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Introduction
It can be colored or white, Children love to draw with it, He is an artist, in skillful hands, He can create paintings! We can’t do repairs without it, And we can’t whitewash the ceiling, And we can use It in a whole lot of useful things. The teacher gives them the words, For the kids at school on the blackboard, Who is he, the riddles of this resident, Living in a small piece?
This mysterious resident is school chalk. Yes, this is that simple piece of chalk that every person has known since childhood.
Chalk is a very interesting substance, which is at the same time a mineral, a chemical raw material, and medicine, and a reliable home assistant. At every lesson, when we go to the school board, we excitedly pick up a piece of chalk. Otherwise, how can you learn something new?
Why is chalk so convenient for writing and drawing? Where did he come from? What does it consist of? Why do teachers complain about chalk, but children love it?
I became interested and decided to do research to find out what chalk is and what its secrets are.
Target: study the structure of school chalk and reveal its properties
Tasks:
Study the history of chalk;
study the properties of chalk and its structure;
find out how the use of chalk affects the health of schoolchildren and teachers;
present research results to classmates.
Hypothesis:
chalk has beneficial features and indispensable in everyday life;
Subject of study: school chalk
Main part
History of chalk
To find out everything about chalk, I studied encyclopedic literature and analyzed materials from the Internet. It turns out that the Cretaceous period existed on Earth, and it was then that chalk began to form.
Chalk has both plant and animal origin. It consists of calcareous algae, as well as crustaceans and snails, which were extracted from sea water calcium and built their shells and skeletons.
When they died, these plants and animals sank to the bottom and accumulated there. Over time, a thick layer of these remains formed. Of course, this took millions of years. Gradually, this layer cemented on the ocean floor and turned into soft limestone, which we call chalk.
Composition of natural and school chalk
Chalk is limestone composed of microorganisms and algae. That is, chalk is a sedimentary rock - semi-hardened silt, in which shells of mollusks and snails are found.
In nature it is Chemical substance It is found in various forms - it is made up of mollusk shells and corals, pearls and eggshells, school chalk and marble, limestone and clear Icelandic spar crystals.
The natural chalk used to make school chalk comes from quarries . It is absolutely safe and does not contain foreign impurities. For the production of good natural school chalk white chalk specially prepared. First, it is broken into small pieces, sorted, all impurities are removed and ground on a millstone with the addition of water.
The resulting mass is left to settle, allowing heavy impurities such as sand and stones to settle to the bottom of the vessel. The solution of the purer material is poured into the second vessel, and then into the next, until all unnecessary impurities fall to the bottom and are removed from the chalk solution.
The resulting mass is left to sit in a vat for a long time, then the water is drained, and the remaining mass is poured into a linen-covered box. The drained mass is dried on a wire rack. If the dried chalk becomes too crumbly, add a little glue to it. And with the help of various dyes you can get crayons of any color.
Human use of chalk
A lot of chalk is mined. Where does it find application? Chalk is used in many areas:
No school is complete without chalk, which is successfully used for writing on large blackboards.
In medicine, chalk is used for calcium deficiency, as a food additive. Its use has a great effect on strengthening nails, teeth and bones.
Chalk is widely used in industry:
in glass production;
for the production of matches;
for making drinking soda;
in the manufacture of rubber;
for the production of cement, varnishes, paints;
for obtaining window profiles, pipes and even finishing siding;
in the printing and paper industry.
IN agriculture chalk is added to the soil to reduce its acidity, as well as to make animal feed.
In perfumery, chalk is component tooth powders and pastes.
Chalk is also perfectly used for painting fences, borders, walls, for protecting tree trunks from sunburn, for whitewashing ceilings, for controlling plant diseases and pests in the garden, for cleaning tableware and kitchen utensils.
You see: everyone, everywhere needs chalk!
The effects of school chalk on human health
We learned from the media that Russian teachers are against teachers working with chalk: it is dangerous to health!
The fact is that this is a product containing, in addition to the main safe components (limestone, gypsum and starch), adhesives and dyes.
In addition, during use, school chalk begins to gather dust, settle on clothes and furniture, get into your nose, and stain your hands.
I was wondering - is chalk really that dangerous to health?
Practical part
Questioning students to study their knowledge about school chalk
Having learned a lot of interesting things about chalk, I prepared a questionnaire ( Appendix No. 1) ,to survey classmates and teachers to understand what classmates know about such useful material and how they feel when working with chalk. I conducted a survey on the following questions:
Does chalk affect your health?
