What substances dissolve in water. Highly dispersed systems (true solutions) Substances that dissolve in water
Water is a liquid substance that has no taste, color or smell. Pure water is absolutely transparent. If you pour water into a glass glass, you can see objects behind it through its walls. Water has fluidity, thanks to which it penetrates through cracks and crevices and permeates everything around.
In liquid state, water:
- fills seas, oceans, rivers and lakes;
- saturates the soil;
- part of plants;
- is part of the bodies of mammals.
The amazing property of water is that it knows how to dissolve almost everything around. There are some objects that get wet but remain undissolved. How and why does this happen?
What is a solution?
When a substance dissolves, it mixes with a liquid to form a solution. A solution can be called tea in a glass, where the sugar cube was placed before. Water that has absorbed sugar tastes sweet. When a substance combines with a solvent, a solution is formed. An aqueous solution is a water-soluble substance that has been diluted with pure water. Water is a good solvent, but it cannot dissolve stone, wood, or plastic. If you throw several pebbles into water, they will remain at the bottom of the glass.
How does this happen?
If we examine a drop of water under a microscope, we will see that it consists of special particles called molecules. They cannot be seen with the naked eye. Water molecules are electrically neutral, this means that they are “friendly” with all substances. They have a special attraction to certain substances. The amazing friendliness of water molecules allows them easily combine with molecules of other substances, carrying a charge.
When it comes into contact with the molecules of another substance, the attraction intensifies, as a result the substance mixes with water, completely dissolving in it. If there is no attraction, then, accordingly, everything remains unchanged. The substance will remain at the bottom of the glass. If you add a little salt to the water and stir it with a spoon, the salt will soon disappear. The water will taste salty.
What is clean water?
Absolutely pure water does not exist in nature. Almost all liquids that we see in everyday life are solutions. Tap water is a solution of water with iron impurities. Before entering the glass, water flows through iron pipes, absorbing iron molecules. Natural solutions are drinks - tea, juice and compotes. All of them contain components beneficial to the human body. Water can dissolve not only solids, but also liquid and gaseous substances.
There is always something dissolved in ordinary water. Rain, water, river or lake water contains any impurities.
Which substances dissolve in water and which do not?
In nature there are solid, liquid and gaseous substances endowed with various properties. Some of them are able to dissolve in water, others are not. Depending on this feature, the following groups of substances are distinguished:
- water-repellent (hydrophobic);
- attracting water (hydrophilic).
Hydrophobic substances are either poorly soluble in water or do not dissolve in it at all. Such substances include rubber, fat, glass, sand, etc. Some salts, alkalis and acids can be called hydrophilic substances.
Since the cells of the human body contain a membrane containing fatty components, the fat does not allow the human body to dissolve in water. Due to the unique structure of a living organism, water not only does not absorb body cells, but supports human life.
Let's sum it up
When water comes into contact with food, it dissolves nutrients and then releases them to the cells of the human body. In return, the water picks up waste products, which are released through sweat and urine.
There are few substances in nature that are not soluble in water. Even metal, upon prolonged contact with water, begins to dissolve in it.
Water with components dissolved in it acquires new qualities. For example, a silver solution can kill microbes. Water is a system that can be beneficial or harmful to humans. And this depends on what is dissolved in it.
If this message was useful to you, I would be glad to see you
In an ordinary non-associated liquid, such as gasoline, the molecules slide freely around one another. In water, they roll rather than glide. Water molecules are known to be connected to each other by hydrogen bonds, so before any displacement occurs, at least one of these bonds must be broken. This feature determines the viscosity of water.
The dielectric constant of water is its ability to neutralize the attraction that exists between electric charges. The dissolution of solids in water is a complex process that is determined by the interaction of solute particles and water particles.
When studying the structure of substances using X-rays, it was found that most solids have a crystalline structure, that is, the particles of the substance are located in space in a certain order. Particles of some substances are located as if they were in the corners of a tiny cube, particles of others - in the corners, center and middle of the sides of a tetrahedron, prism, pyramid, etc. Each of these forms is the smallest cell of larger crystals of a similar shape. Some substances have molecules at the nodes of their crystal lattice (most organic compounds), others (for example, inorganic salts) have ions, i.e. particles consisting of one or more atoms with positive or negative charges. The forces that hold ions in a certain spatially oriented order of the crystal lattice are the forces of electrostatic attraction of oppositely charged ions that make up the crystal lattice.
