
2.2.3.3. In industry
Table salt is necessary in the metallurgical industry, in the processing of furs, rawhide, in the preparation of soap, in the production of soda ash. But the main consumer of salt is the chemical industry. It uses not only salt itself, but both elements that make it up. Salt is decomposed by electrolysis of its aqueous solution. At the same time, chlorine, hydrogen and caustic soda are simultaneously obtained. From a solution of caustic soda, after evaporation, a solid alkali is obtained - caustic.
Conclusion: Table salt is widely used in industry both for the production of other chemicals and as an auxiliary substance.
2.3 Practical part
2.3.1 Determination of the salt content in foods used in meals
The purpose of the study is to determine the actual level of consumption of table salt by an ordinary Russian family and develop recommendations in the form of a daily set of dishes in compliance with the norms for the consumption of table salt.
Preparation of solutions of salt (sodium chloride) of different concentrations. Using the chemical formula for calculating the mass fraction of a substance in a solution, calculations were made and solutions of sodium chloride with different concentrations (mass fractions) were prepared.
m (NaCI) + m (H 2 O)
Table 1. Conditions for the preparation of common salt solutions
Mass of salt | Water volume | Solution weight | Mass fraction of salt |
|
The resulting solutions were compared in taste with different home-cooked dishes (for the purity of the results, three people took part in the tasting - me and my parents), the results were entered in Table 2. Further, based on simple calculations, the content of table salt in a portion of different dishes was determined.
Table 2. Salt content in a certain mass of a dish (one serving)
Mass fraction of salt | |||
Stewed white beans, rice, buckwheat, black bread | For 200 g of beans, rice, buckwheat - 2 g of salt; For 250 g of bread - 2.5-3 g of salt |
||
Potato soup, pasta, milk porridge (scrambled eggs), boiled potatoes | For 250 g of soup - 5 g of salt; For 100 g of pasta - 2 g of salt (cook); For 200 g of porridge - 1.5 g of salt For 100 g of potatoes - 1.5 g of salt |
||
Broth with dumplings, sauerkraut soup, meat cutlets (sausage) | For 200 g of broth and cabbage soup - 6 g of salt For 1 cutlet weighing 50 g - 2 g of salt |
||
Medium salted herring | For herring weighing 25 g - 2 g of salt |
||
Cucumber pickle | For 100 g of brine - 12 g of salt |
||
pickled tomatoes | For 25 g of tomato - 4 g of salt |
To compare the results obtained, I present data on the content of table salt in dietary dishes. They show a tendency to reduce the mass of salt, which is explained by the purpose of cooked dishes for people with health problems.
table 3
Mass of salt |
|||
Potato soup | |||
Shchi from sour cabbage | |||
Bouillon with dumplings | |||
meat cutlets | |||
Milk porridge | |||
Boiled potatoes |
2.3.2. Drawing up a daily set of dishes, taking into account the norms of consumption of table salt.
A person who does not have chronic diseases is recommended to consume 10-15 g of table salt per day. I propose the following combination of dishes, taking into account the given norm of salt intake and the results obtained in the study.
Table 4. The combination of home-cooked meals containing the required norm of table salt.
First day | Second day | Third day |
Milk porridge - 1.5 g of salt Potato soup - 5 g salt Pasta - 2 g salt Cutlet - 2 g salt Bread - 1 g salt | Fried eggs - 1.5 salt Sour cabbage soup - 6 g salt Buckwheat - 2 g salt Beans - 2 g salt Sausage - 2 g salt Bread - 1 g salt | Milk porridge - 1.5 g Broth with dumplings - 6 g of salt Rice - 2 g salt Boiled potatoes - 1.5 g salt Sausage - 2 g salt Pickled tomatoes - 1 g salt Bread - 1 g salt |
14.5 g salt |
The above combination does not contain dishes (products) in the preparation of which a very small amount of salt is used or not used at all, such as cottage cheese and products made from it, all kinds of drinks and desserts, pastries, fruits, vegetables (salads from them). To compile a real daily (weekly) menu, we must not forget about these foods and dishes. Also, the considered combination of dishes, as a result, has the upper limit of the salt intake and is recommended for people who do not have a predisposition to diseases associated with the use of table salt.
Conclusion: From the results of the study, it follows that our family consumes table salt within the established norm, and I even slightly less than it.
3. Conclusion
The world's salt reserves are practically inexhaustible. A person uses for himself those sources that allow him, based on the conditions and habitats, to get more accessible, cheap, pure salt. The value of salt is great both in industry (for obtaining other substances) and directly for humans. It is extremely important for our body to maintain the constancy of the composition of the internal environment - homeostasis. This is the promise that all metabolic processes and any biochemical reaction will proceed normally, this is health. And these processes are greatly influenced by Na + and Cl - ions. Therefore, sodium chloride is salt No. 1 at all times as long as man exists.
Based on the results of the research work, the following can be done: conclusions:
Table salt is a substance necessary for the human body, which takes part in the metabolism. Salt is vital for maintaining and regulating the water balance in the body.
Uncontrolled salt intake can lead to cardiovascular disease, high blood pressure, and kidney disease.
Thus, we see that table salt has a dual character. On the one hand, it is necessary for the human body, and on the other hand, it is harmful to it.
Recently, the number of salty and spicy dishes in people's food has increased, which in large quantities is harmful to health. It is necessary to adhere to the recommendations given in this work in the form of a daily set of dishes, taking into account the norms of consumption of table salt. If you have to decide for yourself the question: to salt or not to salt, and the answer is positive, then do not forget about the golden mean.
The work carried out and its results are especially relevant today, when the national project "Health" is being implemented in our country. The increase in mortality is caused, first of all, by cardiovascular diseases, which is why control over the use of table salt is necessary for every person and every family.
Let's be healthy!
4. References
Zverev V.L. Stone rainbow. M.: Nedra, 1990 - p.23.
Kritsman V.A. A book for reading on inorganic chemistry, part 1. M .: Enlightenment, 1974 - p.336.
Leenson A.I. Entertaining chemistry part 1. M.: Bustard, 1996 - p.173.
Leenson A.I. Entertaining essays on chemistry. M.: Chemistry, 1988 - p.81.
Menshikov F.K. Medical nutrition. M.: Medicine, 1985.
Terletsky E.D. Metals that are always with you. M.: Knowledge, 1986 - p.142.
Chemistry at school N1 1975. M .: Pedagogy, - p.97.
Develop skills when weighing on laboratory scales, when measuring volumes of liquids, with chemical glassware, with chemical equipment, etc.
The work program of the course "healthy lifestyle" on extracurricular activities in the 1st grade of the teacher-organizer of obzh
Working program of the courseRelevance: The latest statistics show that during the period of schooling children's health deteriorates by 4-5 times. Therefore, the problems of maintaining the health of schoolchildren and inculcating healthy lifestyle skills in them
The circle program for the formation of a healthy lifestyle in children "zdravushka" 1 (for students of secondary school age) explanatory note
ProgramThe formation of a healthy lifestyle culture is one of the strategic goals of teaching and educating modern schoolchildren and youth. The culture of a healthy lifestyle of a person is his psychological (system of motives, valeological
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