What is chalk made of?
What does chalk have in common with pearls and shells? chicken egg and teeth?
What sensations do you experience when working with chalk?
29 students and 3 teachers took part in the survey.
The survey results are located in the table: ( Appendix No. 2). After the survey, we became convinced that school teachers knew a lot about the origin and composition of chalk, but students knew little. But teachers will also be interested in learning about the possibilities of protecting hands from chalk and how to use chalk in everyday life.
Conclusion: Students will find it useful and interesting to listen to our message about the origin, properties and uses of chalk.
Study of the composition and properties of chalk
If you touch school chalk with your hands, it is hard and rough. When we write on the board, it crumbles, crumbles, which means it is fragile. If you rub chalk on your hand, it leaves a mark, which means it gets dirty.
If you put chalk in water, it becomes cloudy, which means that the chalk does not dissolve in water. What does it consist of?
Experiment 1 (Appendix No. 3 “Chalk under a microscope »)
We decided to look at the chalk under a microscope.
They took a piece of chalk, placed it in a mortar and crushed it. Then mixed the chalk with water. The resulting slurry was placed on glass. The glass was placed under a microscope.
We saw white lumps, these are large pieces of chalk. It seemed to us that they really resembled pieces of shells.
And those smaller pieces were dark. Perhaps they are just grains of sand.
Conclusion: chalk consists of the remains of microorganisms and algae and various impurities.
If the chalk was formed from shells with shells made of lime, then the chalk is made of limestone. Is this really true? We decided to conduct another experiment.
Experiment 2 (Appendix No. 4 “Interaction of chalk and acid”)
A little vinegar was poured into the glass. We put chalk there. The vinegar began to bubble violently. Then small pieces began to break off from the chalk. My mother told me that vinegar is an acid. Chalk consists of limestone, which, when interacting with acid, is destroyed and released carbon dioxide, which is what we saw during the experiment. The interaction of vinegar with chalk.
Conclusions:
- chalk consists of limestone (calcium);
Calcium is destroyed by acid.
We also learned that pearls, marble, eggshells and teeth also contain calcium. This means they must be protected from exposure to acids.
For example, juices should be drunk through a straw; marble sculptures in the park should be protected from the rain. But scale in a kettle can be removed using citric acid!
We have pieces of chalk in our classroom different shapes. Round chalk doesn't write very well on the blackboard; it crumbles a lot and gets your hands dirty.
Other crayons, including multi-colored ones, leave a very bright mark on the board, don’t crumble as much, and your hands are cleaner after them. I thought: " Why is this happening?»
Experiment 3 (Appendix No. 5 “Interaction of chalk and iodine”)
We took crayons of different shapes and dropped a drop of iodine onto them. It turns out that starch can change the color of iodine. The color of the iodine speck on the cylindrical crayon changed to blue-violet.
On other chalk samples the coloring alcohol solution Yoda has not changed. So, in different types chalk has different additives: some contain, for example, starch, and others, probably, glue.
Interaction of chalk with iodine
Conclusion: Round crayons contain starch.
Studying the effect of school chalk on human health
I was interested in the question of whether chalk affects human health. I asked this question to 3 teachers and 29 classmates.
« Yes" - answered 19 students, " No» - 3 teachers and 4 students, Don't know- 5 students
It seems to me that our classmates answered this question this way because they really like chalk, they like to draw with it on the blackboard and on the asphalt.
I asked more questions:
What is chalk made of?
Here the answers were divided almost evenly.
From limestone - 5 people, from calcium - 9 people, from minerals - 9 people, I don’t know - 9 people.
“Nothing” was answered by 5 people, “they contain calcium” - 20 people, “I don’t know” - 6 people.
How do you feel when working with chalk?
The majority of respondents noted that school chalk has a negative effect on the skin of their hands:
Hand skin dries - 26 people;
Causes allergies -0 people;
Breathing problems - 2 people;
Coughing attacks - 2 people
Some of the teachers surveyed noted that due to cracks in their skin, they constantly use hand moisturizer.
After reading the book " The main wonder of the world", we learned that a person has sweat glands under the skin. If after using chalk the skin on your hands becomes dry, it means that the chalk absorbs moisture and oil.
We conducted an experiment.