If, for example, sodium chloride is dissolved in water, then the positively charged sodium ions and negatively charged chlorine ions will repel each other.
This repulsion occurs because water has a high dielectric constant, i.e. higher than that of any other liquid. It reduces the force of mutual attraction between oppositely charged ions by 100 times. The reason for the strong neutralizing effect of water must be sought in the arrangement of its molecules. The hydrogen atom in them does not share its electron equally with the oxygen atom to which it is attached. This electron is always closer to oxygen than to hydrogen. Therefore, hydrogen atoms are positively charged, and oxygen atoms are negatively charged.
When a substance dissolves into ions, oxygen atoms are attracted to positive ions, and hydrogen atoms are attracted to negative ions. The water molecules surrounding the positive ion send their oxygen atoms towards it, and the molecules that surround the negative ion send their hydrogen atoms towards it. Thus, water molecules form a kind of lattice, which separates the ions from each other and neutralizes their attraction (Fig. 12). In order to separate the ions located in the crystal lattice from each other and transfer them into solution, it is necessary to overcome the attractive force of this lattice. When dissolving salts, this force is the attraction of lattice ions by water molecules, characterized by the so-called hydration energy. If the hydration energy is sufficiently high compared to the energy of the crystal lattice, then the ions will break away from the latter and go into solution.
The relationship between water molecules and ions separated from the lattice in solution not only does not weaken, but becomes even closer.
As already noted, in a solution, ions are surrounded and separated by water molecules, which, focusing on them with their parts opposite in charge, form the so-called hydration shell (Fig. 13). The size of this shell is different for different ions and depends on the charge of the ion, its size and, in addition, on the concentration of ions in the solution.
For several years, physical chemists studied water mainly as a solvent for electrolytes. As a result, much information has been obtained about electrolytes, but very little about water itself. Oddly enough, only in recent years have works appeared devoted to the study of the relationship of water to substances that are practically insoluble in it.
Many amazing phenomena were observed. For example, one day a pipe carrying natural gas at t = 19°C turned out to be clogged with wet snow and water. It became clear that the problem here was not the temperature, but other properties of water. A number of questions arose: why water froze at such a high temperature, how water could combine with substances that are insoluble in it.
This mystery had not yet been solved when it was discovered that even such noble gases as argon and xenon, which do not enter into any chemical reactions, can combine with water, forming some semblance of compounds.
Rice. 13. Separation of Na + and C1 - ions by polar water molecules, forming a hydration shell around them.
Interesting results on the solubility of methane in water were obtained in Illinois. Methane molecules do not form ions in water and do not perceive hydrogen bonds; the attraction between them and water molecules is very weak. However, methane still, although poorly, dissolves in water, and its dissociated molecules form compounds with it - hydrates, in which several water molecules are attached to one methane molecule. This reaction releases 10 times more heat than dissolving methane in hexane (methane dissolves better in hexane than in water).
The fact that methane dissolves in water is of great interest. After all, a methane molecule has twice the volume of a water molecule. For methane to dissolve in water, quite large “holes” must form between its molecules. This requires a significant expenditure of energy, greater than for the evaporation of water (approximately 10,000 calories for each mole). Where does so much energy come from? The attractive forces between methane and water molecules are too weak, they cannot provide as much energy. Therefore, another possibility exists: the structure of the hearth changes in the presence of methane. Let's assume that a molecule of dissolved methane is surrounded by a shell of 10-20 water molecules. When such molecular associations form, heat is released. In the space occupied by a methane molecule, the forces of mutual attraction between water molecules, and hence the internal pressure, disappear. In such conditions, as we have seen, water freezes at temperatures above zero.
This is why molecules in the gap between methane and water can crystallize, which is what happened in the case described above. Frozen hydrates can be absorbed into the solution and released from it. This theory is known as the iceberg theory. In practice, as studies show, all non-conducting substances that were tested form stable crystalline hydrates. At the same time, this tendency is weakly expressed in electrolytes. All this leads to a completely new understanding of solubility.
