Download presentations for scientific and practical work indicators. Presentation - Research work “Natural indicators. Household tools analysis

Object under study

Initial color of the solution in a neutral medium

Acid staining

Alkaline dyeing

Kalanchoe (orange flowers)

pale yellow

yellow

pale yellow

Kalanchoe (red flowers)

maroon

pink

emerald green

Kalanchoe (pink flowers)

lilac

pink

green

Tulip (flowers are red)

maroon

dark orange

yellow-green

Tulip (leaves)

light green

without changes

green

Blue onion (husk)

Blue onion (bulb)

Yellow onion (husk)

Yellow onion (bulb)

Carrots (juice)

orange

Beetroot (juice)

Dandelion

yellow-green

light yellow

dark yellow

Black currant berries

Raspberries

Geranium (bright pink flowers)

hot pink

hot pink

light brown

Geranium (white flowers)

white

light yellow

white

Pansies (purple flowers)

violet

hot pink

emerald green

Pansies (yellow flowers with a brown center)

gray

bright green

Hot pink

Hibiscus

Slide 1

"Natural Indicators" RESEARCH WORK
The work was carried out by 11th grade pupils of the Municipal Autonomous Educational Institution Lyubokhonskaya Sredny comprehensive school named after twice Hero of the Soviet Union A.A. Golovachev Gunko Elena Alekseevna and teacher of biology and chemistry Kovalchuk Elena Viktorovna.
Municipal autonomous educational institution Lyubokhonsk secondary school named after twice Hero of the Soviet Union A.A. Golovachev.
smt. Lyubokhna, 2013

Slide 2

CONTENT
Chapter 1. Introduction Chapter 2. Main part 2.1. From the history of indicators. Classification of indicators. 2.2. Natural indicators. Biochemical role of natural indicators. Requirements for indicators. Chapter 3. Experimental part 3.1. Methods of manufacturing indicators from natural raw materials. 3.2. Research results table. 3.3. Determination of the medium of solutions of dishwashing detergents using plant indicators. 4. Conclusion. 5. Recommendations. 6. Literature.

Slide 3

1. Introduction
Indicators are substances that change their color depending on the reaction of the environment. The name "indicators" comes from the Latin word indicator, which means "pointer". In a chemical laboratory or at a factory, indicators in a visual form will tell you whether the chemical reaction has gone through to the end or not, it is enough to add one reagent to another, or you need to add more. When studying acids and bases in chemistry lessons, I learned that the juices of brightly colored berries, fruits and flowers have the properties of acid-base indicators, that is, they change their color when the acidity of the environment changes. I was interested in the question: what plants can be used as indicators? Can you prepare herbal indicator solutions yourself? And can the prepared indicator solutions be used to determine the reaction of the environment of dishwashing detergents in order to determine whether they have a negative effect on the skin of the hands. The relevance of the topic lies in the fact that the properties of plant objects can be used for application in various fields of science, such as, for example, chemistry.

Slide 4

1. Introduction
Purpose of the work: with the help of research, to prove the presence of natural indicators in plant objects, to study their properties, to determine with their help the reaction of the environment of solutions of detergents for dishes. Research objectives: 1) To study literary sources on the topic; 2) Investigate natural objects for the presence of indicators; 3) Study the properties of indicators contained in natural objects; 4) Conduct a study to determine the reaction of the environment of solutions of dishwashing detergents. Objects of research: berries of cherry, strawberry, mountain ash, blueberry, lingonberry, blackberry, chokeberry, black currant; leaves of red cabbage, parsley, black currant; fruits: beets; flowers: red rose, red geranium, multi-colored carnation. Research hypothesis: if plants change color in different environments, then they can be used as indicators Research methods: 1. Study of scientific literature on this issue 2. Qualitative analysis. 3. Observation.