Experiment 4 (Appendix No. 6 “Interaction of chalk with water and oil”)
I took 2 plates. Water was poured into the first, a little vegetable oil into the second. They put a piece of chalk in each. The chalk absorbed the water very quickly, the oil more slowly, but the plate also turned out to be almost dry.
Conclusion: chalk dries the skin of your hands because it absorbs water and oil well.
To decrease Negative influence chalk on the skin of your hands, you can wrap the chalk with tape or insert a piece of chalk into a lipstick case
To prevent the chalk from crumbling, you need to dry it on a radiator and store it in a dry place.
Rinse the chalk rag as often as possible;
Teachers should use wet wipes while working;
The attendants should ventilate the classroom more often;
Wipe chalk from the board only with a damp cloth;
Conclusion
Having completed the work, I learned how chalk appeared and what it consists of;
conducted a number of experiments and studied the properties of chalk;
found out how the use of chalk affects human health;
collected information about the use of chalk in human life;
conducted a survey among teachers and classmates to study their knowledge about school chalk.
The hypothesis turned out to be correct, I found out that chalk has an effect on human health and is indispensable in everyday life. Its scope of application is very wide: it is everyday life humans, medicine, industry, agriculture, and chalk is still indispensable in school lessons. But despite its importance, chalk can be dangerous and cause harm to human health, so when using it you need to be careful and follow the recommendations for safe use chalk.
List of sources and literature used
I explore the world: Children's encyclopedia: Chemistry / Author-comp. L.A. Savina. - M.: AST, 1999.
Encyclopedia of a young chemist.
“The Main Wonder of the World” G. Yudin / M.: Publishing House “ Interesting book", 2017
Encyclopedia for children. Volume 17 Chemistry. / Chief editor V.A. Volodin. - M.: Avanta+, 2000
Funny chemical experiments//Magazine “Masterilka” (05/11/2010) Publ. "Karapuz"
Chalk Wikipedia
Appendix No. 1
Questionnaire
Does chalk affect human health?
Yes________ no________ I don’t know_______
What is chalk made of?
Limestone______ calcium________ minerals______ I don’t know_______
What does chalk have in common with pearls, chicken egg shells and teeth?
Nothing_______
Don't know _______
The skin on your hands is dry_____
I'm allergic to chalk_____
breathing problems_____
coughing fits_______
coughing fits_______
Appendix No. 2
Survey results
|
№ p/p |
Question |
Result |
|
Does chalk affect human health? |
Yes -19 No - 5 students and 3 teachers I don't know -5 |
|
|
What is chalk made of? |
- Made of limestone - 4 people; - From calcium - 11 people; - I don’t know - 8 people; - From minerals - 9 people |
|
|
What does chalk have in common with pearls? chicken egg shell and teeth |
Nothing: 5 lessons I don't know: 6th grade They are all made of calcium: 20 uch 3 teachers - 100% |
|
|
What unpleasant sensations do you experience when working with chalk? |
- Hand skin dries out - 22 students, and 3 teachers - I am allergic to chalk - 0 people, - Breathing problems - 2 students - Coughing attacks - 2 frequent. |
|
Appendix No. 3
Chalk under a microscope
Appendix No. 4
Interaction of chalk with acid
Appendix No. 5
Interaction of chalk with iodine
Appendix No. 6
Interaction of chalk with water and oil
to reduce the negative impact of chalk on the skin of your hands, you can wrap the chalk with tape or insert a piece of chalk into a lipstick case;
To make school chalk non-staining, just dip it for a few seconds in milk diluted 2-3 times. After this procedure, the chalk will no longer get dirty, and writing will still be good;
To prevent the chalk from crumbling, you need to dry it on a radiator and store it in a dry place.
For decreasing negative consequences that appear due to constant contact with chalk, we recommend:
use wet wipes while working;
duty officers - to ventilate the classroom more often;
wipe chalk from the board only with a damp cloth;
wash the chalk rag as often as possible;
at the end working week A school employee can wash the board with a cloth soaked in water and vinegar.
When we talked about why soap washes, we mentioned the special structure of its molecule: a “head” and a long “tail”, and the “head” tends towards the water, and the “tail”, on the contrary, repels from the water... Let's take a closer look hydrophobic"tail" - long hydrocarbon chain. These types of connections are very common and extremely important for industry. They are an indispensable component of many fats, oils, lubricants and other beneficial substances. One of them is the so-called stearin- we will get it now, using laundry soap as a basis.