It was believed that the dissolution of electrolytes occurs as a result of attractive forces. Now it has been proven that the dissolution of non-electrolytes occurs not due to the forces of attraction between these substances and water, but as a result of insufficient attraction between them. Substances that do not break down into ions combine with water, as they eliminate internal pressure and thereby contribute to the appearance of crystalline formations.
To better understand the formation of such hydrates, it is useful to consider their molecular structure.
It has been proven that the resulting hydrates have a cubic structure (lattice) in contrast to the hexagonal structure of ice. Further work by researchers showed that the hydrate can have two cubic lattices: in one of them the gaps between molecules are 12, in the other - 17 A. In the smaller lattice there are 46 water molecules, in the larger one 136. The holes of gas molecules in the smaller lattice have 12-14 faces , and in larger ones - 12-16, moreover, they vary in size and are filled with molecules of different sizes, and not all holes may be filled. This model explains the actual structure of hydrates with a high degree of accuracy.
The role of such hydrates in life processes can hardly be overestimated. These processes occur mainly in the spaces between water and protein molecules. Water has a strong tendency to crystallize, since the protein molecule contains many non-ionic, or non-polar, groups. Any such hydrate forms at a lower density than ice, so its formation can lead to significant destructive expansion.
So, water is a unique and complex substance with certain and varied chemical properties. It has a slender and at the same time changing physical structure.
The development of all living and, to a large extent, inanimate nature is inextricably linked with the characteristic features of water.
Water is one of the most abundant compounds on Earth. It is not only in rivers and seas; All living organisms also contain water. Life is impossible without it. Water is a good solvent (various substances dissolve easily in it). Animal and plant sap consist primarily of water. Water exists forever; it constantly moves from the soil to the atmosphere and organisms and back. More than 70% of the earth's surface is covered with water.
What is water
The water cycle
The water of rivers, seas, and lakes constantly evaporates, turning into tiny drops of water vapor. Drops gather together to form, from which water spills onto the ground in the form of rain. This is the water cycle in nature. In clouds of vapor we cool and return to earth in the form of rain, snow or hail. Wastewater from sewers and factories is treated and then discharged into the sea.
Water station
River water necessarily contains impurities, so it must be purified. Water enters reservoirs, where it settles and solid particles settle to the bottom. The water then passes through filters that trap any remaining solids. The water percolates through layers of clean gravel, sand or activated carbon, where it is cleaned of dirt and solid impurities. After filtration, the water is treated with chlorine to kill pathogenic bacteria, after which it is pumped into reservoirs and supplied to residential buildings and factories. Before wastewater goes into the sea, it must be treated. At a water treatment plant, it is passed through filters that trap dirt, then pumped into settling tanks where solids are allowed to settle to the bottom. Bacteria destroy the remains of organic substances, decomposing them into harmless components.
Water purification
Water is a good solvent, so it usually contains impurities. You can purify water using distillation(see article “”), but a more effective cleaning method is deionization(desalting). Ions are atoms or molecules that have lost or gained electrons and, as a result, have received a positive or negative charge. For deionization, a substance called ionite. It contains positively charged hydrogen ions (H+) and negatively charged hydroxide ions (OH -). When contaminated water passes through the resin, the impurity ions are replaced by hydrogen and hydroxide ions from the resin. Hydrogen and hydroxide ions combine to form new water molecules. Water that has passed through the ion exchanger no longer contains impurities.
Water as a solvent
Water is an excellent solvent; many substances easily dissolve in it (see also the article ““). This is why pure water is rarely found in nature. In a water molecule, the electrical charges are slightly separated because the hydrogen atoms are located on one side of the molecule. This is why ionic compounds (compounds made of ions) dissolve so easily in it. The ions are charged and water molecules attract them.
Water, like all solvents, can only dissolve a limited amount of a substance. A solution is called saturated when the solvent cannot dissolve an additional portion of the substance. Typically, the amount of substance that a solvent can dissolve increases with heating. Sugar dissolves more easily in hot water than in cold water. Fizzy drinks are water vapors of carbon dioxide. The higher , the more gas the solution can absorb. Therefore, when we open a can of drink and thereby reduce the pressure, carbon dioxide escapes from the drink. When heated, the solubility of gases decreases. About 0.04 grams of oxygen is usually dissolved in 1 liter of river and sea water. This is enough for algae, fish and other inhabitants of seas and rivers.