Slide 5

2.1. From the history of indicators
The history of indicators begins in the 17th century. Back in 1640, botanists described heliotrope - a fragrant plant with dark purple flowers (see picture), from which the coloring matter was isolated. This dye, along with the juice of violets, has become widely used by chemists as an indicator. You can read about this in the works of the famous physicist and chemist of the 17th century Robert Boyle. In 1663 litmus was discovered - an aqueous infusion of lichen growing on the rocks of Scotland. Robert Boyle prepared an aqueous infusion of litmus lichen for his experiments. The bottle in which he kept the infusion was needed for hydrochloric acid. After pouring out the infusion, Boyle filled a bottle with acid and was surprised to find that the acid turned red. Having become interested in this, Boyle added a few drops of litmus infusion to an aqueous solution of sodium hydroxide for testing and found that in an alkaline medium the litmus turns blue. This is how the first indicator for the detection of acids and bases was discovered, named after the lichen by the litmus. Phenolphthalein, which is used in the form of an alcohol solution, acquires a crimson color in an alkaline medium, and is colorless in a neutral and acidic medium. The synthesis of phenolphthalein was first carried out in 1871 by the German chemist Adolph von Bayer, the future Nobel Prize laureate. As for the methyl orange indicator, discovered in 1887, it is indeed orange in a neutral environment. In acids, its color becomes pink-raspberry, and in alkalis - yellow.

Slide 6

2.1. Classification of indicators
One of the most common are acid-base indicators, which change color depending on the acidity of the solution. This happens because indicator molecules have different structures in acidic and alkaline environments. An example is the well-known indicator phenolphthalein. In an acidic medium, this compound is in the form of undissociated molecules and the solution is colorless, and in an alkaline medium it is in the form of ions and the solution has a crimson color. In addition to acid-base, other types of indicators are also used. Redox indicators change their color depending on the presence of an oxidizing agent or a reducing agent in the solution. Such indicators are substances that themselves undergo oxidation or reduction, and the oxidized and reduced forms have different colors. For example, the oxidized form of diphenylamine is violet in color, while the reduced form is colorless. Complexometric indicators are widespread - substances that form colored complex compounds with metal ions. Some substances are adsorbed on the surface of the sediment, changing its color; such indicators are called adsorption indicators. When determining the environment of turbid or colored solutions, in which it is almost impossible to notice a change in the color of conventional acid-base indicators, fluorescent indicators are used. They glow (fluoresce) in a different color depending on the pH of the solution. It is important that the glow of the indicator does not depend on the transparency and its own color of the solution. Often, universal indicators are used - a mixture of several individual indicators, selected so that their solution alternately changes color, passing all the colors of the rainbow when the acidity of the solution changes in a wide pH range (for example, from 1 to 11). Strips of paper are often impregnated with a solution of the universal indicator, which allow one to quickly (although with not very high accuracy) determine the pH of the solution being analyzed by comparing the color of the strip moistened with the solution with a standard color scale.

Slide 7

2.2 Natural indicators
If there are no real chemical indicators, then indicators isolated from natural raw materials can be successfully used to determine the medium of solutions. The starting material can be geranium flowers, peony or mallow petals, iris, dark tulips or pansies, as well as raspberries, blueberries, chokeberries, cherry juices, currants, grapes, buckthorn and bird cherry fruits. These natural indicators contain colored substances (pigments) that can change their color in response to a particular effect and, getting into an acidic or alkaline environment, they visually signal this. These pigments are, first of all, anthocyanins: in a neutral medium they acquire a purple color, in an acidic medium - a red color, in an alkaline medium - a green-yellow color. It is anthocyanins that impart various shades of pink, red, blue and purple to many flowers, fruits and autumn leaves. This color often depends on the pH of the cell content, and therefore can change with ripening of fruits, flowering of flowers and wilting of leaves Anthocyanins are unstable compounds; plant cells usually contain several different anthocyanins, and their manifestation is associated with the chemical composition of the soil and the age of the plant. Ordinary tea is also an indicator. If lemon juice is dropped into a glass of strong tea or a few crystals of citric acid are dissolved, the tea will immediately become lighter. If you dissolve baking soda in tea, the solution will darken (you should not drink such tea, of course). Hibiscus tea produces much brighter colors. An indicator is also ordinary ink, which, under the influence of acid, changes its color from violet to green, and again acquires a violet color when the acid is neutralized with alkali.