Use a knife to cut half a piece of laundry soap and place it in a clean tin can(or into a used saucepan). Pour enough water to cover the soap shavings and place the mixture in a water bath. Stir the contents of the saucepan from time to time with a wooden stick so that the soap dissolves in the water as quickly as possible. When this finally happens, remove the vessel from the heat (of course, do not bare hand) and pour vinegar into it.
Under the action of acid, a thick white mass will separate from the solution and float to the surface. That's what it is stearin- a translucent mixture of several substances, mainly stearic C 17 H 35 COOH and palmitic C 15 H 31 COOH acids. It is impossible to say the exact composition; it depends on the substances that went into making the soap.
From stearin, as you know, make candles. Or rather, they did it before, because now there are candles for the most part Not stearic, A paraffin- derived from petroleum paraffin cheaper and more accessible. But, since we have stearin at our disposal, we will make a candle from it. This, by the way, is a fun activity in itself!
When the jar has cooled completely, scoop the stearin from the surface with a spoon and transfer it to a clean container. Rinse the stearin two or three times with water and wrap it in a clean white rag or filter paper to absorb excess moisture. When the stearin is completely dry, let's start making the candle.
Here is perhaps the simplest technique: dip a thick twisted thread, for example, from a kerosene stove wick, repeatedly into slightly heated molten stearin, each time allowing the stearin to harden on the wick. Do this until the candle grows to a sufficient thickness on the wick. This good way, although somewhat tedious; in any case, in ancient times candles were often prepared this way.
There is a simpler way: immediately coat the wick with stearin heated until softened (you can even just prepare it, not yet cooled down). But in this case, the wick will be less saturated with the fusible mass and the candle will not turn out very good, although it will burn.
For beautiful, shaped candles, the manufacturing methods are not easy. And first of all, you need to make a mold - wooden, plaster, metal. In this case, it is advisable to first soak the wick with one or two layers of stearin; it is then secured in the mold so that it runs exactly down the middle. It is advisable that the wick be slightly stretched. And after that, hot stearin is poured into the mold.
By the way, in this way you can make candles from paraffin, i.e., actually, from purchased candles, melting them and giving them the shape that you like. However, we warn you - you will have to tinker...
Having received a candle from soap, let's conduct the experiment in the opposite direction: prepare candle soap. But not from paraffin soap; soap cannot be made from it at all, because paraffin molecules do not have “heads.” But if you are sure that the candle is stearic, then you can safely make laundry soap from it. Natural is also suitable beeswax.
Several fragments of a stearin candle heat in a water bath, hot enough, but not brought to a boil. When the stearin is completely melted, add a concentrated solution to it washing(calcified) soda. The resulting white viscous mass is soap. Hold it for a few more minutes in a water bath, and then, putting on a mitten or wrapping your hand in a towel so as not to get burned, pour the still hot mass into some form - at least into a matchbox. When the soap has hardened, remove it from the box.
Making sure that it is soap and that it cleans is not difficult. Just please don’t use it to wash your hands - we don’t know how pure the substances that made up the candle were.
Moisten a piece of natural chalk CaCO 3 with a drop of hydrochloric acid HCl (you can take pharmaceutical acid). Where the drop fell, energetic boiling is noticeable. Place a piece of chalk with a “boiling” drop into the flame of a candle or dry alcohol. The flame will turn a beautiful red color.
This is a well-known phenomenon: calcium, which is part of chalk, makes the flame red. But why acid? Reacting with chalk, it forms soluble calcium chloride CaCl 2, its splashes are carried away by gases and fall directly into the flame - this makes the experience more effective.
Unfortunately, such an experiment with pressed school chalk does not work - it contains an admixture soda(sodium salts), and the flame is colored V Orange color . The best experience is with a piece white marble, soaked in the same acid.
And make sure that sodium salts color the flame intensely yellow, you can by adding a grain of NaCl salt to the flame (or simply “salting” the fire slightly).
For the next experiment with chalk, you will need a candle. Strengthen it on a non-flammable stand and add a piece of chalk (marble, shell, eggshell) to the flame. The chalk becomes covered with soot, which means the flame temperature is low. We are going to burn chalk, and for this we need a temperature of 700-800 o C. What should we do? It is necessary to increase the temperature by blowing air through the flame.
Remove the rubber cap from the medicine pipette and replace it with a rubber or plastic tube. Blow into the tube so that air enters the flame just above the wick through the drawn end of the pipette. The flame will deviate to the side, its temperature will increase.