Hard water
Hard water contains dissolved minerals that came from the rocks through which the water flowed. 
Soap does not lather well in such water because it reacts with minerals and forms flakes. There are two types of hard water; the difference between them is the type of dissolved minerals. The type of minerals dissolved in water depends on the type of rock through which the water flows (see figure). Temporary water hardness occurs when limestone reacts with rainwater. Limestone is an insoluble calcium carbonate, and rainwater is a weak solution of carbonic acid. The acid reacts with calcium carbonate to form bicarbonate, which dissolves in water and makes it hard.
When water with temporary hardness boils or evaporates, some of the minerals precipitate, forming scale at the bottom of the kettle or stalactites and stalagmites in the cave. Water with constant hardness contains other calcium and magnesium compounds, such as gypsum. These minerals do not precipitate when boiled.
Water softening
You can remove minerals that make water hard by adding washing soda to the solution or through ion exchange, a process similar to deionization of water during purification. A substance containing sodium ions that exchange with calcium and magnesium ions found in water. In the ion exchanger, hard water passes through zeolite- substance containing sodium. In zeolite, calcium and magnesium ions are mixed with sodium ions, which do not add hardness to the water. Washing soda is sodium carbonate. In hard water, it reacts with calcium and magnesium compounds. The result is insoluble compounds that do not form flocs.
Water pollution
When untreated water from factories and homes enters the seas and rivers, water pollution occurs. If there is too much waste in the water, bacteria that decompose organic matter multiply and consume almost all the oxygen. Only pathogenic bacteria that can live in water without oxygen survive in such water. When the level of dissolved oxygen in water decreases, fish and plants die. Garbage, pesticides and nitrates from fertilizers, toxic ones - lead and mercury, also get into the water. Toxic substances, including metals, enter the body of fish, and from them into the bodies of other animals and even humans. Pesticides kill microorganisms and animals, thereby disturbing the natural balance. Fertilizers from the fields and detergents containing phosphates, when released into the water, cause increased plant growth. Plants and bacteria that feed on dead plants absorb oxygen, reducing its content in the water.
Brief description of the role of water for organisms
Water is the most important inorganic compound, without which life on earth is impossible. This substance is both the most important part and plays an important role as an external factor for all living beings.
On planet Earth, water is found in three states of aggregation: gaseous (vapor in, liquid (water in and foggy in the atmosphere) and solid (water in glaciers, icebergs, etc.). The formula for vapor water is H 2 O, liquid (H 2 O) 2 (at T = 277 K) and (H 2 O) n - for solid water (ice crystals), where n = 3, 4, ... (depends on temperature - the lower the temperature, the greater the value of n). Water molecules combine into particles with the formula (H 2 O) n as a result of the formation of special chemical bonds, called hydrogen; such particles are called associates; due to the formation of associates, more loose structures arise than liquid water, therefore, at temperatures below 277 K, the density of water is unlike other substances, it does not increase, but decreases, as a result, ice floats on the surface of liquid water and deep reservoirs do not freeze to the bottom, especially since water has low thermal conductivity. This is of great importance for organisms living in water - they do not. die in severe frosts and survive during winter cold until the onset of more favorable temperature conditions.
The presence of hydrogen bonds determines the high heat capacity of water, which makes life on the surface of the Earth possible, since the presence of water helps to reduce the temperature difference between day and night, as well as in winter and summer, because when cooled, water condenses and heat is released, and when heated, water evaporates, to The breaking of hydrogen bonds is spent and the Earth's surface does not overheat.
Water molecules form hydrogen bonds not only with each other, but also with molecules of other substances (carbohydrates, proteins, nucleic acids), which is one of the reasons for the emergence of a complex of chemical compounds, as a result of the formation of which the existence of a special substance is possible - a living substance that forms various .
The ecological role of water is enormous and has two aspects: it is both an external (first aspect) and an internal (second aspect) environmental factor. As an external environmental factor, water is part of abiotic factors (humidity, habitat, component of climate and microclimate). As an internal factor, water plays an important role inside the cell and inside the body. Let's consider the role of water inside the cell.