Slide 8

2.2 Biochemical role of indicators
Entering the human body with fruits and vegetables, anthocyanins exhibit an effect similar to vitamin P; they maintain a normal state of blood pressure and blood vessels, preventing internal hemorrhages. Anthocyanins are required by brain cells, improve memory. Anthocyanins are powerful antioxidants that are 50 times stronger than vitamin C. Many studies have confirmed the benefits of anthocyanins for vision. The highest concentration of anthocyanins is found in blueberries. Therefore, preparations containing blueberries are most in demand in medicine.

Slide 9

2.2 Requirements for indicators
For any substance to serve as an indicator, it must meet the following necessary conditions: 1) must be a weak acid or weak base; 2) its molecules and ions must have different colors; 3) their color must be extremely intense in order to be noticeable when a small amount of indicator is added to the test solution. Natural indicators have a serious drawback: their decoctions deteriorate rather quickly - they turn sour or moldy (alcohol solutions are more stable). Another drawback is the too wide range of color change. In this case, it is difficult or impossible to distinguish, for example, a neutral medium from a weakly acidic or slightly alkaline from a strongly alkaline one.

Slide 10

3.1. Own research
During the summer I prepared indicators. Plants were used as the starting material. Extracts were obtained from all collected plants one by one. For this, the fruits were crushed, poured with water and boiled for 1-2 minutes. Then the solution was cooled and filtered. The resulting filtrate was diluted with alcohol at the rate of two volumes of the filtrate and one volume of alcohol in order to protect it from deterioration. I prepared extracts from petals of flowers and leaves in the same way. Chemical vessels were used to prepare the indicators: test tubes, beakers, pipettes, funnels, filter paper, and a water bath. Distilled water, solutions with acidic and alkaline media were also required. Table vinegar (9%) served as an acidic solution, and a solution of washing (soda ash) soda served as an alkaline solution. The prepared plant indicators were tested when exposed to acidic and alkaline solutions. Fruits, petals, leaves, flowers of the following plants were examined: cherry, strawberry, blueberry, lingonberry, blackberry, chokeberry, beet, black currant, carnation, red rose, red cabbage, red geranium, parsley, mountain ash. The research results are listed in Table 1.

Slide 11

3.2. Results of the study of indicator plants

TABLE 1:
RAW MATERIALS FOR INDICATOR PREPARATION NATURAL INDICATOR COLOR SOLUTION COLOR SOLUTION COLOR
RAW MATERIALS FOR PREPARING INDICATORS NATURAL COLOR OF THE INDICATOR in an acidic medium (pH> 7) in an alkaline medium (pH Cherry (berries) Dark red Bright red Dirty green
Strawberry (berries) Pink Orange Light brown
Rowan (berries) Red Raspberry Pink
Blueberries (berries) Light purple Violet Dirty green
Lingonberry (berries) Dark red Yellow Orange
Blackberries (berries) Dark purple Red Brown
Chokeberry (berries) Burgundy Red Dirty green
Beetroot (fruit) Ruby Bright red Yellow
Red cabbage (leaves) Dark purple Green Lilac
Black currant (berries) Burgundy Red Green
Black currant (leaves) Yellow-green Yellow Brown
Parsley (leaves) Yellow-green Light brown Yellow
Red rose (flowers) Pink Burgundy Bright red
Carnation (flowers) Brown Pale pink Yellow
Red geranium (flowers) Red Orange Light brown

Slide 12

3.3. Determination of the medium of solutions of dishwashing detergents using vegetable indicators

In biology lessons, I learned that the outer surface of the epidermis is covered with a microscopically thin layer - an acid mantle. Many biochemical processes take place in the epidermis. As a result, acids are formed - lactic, citric and others. Plus to this: sebum and sweat. All this constitutes the acidic mantle of the skin. Therefore, normal skin is acidic, with skin pH averaging 5.5. When using alkaline dishwashing detergents, we disrupt the normal acidic environment of the skin of the hands. To protect the skin of the hands from negative impact detergents for dishes should have a pH value corresponding to the pH value of the acid mantle of the epidermis. With the help of prepared solutions of natural indicators, I checked what kind of environment different dish detergents have.