Point the tongue at the sharpest part of the crayon. This area will become white hot, chalk will turn into burnt(quicklime) lime CaO, and at the same time it will stand out carbon dioxide.
Do this operation several times with the pieces chalk, marble, eggshell. Place the burned pieces in a clean tin. While they are cooling, place the largest piece in a saucer and drop some water on the place that was heated. There will be a hissing sound, all the water will be absorbed, and the baked area will crumble into powder. This powder is slaked lime Ca(OH) 2.
Add more water and drop the solution phenolphthalein. The water in the saucer will turn red; This means that slaked lime forms an alkaline solution.
When the burnt pieces have cooled, place them in a glass jar or bottle, fill with water, close the lid and shake - the water will become cloudy. You already know that we will now get lime water. Let the liquid settle and pour the clear solution into a clean bottle. Pour some limewater into a test tube - and you can use it to perform the previously described experiments with gases. And other tricks are possible.
Abstract research activities“An unusual piece of chalk” for senior preschool age.
(Properties, quality, human use of chalk)
Program content:
1. Enrich and expand children’s ideas about mele, him properties (flowability, hardness, friability, etc.), its application in the life and activities of people.
2. Strengthen the skill of research activities: the ability to identify the properties and qualities of chalk through experiments.
3. Continue working on developing children’s geographical understanding through familiarization with natural resources bowels of the Earth.
4. Develop cognitive abilities on a multisensory basis: with the help of analyzers - visual, gustatory, tactile, auditory and olfactory.
5. Develop the ability to work in small subgroups, be able to listen to the opinions of other members of the subgroup and defend their opinions.
6. Establish safety rules when conducting experiments (using algorithms)
7. Develop demonstrative speech, the ability to clearly justify your answer.
Activation of the dictionary: laboratory, scientific adviser, Researcher, sediment, crush, crumble, etc.
8. Cultivate in children curiosity, accuracy, and seriousness when performing experiments.
Preliminary work.
1. Consideration of collections of minerals and minerals: salt, granite, limestone, bauxite, clay, oil, etc.
2. Review and conversations on the map “Mineral Resources of the Russian Federation”,
3. Training session “Our generous Earth”
4. Examination and compilation of collages.
5. Reading and viewing children's and encyclopedic literature:
M. Kuryachaya “Chemistry in pictures”, Melikhova “Geography and you”, Atlas “Natural history” pp. 12-13 (Physical map of Russia), “My first atlas” - pp. 40-41 “Riches of the Earth”, A. Chlenov “Geology in pictures (What’s inside the mine, where the gasoline comes from, why the gas burns.), A. Ivich “70 heroes”
6. Drawing on the theme “Insects” using salt.
7. Consideration of the illustrative material “Professions of People.”
8. Conducting a series of experiments in the Pochemuchka laboratory to expand ideas about the properties and qualities of minerals: “Where sugar melts faster. Growing crystals (salt), comparing clay and sand.
9. Recording the results in observation diaries.
10. Conversations with children about safety rules when carrying out experiments.
Equipment:
Chalk - powder, colored pieces, vinegar, hourglass for three minutes, cold and hot water, spatulas, masher, measuring spoons, containers, containers, algorithm of safety rules for conducting experiments (salt and chalk), collages, observation diaries, glue, felt-tip pens , colour pencils.
Progress of the event
Children enter the hall to the music...
Educator:
Russia is great, but for each of us it begins from our native land.
Guys, what is the name of our native land?
Children: Belogorye.
Educator : That's right, dear fatherland. This is where you were born, this is where your closest people, your friends and comrades live. We all love this region - a part of our Motherland; we are proud of this region.
Children read a poem:
Favorite region! My Belgorod region!
How much I love you:
Chalk mountains and forests
Your rivers are streams, heaven.
I live in the Belgorod region,
I breathe freely and easily here,
I'm composing lines awkwardly
Streams of my poems flow here
I will glorify the dear land in lines!
Belgorod region! Live and prosper!
Children: The nature of our region is very picturesque. Endless fields blue rivers and lakes, forests and woodlands, snow-white peaks of chalk hills, which we majestically call “white mountains”.
The chalk mountains are one of the most breathtaking sights. From a distance, they resemble clouds that have descended to the ground to rest, or huge blocks of snow lying in the middle of green vegetation.
Educator: Guys, pay attention to the map of our region, how our region is rich in minerals... and especially chalk deposits, show them on the map.