In a cell, water performs the following functions:
1) the environment in which all the organelles of the cell are located;
2) a solvent for both inorganic and organic substances;
3) an environment for the occurrence of various biochemical processes;
4) a catalyst for exchange reactions between inorganic substances;
5) a reagent for the processes of hydrolysis, hydration, photolysis, etc.;
6) creates a certain state of the cell, for example turgor, which makes the cell elastic and mechanically strong;
7) performs a construction function, which consists in the fact that water is part of various cellular structures, for example membranes, etc.;
8) is one of the factors that unites all cellular structures into a single whole;
9) creates electrical conductivity of the medium, transferring inorganic and organic compounds into a dissolved state, causing electrolytic dissociation of ionic and highly polar compounds.
The role of water in the body is that it:
1) performs a transport function, since it transforms substances into a soluble state, and the resulting solutions due to various forces (for example, osmotic pressure, etc.) move from one organ to another;
2) performs a conductive function due to the fact that the body contains electrolyte solutions capable of conducting electrochemical impulses;
3) connects together individual organs and organ systems due to the presence of special substances (hormones) in water, while carrying out humoral regulation;
4) is one of the substances that regulate the body temperature of the body (water in the form of sweat is released onto the surface of the body, evaporates, due to which heat is absorbed and the body cools);
5) is included in food products, etc.
The importance of water outside the body is described above (habitat, regulator of external temperature, etc.).
For organisms, fresh water plays an important role (salt content less than 0.3%). In nature, chemically pure water practically does not exist; the purest is rainwater from rural areas, far from large populated areas. Water contained in fresh water bodies - rivers, ponds, fresh lakes - is suitable for organisms.
Margarita Khalisova
Lesson summary “Water is a solvent. Water purification"
Subject: Water is a solvent. Water purification.
Target: consolidate the understanding that substances in water do not disappear, but dissolve.
Tasks:
1. Identify substances that dissolve in water and which are not dissolve in water.
2. Introduce the cleaning method water – by filtration.
3. Create conditions for identifying and testing various cleaning methods water.
4. Consolidate knowledge about the rules of safe behavior when working with various substances.
5. Develop logical thinking by modeling problem situations and solving them.
6. Cultivate accuracy and safe behavior when working with various substances.
7. Cultivate interest in cognitive activity and experimentation.
Educational areas:
Cognitive development
Social and communicative development
Physical development
Vocabulary work:
enrichment: filter, filtering
activation: funnel
Preliminary work: conversations about water, its role in human life; conducted observations of water in kindergarten and at home; experiments with water; looked at illustrations on the topic « Water» ; became familiar with safety rules during research and experimentation; asking riddles about water; reading fiction, environmental fairy tales; games about water.
Demonstration and visual material: doll in blue suit "Droplet".
Handout: empty glasses with water; solvents: sugar, salt, flour, sand, food coloring, vegetable oil; plastic spoons, funnels, gauze napkins, cotton pads, oilcloth aprons, mugs of tea, lemon, jam, disposable plates, oilcloth for tables.
GCD move
Educator: - Guys, before starting a conversation with you, I want to wish you riddle:
Lives in seas and rivers
But it often flies across the sky.
How will she get bored of flying?
It falls to the ground again. (water)
Can you guess what the conversation will be about? That's right, about water. We already know that water is a liquid.
Let's remember what properties water we established with the help of experiments on others classes. List.
Children:
1. U water has no smell.
2. No taste.
3. It's transparent.
4. Colorless.
5. Water takes the shape of the vessel into which it is poured.
6. Has weight.
Educator: - Right. Do you want to experiment with water again? To do this, we need to briefly turn into scientists and look into our laboratory experimentation:
Turn right, turn left,
Find yourself in the laboratory.
(children approach the mini-laboratory).
Educator: - Guys, look who’s visiting us again? And what's new in the laboratory?
Children: - "Droplet", granddaughter of grandfather Knowing and beautiful box.
Want to know what's in this box? Guess puzzles:
1. Separately, I’m not so tasty,
But in food - everyone needs (salt)
2. I'm white as snow
Everyone is honored.
Got it in my mouth -
There he disappeared. (sugar)
3. They bake cheesecakes from me,
And pancakes and pancakes.
If you are making dough,
They must put me down (flour)
4. Yellow, not the sun,
It's pouring, not water,
It's foaming in the pan,
Splashes and hisses (oil)
Food coloring - used in cooking to decorate cakes and color eggs.
Sand - for construction, play with it in the sandbox.