Slide 13

3.3. Reaction of the medium in dishwashing detergent solutions

TABLE 2:
No. Detergent for dishes Herbal indicator Color of indicator Solution medium
1 "Myth" Red cabbage broth Pale green Weakly alkaline
2 "Fairy" Red cabbage broth Green Alkaline
3 "AOS" Strawberry decoction Pale yellow Weakly alkaline
4 "Pril" Aronia berry decoction Pale pink Slightly acidic

Slide 14

4. Conclusion

After my research work, I came to the following conclusions: - many natural plants have the properties of acid-base indicators, capable of changing their color depending on the environment in which they enter; - solutions of herbal indicators can be used, for example, as acid-base indicators for determining the medium of solutions of dishwashing detergents at home; - homemade indicators from natural raw materials can be used in chemistry lessons in schools, if there is a problem of providing the school with chemical reagents. According to the results of the study, the indicator properties of the objects under study were proved. Moreover, the following pattern is observed here - all these natural objects in an acidic environment are predominantly colored red, and in an alkaline environment - in green-yellow. And this proves that they do contain anthocyanins. This study showed that in nature there are such plant objects that change their color depending on the acidity of the environment. Therefore, we can call them natural indicators.

Slide 15

1) Natural indicators can be used in chemistry lessons, elective courses. 2) Plant indicators can be used in everyday life. Beet juice in an acidic environment changes its ruby ​​color to bright red, and in an alkaline environment - to yellow. Knowing the properties of beetroot juice, you can make the color of the borscht bright. To do this, add a little vinegar or citric acid to the borscht. 3) To determine the composition of drugs that are used for treatment, you can use natural indicators. Many medications are acids, salts and bases. Having studied their properties, you can protect yourself. For example, aspirin (acetylsalicylic acid), many vitamins should not be taken on an empty stomach, as the acids in their composition will damage the stomach lining. 4) The results of research work can be used to determine the pH (pH) of various solutions, for example, dairy products, broths, lemonade and others, as well as to determine the acidity of the soil, since on the same soil, depending on its acidity, one species plants can produce high yields, while others will be oppressed. 5) Detergents for dishes "Myth", "Fairy", "AOS" have an alkaline and slightly alkaline environment and when using them, rubber gloves must be used to protect the skin of the hands from negative effects, since the alkaline environment destroys the acid mantle of the epidermis; 6) In the poem of the famous English poet R.Kipling "Blue Roses", there are the following lines: Somehow, dear, I brought a whole heap of red roses. She did not take - and in tears, blue, find her roses. I shouldn't have traveled all over the world - there are no blue roses under the sun. Of course, there are no raspberry cornflowers and blue lilies of the valley, but you can give the flowers a fantastic color. Pour concentrated ammonia into a cylinder and place a red rose flower. After a few minutes, a color change can be observed. When interacting with vapors of ammonia, the color of the red rose turns blue.

Slide 16

6. References

1.Alikberova L.Yu. Entertaining chemistry. - M .: AST-PRESS, 2002.2. Alikberova L.Yu. Entertaining chemistry. A book for students, teachers and parents. - M .: AST-PRESS, 1999.3. Oganesyan E.T. A guide to chemistry for university applicants. - M .: graduate School, 1998 4. Savina L.A. I get to know the world. Children's encyclopedia. Chemistry. - M .: AST, 1996. 5. New encyclopedic dictionary. - M .: Great Russian Encyclopedia. Rinol Classic, 2000. 6. Encyclopedic Dictionary of a Young Chemist. - M .: Pedagogika, 1982.7.Stepin B.D., Alikberova L.Yu. Entertaining tasks and spectacular chemistry experiments. - M .: Bustard, 2002.8. Internet resources. 9. Pilipenko A.T. "Handbook of Elementary Chemistry". Kiev "Naukova Dumka". 1973 Pages 164 -167. 10. Baykova V.M. "Chemistry after school". 1976 P. 90-95. 11. Scientific - practical journal "Chemistry for schoolchildren" No. 4 2007. p.60 12. Educational-methodical newspaper for teachers of chemistry "September 1", No. 22, 2007. 13. Balaev I.I. "Home experiment in chemistry." 14. Nazarova T.S., Grabetsky A.A. "Chemical experiment at school", Moscow. 1987 15. Information from the website alchemic.ru "Good advice".