Children, how did the chalk mountains appear?
Children: Millions of years ago, an ancient ocean stretched here. The chalk we walk on is nothing more thanthe bottom of the ancient ocean. It is known that it has never been lifeless. Various algae grew on it, sea lilies, lived mollusks, crustaceans, sea stars, hedgehogs. Over time, the remains of dead organisms (shells, shells, hard shells, skeletons) settled to the bottom and were buried in sediments in entire layers. They mixed with inorganic material and formed deposits of a kind of silt.
Over the years, the silt was replenished with new deposits, which became compacted due to the pressure of the upper layers on the lower ones, increased in volume, and became stronger. Eventually, they were cemented by various compounds contained in the solution that penetrated deep into the sediments.The tops of the surrounding hills have been washed by rains and “polished” by steppe winds for thousands of years, soft rocks crumbled, showing more solid formations- chalk pillars. This is how, from the point of view of geologists, Cretaceous deposits arose.
Educator: Guys, we already know a lot about chalk, but today let’s tell our guests what chalk is used for and where it is used?
Children: We know that they write with chalk at school and draw on the asphalt.
In industry, chalk is used to produce lime, cement, soda, glass, and school chalk. Used as a filler for rubber, plastics, paper, paints and varnishes. In agriculture for fertilizing soils and feeding animals, in perfumery - for preparing toothpastes and powders. Ground chalk is widely used as a cheap material for priming, whitewashing, painting the walls of houses, and for protecting tree trunks from sunburn.
Educator: Our region is also rich in chalk reserves, and in our city there is a chalk processing plant. Tell me, what is it called?
Children: Melzavod..
Educator: That's right guys, what properties of chalk do you know?
Children: White chalk; hard, but softer than stone; when they write to them, it crumbles, crumbles, which means it is fragile. Chalk leaves a mark and it gets dirty, dissolves in water,There is air inside the chalk.Chalk is limestone and upon contact with acetic acid it turns into other substances, one of which is carbon dioxide.
Educator:
Guys, let's tell you what experiments we conducted to find out the properties of chalk.
With water (stone and chalk).
When they lowered the stone into the water, nothing happened to the water; it remained transparent. And the stone remained the same.
And when they dipped the chalk into the water, they noticed that the water was clean and transparent, but became cloudy because the chalk dissolved in it. Chalk is limestone consisting of marine microorganisms, calcareous algae, it is hardened sea silt in which mollusk shells and skeletons are found sea urchins, lilies, even corals. WhenWe dropped a piece of chalk into a glass of water, then we saw bubbles because there is air inside the chalk.
Under a magnifying glass.
We looked at the chalk under a magnifying glass and saw small holes and blades of grass.
With vinegar and a piece of chalk.
We took half a glass of vinegar and a piece of chalk and threw a piece of chalk into the glass. When we carried out this experiment, we noticed that the vinegar in the glass began to bubble. Natalya Nikolaevna said that it was from huge amount gas bubbles coming out of the chalk. Gradually, small pieces fell off of it, and, in the end, it completely disintegrated. With the help of this experiment, we learned that chalk is limestone and when it comes into contact with acetic acid, it turns into other substances, one of which is carbon dioxide, which is rapidly released in the form of bubbles. In the same way, but very slowly, stone statues are destroyed due to the weak acid solution contained in the drops.
Making crayons
When we were drawing in a group on the board, we drew the teacher’s attention to the fact that there were few crayons left. Then Natalya Nikolaevna suggested making crayons ourselves. We took a mold, paints, water, plaster. IN plastic container we mixed plaster with water and added paint. Then we filled the molds with the mixture. And after 4 hours the crayons were ready!
Educator: Well done guys, and now I want to invite you to conduct experiments on your own, but first let’s warm up.
Physical education minute:
There is a mountain - an old woman,(raise hands up)
To the top of the sky(stretch on tiptoes)
The wind blows around her, (fan themselves with their hands)
The rain pours down on her,(shakes hands)
The mountain stands, suffers, loses stones(put palms to cheeks and shake head)
And every day and every night(the teacher touches several children, who must imitate pebbles).
The pebbles are rolling and rolling away.(some of the children move aside)
Educator:
Children, go behind your desks, find the chalk on your trays and look at it, touch it. What is he like?
Children: White chalk; hard, but softer than stone; when they write to them, it crumbles, crumbles, which means it is fragile.
Educator: Let's check it out! Try drawing a line of chalk across the board. What do you see? What did the chalk do?