Children examine test tubes with substances.
Educator: - I brought all these substances "Droplet" so that we can help her understand what will happen to water when interacting with them.
Educator: - What do we need to start our work with water?
Children: - Aprons.
(children put on oilcloth aprons and go to the table, where there are glasses of clean water on a tray).
Educator: - Let's remember the rules before we start working with these substances:
Children:
1. You cannot taste the substances - there is a possibility of poisoning.
2. You must sniff carefully, as the substances can be very caustic and can burn your respiratory tract.
Educator: - Danil will show you how to do it correctly (directing the smell from the glass with his palm).
I. Research Job:
Educator: - Guys, what do you think will change if dissolve these substances in water?
I listen to the children’s expected results before mixing the substances with water.
Educator: - Let's check.
I suggest that the children each take a glass of water.
Educator: - Look and determine which one is there water?
Children: - The water is clear, colorless, odorless, cold.
Educator: - Take a test tube with the substance you have chosen and dissolve in a glass of water, stirring with a spoon.
We are considering. I listen to the children's answers. Did they guess correctly?
Educator: - What happened to sugar and salt?
Salt and sugar quickly dissolve in water, the water remains clear, colorless.
Flour too dissolve in water, But the water becomes cloudy.
But after the water will stand for a while, the flour settles to the bottom, but solution continues to be cloudy.
Water with sand it became dirty, cloudy, if you don’t stir it anymore, the sand sank to the bottom of the glass, it can be seen, i.e. it doesn’t dissolved.
food powder solvent quickly changed color water, Means, dissolves well.
Oil is not dissolves in water: it's either spreads on its surface as a thin film, or floats in the water in the form of yellow droplets.
Water is a solvent! But not all substances dissolve in it.
Educator: - Guys, we worked with you and "Droplet" invites us to rest.
(Children sit at another table and a game is played.
A game: “Guess the taste of the drink (tea)».
Tea drinking with different flavors: sugar, jam, lemon.
II Experimental work.
We approach table 1.
Educator: - Guys, is it possible to purify water from these substances that we dissolved? Return it to its previous state of transparency, without sediment. How to do it?
I suggest you take your glasses from solutions and go to table 2.
Educator: - You can filter it. For this you need a filter. What can a filter be made from? We will do it using a gauze napkin and a cotton pad. I show you (I put a gauze napkin folded in several layers and a cotton pad into the funnel and put it in an empty glass).
Making filters with children.
I show the method of filtering, and then the children themselves filter the water with the substance they chose.
I remind the children not to rush, pour in a small stream solution into a funnel with a filter. I'm talking proverb: “If you hurry, you’ll make people laugh”.
Let's look at what happened after filtering water with different substances.
The oil was filtered quickly because it was not dissolved in water, traces of oil are clearly visible on the filter. The same thing happened with sand. Practically no substances were filtered out that were good dissolved in water: sugar, salt.
Water with flour after filtering it became more transparent. Most of the flour settled on the filter, only very small particles slipped through the filter and ended up in the glass, so water not entirely transparent.
After filtering the dye, the color of the filter changed, but filtered solution also remained in color.
GCD result:
1. What substances dissolve in water? – sugar, salt, dye, flour.
2. Which substances are not dissolves in water - sand, oil.
3. With what cleaning method water we met? – filtering.
4. With what? – filter.
5. Did everyone follow the safety rules? (one example).
6. What's interesting (new) did you find out today?
Educator: - Today you learned that water is a solvent, checked what substances dissolve in water and how you can purify water from different substances.
"Droplet" thanks you for your help and gives you an album for sketching your experiments. With this our research is completed, we return from the laboratory to group:
Turn right, turn left.
You'll find yourself in the group again.
Literature:
1. A. I. Ivanova Ecological observations and experiments in kindergarten
2. G. P. Tugusheva, A. E. Chistyakova Experimental activities of middle and senior preschool children age St. Petersburg: Childhood-Press 2010.
3. Cognitive research activities of older preschoolers - Child in kindergarten No. 3,4,5 2003.
4. Research activity of a preschooler - D/v No. 7, 2001.
5. Experimenting with water and air - D/V No. 6, 2008.
6. Experimental activities in kindergarten - Teacher of preschool educational institution No. 9, 2009.
7. Games - experimentation of a younger preschooler - Preschool pedagogy No. 5 2010.
Task: Show children the solubility and insolubility of various substances in water.