"Secondary school No. 2 in Zhirnovsk"

Volgograd region

Research work in chemistry on the topic:

"Indicators in our life"

Completed: student 8 "A" class MOU "Secondary school No. 2 in Zhirnovsk"

Danina Maria Vitalievna (14 years old)

Head: chemistry teacher Anastasia Sergeevna Aleshkova

Zhirnovsk, 2015

Introduction ………………………………………………………………… ..3 - 4

1. 
   Indicators ………………………………………………………. ………5
   1. 
      Chemical indicators. The history of the formation of indicators. ... 5 - 7
   2. 
      Natural indicators. Characteristics and classification ... ... 7 - 9
2. 
   Experimental part …………………………………………… .10
   1. 
      Research methodology …………………………………………… ... 10
   2. 
      Results and discussion ……………………………………… 10 - 12

Conclusion ……………………………………………………………………… 14

References ………………………………………………………… ... 15

Introduction

Nature is an amazing creation of the Universe. The natural world is beautiful, mysterious and complex. This world is rich in a variety of fauna and flora.The plant kingdom surprises us with its variety of color shades. The color palette is so varied that it is impossible to say how many flowers and their shades exist in the plant world. Thus, the question arises - what does the color of certain plants depend on? What is the structure of plants? What do they contain? And what are their properties? The further we plunge into the world of plants, the more and more we ask ourselves other questions. It turns out that the color of plants is determined by the chemical composition of the cellular content of each plant. Or rather, the so-called bioflavonoids are to blame. These are natural chemical compounds that give a certain color shade and properties to any plant. Therefore, there are many bioflavonoids. These include anthocyanins, xanthophylls, carotenoids, catechins, flavonols, flavonones, and others. The benefits of many plants are undeniable. Since ancient times, people have used plants as medicines... Therefore, it is not for nothing that folk medicine arose, based on the unique and medicinal properties of plants.

Why we have chosen this topic.

First, we are interested in the properties of plant objects.

Second, what is their role in a science like chemistry?

How are their indicator properties determined?

And, thirdly, how you can use their properties for medicinal purposes.

Therefore, we will consider flavonoids such as anthocyanins. Because they are ideal candidates for our research.

Relevance of the topic lies in the fact that today more and more interest is in the properties of plant objects for their application and use in various fields of science, such as chemistry, biology and medicine.

purpose of work: using research to prove the presence of natural indicators - anthocyanin pigments in plant objects and to study their properties.

Research objectives:

1) Analyze literature on plant physiology and biochemistry of indicators

2) Explore natural objects for the presence of indicators - anthocyanins;

3) To prove the indicator properties of plant pigments - anthocyanins;

4) Reveal the significance and biochemical role of natural objects containing anthocyanins.
Object research is: lemon peel, carrot roots, beetroot, black tea, onion husks, flowers of decabris, geranium, gerbera and violets.

1. 
   Indicators
   1. 
      Chemical indicators: history of indicator formation

Chemical indicators include such as acid-base, universal, redox, adsorption, fluorescent, complexometric and others.

Also, indicators can be found among natural objects. The pigments of many plants can change color depending on the acidity of the cell sap. Consequently, pigments are indicators that can be used to study the acidity of other solutions. The common name for such plant pigments is flavonoids. This group includes the so-called anthocyanins, which have good indicator properties.

The most famous plant acid-base indicator used in chemistry is litmus. It was already known in Ancient Egypt and Ancient Rome, where it was used as a purple paint substitute for expensive purple. Litmus was prepared from special types of lichens. The crushed lichens were moistened, and then ash and soda were added to this mixture. The prepared mixture was placed in wooden barrels, urine was added and kept for a long time. Gradually the solution became dark blue. It was evaporated and used in this form for dyeing fabrics.

Later litmus was discovered in 1663. It was an aqueous solution of lichen growing on rocks in Scotland.