Children: The chalk leaves a mark and it gets dirty.
Educator: Well done guys, you already know a lot about chalk.
The importance of chalk in people’s lives is great, but what is especially surprising are the unusual architectural objects that man has formed thanks to the richness of chalk deposits over many centuries, these are historically significant architectural monuments, temples and monasteries. The most striking of them are located on the territory of our homeland - in Belogorye, namely the monastery of Ignatius the God-Bearer,Holy Trinity Kholkovsky Monastery,Shmanenskaya Cave, Valuysky Assumption Nikolaevsky Monastery.
Holy Trinity Kholkovsky Monastery- the only active cave monastery inBelgorod region . Located inChernyansky district near the village Withers . The caves of the monastery are located in one of the chalk hills.
We learned that chalk plays a big role in people's lives, and we are proud that we live in the Belgorod region, which is rich in deposits of this valuable mineral.
And how many historical, cultural and architectural interweavings are associated with the presence of the mineral chalk, which in everyday life seems so banal that you don’t even notice it in everyday life.
Educator.
Chalk can also be used to make souvenirs. We decided to make a gift for moms, a rainbow in a jar.
To do this, we crushed colored chalk and poured semolina and chalk into a container with a lid and shaken several times. The semolina is colored! Then we carefully began to pour the semolina into the jar, changing colors.So we filled with layers of semolina different color the whole jar.
Educator: And how many riddles and poems about chalk we learned! The children and I found riddles about chalk and made a little book “White Pebble” as a gift for the groups.But we came across chalk not only in poems and riddles. We read S. Alekseeev’s story about Marshal Konev “Belgorod”. We really liked him!
Our group has a mini-museum “Belogorye”. After this work, we added the section “An Unusual Piece of Chalk” to the exhibition.
Since chalk occupies one of the leading positions in industrial development in the Belgorod region, while bearing historical, cultural and architectural value, it can rightfully be called the “white gold” of our region.
Chalk, marble, shell
Moisten a piece of natural chalk CaCO 3 with a drop of hydrochloric acid HCl (you can take pharmaceutical acid). Where the drop fell, energetic boiling is noticeable. Place a piece of chalk with a “boiling” drop into the flame of a candle or dry alcohol. The flame will turn a beautiful red color.
This is a well-known phenomenon: calcium, which is part of chalk, makes the flame red. But why acid? Reacting with chalk, it forms soluble calcium chloride CaCl 2, its splashes are carried away by gases and fall directly into the flame - this makes the experience more effective.
Unfortunately, such an experiment with pressed school chalk does not work - it contains an admixture of soda (sodium salt), and the flame turns orange. The best experience is obtained with a piece of white marble soaked in the same acid. And you can make sure that sodium salts color the flame an intense yellow color by adding a grain of NaCl salt to the flame (or simply lightly “salting” the fire).
For the next experiment with chalk, you will need a candle. Strengthen it on a non-flammable stand and add a piece of chalk (marble, shell, eggshell) to the flame. The chalk becomes covered with soot, which means the flame temperature is low. We are going to burn the chalk, and this requires a temperature of 700-800 °C. How to be? It is necessary to increase the temperature by blowing air through the flame.
Remove the rubber cap from the medicine pipette and replace it with a rubber or plastic tube. Blow into the tube so that air enters the flame just above the wick through the drawn end of the pipette. The flame will deviate to the side, its temperature will increase. Point the tongue at the sharpest part of the crayon. This area will become white-hot, the chalk here will turn into burnt (quicklime) CaO, and at the same time carbon dioxide will be released.
Do this operation several times with pieces of chalk, marble, and eggshells. Place the burned pieces in a clean tin. While they are cooling, place the largest piece in a saucer and drop some water on the place that was heated. There will be a hissing sound, all the water will be absorbed, and the baked area will crumble into powder. This powder is slaked lime Ca(OH)2.
Add more water and drop in the phenolphthalein solution. The water in the saucer will turn red; This means that slaked lime forms an alkaline solution.
When the burnt pieces have cooled, place them in a glass jar or bottle, fill with water, close the lid and shake - the water will become cloudy. You already know that we will now get lime water. Let the liquid settle and pour the clear solution into a clean bottle. Pour some limewater into a test tube - and you can use it to perform the previously described experiments with gases. Or you can do tricks, like turning “water” into “milk” or “water” into “blood.” You will find a description of such tricks in the section "Chemical tricks".