Materials: flour, granulated sugar, river sand, food coloring, washing powder, glasses of clean water, spoons or chopsticks, trays, pictures depicting the substances presented.
Description. In front of the children on trays are glasses of water, chopsticks, spoons and substances in various containers. Children look at water and remember its properties. What do you think will happen if granulated sugar is added to water? Grandfather Know adds sugar, mixes, and everyone observes together what has changed. What happens if we add river sand to the water? Adds river sand to the water and mixes. Has the water changed? Did it become cloudy or remain clear? Has the river sand dissolved?
What will happen to water if we add food coloring to it? Adds paint and mixes. What changed? (The water has changed color.) Has the paint dissolved? (The paint dissolved and changed the color of the water, the water became opaque.)
Will flour dissolve in water? Children add flour to the water and mix. What did the water become? Cloudy or clear? Did the flour dissolve in the water?
Will washing powder dissolve in water? Add washing powder and mix. Did the powder dissolve in water? What did you notice that was unusual? Dip your fingers into the mixture and check if it still feels the same as clean water? (The water has become soapy.) What substances have dissolved in our water? What substances do not dissolve in water?
(The results are recorded on a flannelgraph.)
COLORED SAND
Tasks: introduce children to the method of making colored sand (mixing with colored chalk); teach how to use a grater.
Materials: colored crayons, sand, transparent container, small objects, 2 bags, small graters, bowls, spoons (sticks), small jars with lids.
Description. The little jackdaw, Curiosity, flew to the children. He asks the children to guess what is in his bags. Children try to determine by touch. (In one bag there is sand, in the other there are pieces of chalk.) The teacher opens the bags, the children check their guesses. The teacher and the children examine the contents of the bags. What is this? What sand? What can you do with it? What color is chalk? What does it feel like? Can it be broken? What is it for? Little Gal asks: “Can sand be colored? How to make it colored? What happens if we mix sand with chalk? How can you make chalk as free-flowing as sand?” Little Gal boasts that he has a tool for turning chalk into fine powder.
Shows the children the grater. What is this? How to use it? Children, following the example of the little jackdaw, take bowls, graters and rub chalk. What happened? What color is your powder? (The little pebble asks each child) How can I make the sand colored now? Children pour sand into a bowl and mix it with spoons or chopsticks. Children look at colored sand. How can we use this sand? (Make beautiful pictures.)
Little Galchoff offers to play. Shows a transparent container filled with multi-colored layers of sand and asks the children: “How can you quickly find a hidden object?” Children offer their own options. The teacher explains that you cannot mix the sand with your hands, a stick or a spoon, and shows how to push an object out of the sand by shaking the vessel.
What happened to the colorful sand? The children note that in this way we quickly found the object and mixed the sand.
Children hide small objects in transparent jars, cover them with layers of multi-colored sand, close the jars with lids and show the little girl how they quickly find the hidden object and mix the sand. Little Galchon gives the children a box of colored chalk as a farewell gift.
GAMES WITH SAND
Tasks: consolidate children’s ideas about the properties of sand, develop curiosity and observation, activate children’s speech, and develop constructive skills.
Materials: a large children's sandbox, in which traces of plastic animals are left, animal toys, scoops, children's rakes, watering cans, a plan of the area for walks of this group.
Description. Children go outside and explore the walking area. The teacher draws their attention to unusual footprints in the sandbox. Why are footprints so clearly visible in the sand? Whose tracks are these? Why do you think so?
Children find plastic animals and test their guesses: they take toys, place their paws on the sand and look for the same print. What trace will be left from the palm? Children leave their marks. Whose palm is bigger? Whose is smaller? Check by applying.
The teacher finds a letter in the bear cub's paws and takes out a site plan from it. What is shown? Which place is circled in red? (Sandbox.) What else could be interesting there? Perhaps some kind of surprise? Children, plunging their hands into the sand, look for toys. Who is this?
Each animal has its own home. The fox has... (hole), the bear has... (den), the dog has... (kennel). Let's build a sand house for each animal. What sand is best for building with? How to make it wet?
Children take watering cans and water the sand. Where does the water go? Why did the sand become wet? Children build houses and play with animals.