The following historical fact is also known:

“In the laboratory of the famous English scientist physicist and chemist Robert Boyle, as usual, hard work was in full swing: candles were burning, various substances were heated in retorts. The gardener entered Boyle's study and placed a basket of deep purple violets in the corner. At this time, Boyle was going to conduct an experiment on the production of sulfuric acid. Fascinated by the beauty and aroma of violets, the scientist, taking a bunch with him, went to the laboratory. The lab technician told Boyle that two bottles of hydrochloric acid were delivered from Amsterdam yesterday. Boyle wanted to look at the acid, and to help the technician pour the acid, he put the violets on the table. Then, before heading to the office, he took his bouquet and noticed that the violets were slightly smoking from the spray of acid on them. To rinse the flowers, he dipped them into a glass of water. After a while, he glanced at the glass with violets, and a miracle happened: the dark purple violets turned red. Naturally, the scientist began research. He found that other acids also stain violet petals red. He thought that if he prepared an infusion from the petals and added it to the solution under study, he would be able to find out if it was sour or not. Boyle began to prepare infusions from other plants: medicinal herbs, tree bark, plant roots, etc. However, the most interesting was the purple infusion obtained from litmus lichen. Acids changed its color to red, and alkalis to blue.

Boyle ordered to soak paper with this infusion and then dry it. This is how the first litmus paper was created, which is available in any chemical laboratory. Thus, one of the first substances was discovered, which Boyle already then called “ indicator. "

Robert Boyle prepared an aqueous solution of litmus lichen for his experiments. The bottle in which he kept the infusion was needed for hydrochloric acid. After pouring out the infusion, Boyle filled a bottle with acid and was surprised to find that the acid turned red. Intrigued by this phenomenon, Boyle added a few drops to an aqueous solution of sodium hydroxide for a test and found that in an alkaline medium the litmus turns blue. So the first indicator for the detection of acids and alkalis was discovered, named after the lichen by the litmus. Since then, this indicator has been one of the indispensable indicators in various research in the field of chemistry. "

Acid-base indicators.

Most often, acid-base indicators are used in laboratories. These include phenolphthalein, litmus, methyl orange, bromothymol blue, and others.

Acid-base indicators are organic compounds that can change color in solution when acidity changes. They change color within fairly narrow pH ranges. There are many such indicators, and each of them has its own field of application.

Such indicators are among the most stable and in demand in chemistry laboratories.

1. 
   Natural indicators. Characteristics and classification.

The pigments of many plants can change color depending on the acidity of the cell sap. Therefore, plant pigments are indicators that can be used to study the acidity of other solutions. The general name for natural pigments is flavonoids. This group includes carotenoids, xanthophylls, anthocyanins, respectively, determining the yellow, orange, red, blue, purple color of plants.

Anthocyanins are natural pigments from the flavonoid group.

A large number of objects are known to be rich in anthocyanins. These are raspberries, strawberries, strawberries, cherries, plums, red cabbage, black grapes, beets, blueberries, blueberries, cranberries and many others.

Anthocyanins give the fruits purple, blue, brown, red or orange colors. This variety is due to the fact that the color changes depending on the balance of acids and alkalis.

The structure of anthocyanins was established in 1913 by the German biochemist R. Willstatter. The first chemical synthesis was carried out in 1928 by the English chemist R. Robinson. The variety of colors is explained not only by the peculiarities of their structure, but also by the formation of complexes with ionic K (purple salt), Mg and Ca (blue salt), as well as adsorption on polysaccharides. The formation of anthocyanins is favored by low temperatures and intense lighting.

Anthocyanins have good indicator properties: in a neutral medium they acquire a purple color, in an acidic medium - a red color, in an alkaline medium - a green-yellow color.

Indicators allow you to quickly and accurately monitor the composition of liquid media, monitor changes in their composition or the course of a chemical reaction.

As already mentioned, the common name for all natural pigments, natural indicators, is flavonoids.

Flavonoids are heterocyclic compounds. Depending on the structure and oxidation state, they are divided into anthocyanins, catechins, flavonols, flavonones, carotenoids, xanthophylls, etc. They are found in plants in a free state and in the form of glycosides (with the exception of catechins).

Anthocyanins are bioflavonoids that give the fruit purple, blue, brown, red color.

Entering the human body with fruits and vegetables, anthocyanins exhibit an effect similar to vitamin P; they maintain a normal state of blood pressure and blood vessels, preventing internal hemorrhages. Anthocyanins are required by brain cells, improve memory.