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Interesting experience in physics.
Interesting experiments for children
IN preparatory group conducting experiments should become the norm of life; they should be considered not as entertainment, but as a way to familiarize children with the world around them and the most effective way development of thought processes. Experiments allow you to combine all types of activities and all aspects of education, develop observation and inquisitiveness of the mind, develop the desire to understand the world, all cognitive abilities, the ability to invent, use standard solutions V difficult situations, create creative personality.
Some important tips:
1. Conduct experiments better in the morning when the child is full of strength and energy;
2. It is important for us not only to teach, but also to interest the child, to make him want to gain knowledge and do new experiments himself.
3. Explain to your child that you cannot taste unknown substances, no matter how beautiful and appetizing they look;
4. Don’t just show your child an interesting experience, but also explain in a language he understands why this happens;
5. Do not ignore your child’s questions - look for answers to them in books, reference books, and the Internet;
6. Where there is no danger, give the child more independence;
7. Invite your child to show his favorite experiments to his friends;
8. And most importantly: rejoice in your child’s successes, praise him and encourage his desire to learn. Only positive emotions can instill a love for new knowledge.
Experience No. 1. "Vanishing Chalk"
For a spectacular experience, we will need a small piece of chalk. Dip chalk into a glass of vinegar and see what happens. The chalk in the glass will begin to hiss, bubble, decrease in size and soon disappear completely.
Chalk is limestone; when it comes into contact with acetic acid, it turns into other substances, one of which is carbon dioxide, which is rapidly released in the form of bubbles.
Experience No. 2. "Erupting Volcano"
Required equipment:
Volcano:
- Make a cone from plasticine (you can take plasticine that has already been used once)
- Soda, 2 tbsp. spoons
Lava:
1. Vinegar 1/3 cup
2. Red paint, drop
3. A drop of liquid detergent to make the volcano foam better;
Experience No. 3. "Lava - lamp"
Needed: Salt, water, a glass of vegetable oil, several food coloring, large transparent glass.
Experiment: Fill a glass 2/3 with water, pour into the water vegetable oil. Oil will float on the surface. Add food coloring to water and oil. Then slowly add 1 teaspoon of salt.
Explanation: Oil is lighter than water, so it floats on the surface, but salt is heavier than oil, so when you add salt to a glass, the oil and salt begin to sink to the bottom. As the salt breaks down, it releases oil particles and they rise to the surface. Food coloring will help make the experience more visual and spectacular.
Experience No. 4. "Rain Clouds"
Children will love this simple activity that teaches them how to it's raining(schematically, of course): water first accumulates in the clouds and then spills onto the ground. This “experience” can be carried out both in a natural history lesson and in kindergarten V senior group and at home with children of all ages - it captivates everyone, and the children ask to repeat it again and again. So, stock up on shaving foam.
Fill the jar with water about 2/3 full. Squeeze the foam directly on top of the water until it looks like a cumulus cloud. Now use a pipette to drop colored water onto the foam (or better yet, trust your child to do this). And now all that remains is to watch how the colored water passes through the cloud and continues its journey to the bottom of the jar.
Experience No. 5. "Red Head Chemistry"
Place finely chopped cabbage in a glass and pour boiling water over it for 5 minutes. Strain the cabbage infusion through a cloth.
Pour into the other three glasses cold water. Add a little vinegar to one glass, a little soda to the other. Add the cabbage solution to a glass with vinegar - the water will turn red, add it to a glass of soda - the water will turn blue. Add the solution to a glass with clean water– the water will remain dark blue.
Experience No. 6. "Blow up the balloon"
Pour water into a bottle and dissolve a teaspoon of baking soda in it.
2. In a separate glass, mix lemon juice with vinegar and pour into a bottle.
3. Quickly place the balloon on the neck of the bottle, securing it with electrical tape. The ball will inflate. Baking soda and lemon juice mixed with vinegar reacts to release carbon dioxide, which inflates the balloon.
Experience No. 7. "Colored milk"
Needed: Whole milk, food coloring, liquid detergent, cotton swabs, plate.
Experience: Pour milk into a plate, add a few drops of different food colors. Then you need to take a cotton swab, dip it in the detergent and touch the swab to the very center of the plate with milk. The milk will begin to move and the colors will begin to mix.
Explanation: The detergent reacts with the fat molecules in the milk and causes them to move. This is why skim milk is not suitable for the experiment.
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