Anthocyanins are powerful antioxidants that are 50 times stronger than vitamin C. Many studies have confirmed the benefits of anthocyanins for vision. The highest concentration of anthocyanins is found in blueberries. Therefore, preparations containing blueberries are most in demand in medicine.

Since anthocyanins have good indicator properties, they can be used as indicators for identifying acidic, alkaline or neutral environments, both in chemistry and in everyday life.

1. 
   experimental part
   1. 
      Research methodology.

Reagents: 1) water

2) 5% - hydrochloric acid

3) 5% sodium hydroxide

Equipment and utensils: mortar, pestle, test tubes, pipette, tripod

Study material: plant objects

1. 
   Results and discussion

Table 2.1

Change in the color of natural indicators in an acid - alkaline environment

As a result, we found that the color of plant pigments under the action of acids and alkalis changes depending on the type of plant and the color of the original pigments. For example, carotenoids in common carrots practically do not change color when acidity changes. And since the studied pigments of onion peel and lemon peel are very similar in color to the pigments of carrots and, like carrots, did not change color with a change in acidity, we can assume that their color is also due to carotenoids. Carotenoids are unsuitable as acid-base indicators.

Plants containing anthocyanins changed their color under the action of acids and alkalis. For example, indoor violet, indoor geranium, Decembris, gerbera, beets discolored in an alkaline environment, and acquired a raspberry color in an acidic one. Ordinary tea can also be used at home as a natural indicator. Have you noticed that tea with lemon is much lighter than without lemon. In an acidic environment, it becomes discolored, and in an alkaline environment it becomes darker.

conclusions

1. 
   Analyzed the literature on the biochemistry of indicators
2. 
   Indicator properties of the studied objects are proved.
3. 
   A regularity has been revealed: all these natural objects in an acidic medium are predominantly colored red, and in an alkaline medium they become discolored. Which proves the presence of anthocyanins.

Conclusion

As a result of this research work, we have proved that among natural objects there are a large number of natural indicators that can be used and applied both in everyday life and in chemistry for various other studies.

Anthocyanins are also often used in medicine due to their unique properties. Anthocyanins are of immense biochemical importance. Anthocyanins are powerful antioxidants that neutralize free radicals, which in turn have a detrimental effect on our body. Thus, anthocyanins are guarantors of a long and healthy life cells, which means they extend our life as well. Many studies have confirmed the benefits of anthocyanins for vision. They also help lower blood sugar levels. This is especially true for those people who are sick with diabetes. To get all these benefits, scientists advise to eat only half a glass of blueberries a day - fresh or frozen. Therefore, preparations containing blueberries are most in demand in medicine.

Bibliography:

1. 
   Vetchinsky K.M. Vegetable indicator), Moscow: Education, 2002, 256 p.
2. 
   Vronsky V.A. Vegetable indicator. - SPb .: Parity, 2002 .-- 253p.
3. 
   Galin G.A. Plants help geologists. - M .: Nauka, 1989 .-- 99p.
4. 
   Zatser L.M. On the use of indicator plants in chemistry. - M .: Nauka, 2000 .-- 253p.
5. 
   Leenson I.A. Entertaining chemistry: grades 8-11. - M .: Education, 2001 .-- 102s.
6. 
   Sokolov V.A. Natural Dyes), Moscow: Enlightenment, 1997.
7. 
   Chemistry in School magazine # 2, # 8 - 2002.

Raw materials for cooking

indicator

Natural indicator color

Coloring in

sour

environment

Coloring in

alkaline environment

Raspberries

Brown

Brown

Dark brown

Chokeberry berries

Red brown

Pale pink

Dark green

Strawberries

Red-orange

Orange

Dark yellow

Buckthorn bark

Dark yellow

Red cabbage

Blue violet

Mallow petals

Dark green

Raw materials for cooking

indicator

Natural indicator color

Coloring in

sour

environment

Coloring in

alkaline environment

Raspberries

Brown

Brown

Dark brown

Chokeberry berries

Red brown

Pale pink

Dark green

Strawberries

Red-orange

Orange

Dark yellow

Buckthorn bark

Dark yellow

Red cabbage

Blue violet

Mallow petals

Dark green