Design and experimental activities in the senior group on the topic: Milk. Turning milk into plastic

All things in the world are made of molecules (we will not talk about other smallest particles yet). There are various connections between them. If they are violated, interesting reactions can occur, sometimes very bright and spectacular. That's what we're going to talk about today. And the kid will become the star of any children's holiday if he learns to do this beautiful chemical experiment.

For an experiment for children at home, you will need: whole milk (required!), Food colors of different colors, any liquid detergent, cotton swabs, pipette, plate. And, of course, a camera to capture a colorful masterpiece.

The children have gathered, we begin the experiment:

1. Dilute dyes - red, green, blue, yellow - in small jars. Pour milk into a bowl. It should be at room temperature. So if the milk was in the refrigerator, it must be set in advance.

2. We collect each dye with a pipette, carefully drip it into the center, onto the surface of the milk. We must strive to ensure that the droplet is small, like a dot. It turns out four points.

3. Then we take a cotton swab, dip it in detergent, touch it to the center of the plate with milk and hold it there for literally 10-15 seconds. You don't need to mix. We remove the wand.

4. And then a miracle will happen! The milk itself will begin to move, and the colors will mix. A real salute or a storm of flowers in a bowl! We take photos for memory. If you wish, you can experiment further by adding more dye and drawing with sticks.

Explanation of experience for children

Milk, in addition to water, consists of molecules of various types: fats, proteins, carbohydrates, vitamins and minerals. Proteins and fat are very sensitive to changes in the solution, in this case milk. The secret of this trick lies precisely in a drop of detergent, which weakens the chemical bonds that hold fats and proteins in solution, and reduces the surface tension in milk. There is a violent chemical reaction, which we can observe thanks to food coloring. As soon as the detergent mixes evenly with milk (partially dissolves, partially attaches to fat molecules), the reaction subsides and stops.

With this amazing experience in chemistry, You will learn how to transform an ordinary homemade milk into a magical mixture, in just a few minutes.

To complete the experience you will need:

Whole milk (skimmed milk will not work)
Two different food colors
Dishwashing liquid
Small pie pan

Time to complete the experiment:

Approximately 10-15 minutes

Let's start the experiment:

Take the milk and pour it into a cake pan, let the milk come to room temperature.
Add a few different drops of food coloring to the milk.
Now take your detergent and add it to the milk and dye mixture.
Watch!

Note:

You must definitely wait until the milk has warmed up to room temperature, otherwise Experience "Magic Milk" will not show the result that it should show.

Result:

Detergent breaks down the fat in the milk and makes the food coloring flutter in the milk, thus making for some neat designs.

What makes milk move?

Milk, in addition to water, contains vitamins, minerals, proteins and tiny particles of fat, as if suspended in a solution. Proteins and fat are very sensitive to changes in the solution, in this case milk. The secret of this trick is precisely in a drop of detergent or liquid soap, which weaken the chemical bonds that hold fats and proteins in solution, and reduce the surface tension in milk. There is a violent chemical reaction, which we can observe thanks to food coloring. As soon as the detergent mixes evenly with milk (partially dissolves, partially attaches to fat molecules), the reaction subsides and stops. That is the secret of this entertaining chemical experiment. To repeat the color explosion in milk, simply add another drop of detergent.

Young chemists

With younger children, you can limit yourself to drawing and discussing who sees what in such milk drawings. Surely this experience with milk, food coloring and detergent will really fire their imaginations. Keep your camera nearby as the drawings will change all the time.

With older children, you can really experiment: try this experiment with different liquids, leaving dyes and detergent unchanged (of the same manufacturer in the same amount). Try this experience with water, with skim milk, with milk of different fat content, with cream. Take a picture of your results and compare. This is the first step towards real science!

And here's what that experience might look like

Article for the competition "bio/mol/text": We almost always believe what is written on the label of food products. The article is devoted to the identification of impurities in milk and dairy products and the determination of their quality at home. With the help of experiments that even a child can handle!

The editors draw the attention of readers to the fact that this wonderful article was written by a 5th grade student, so some simplifications in it are inevitable. But the “biomolecule” still considered it necessary to correct a couple of inaccuracies :-).

The sponsor of the nomination is , a project that brings together professionals and enthusiasts in the field of biology and biotechnology.

The general sponsor of the competition, according to our crowdfunding, was an entrepreneur Konstantin Sinyushin, for which he has a huge human respect!

The Audience Choice Award was sponsored by Atlas.

We decided to study the milk and dairy products we consume and develop a "home laboratory" to determine the qualitative composition of milk and dairy products. The main objectives of the study:

to study the role of milk and dairy products in healthy human nutrition;
to identify empirically the presence of impurities (starch, soda, chalk, water) in milk and dairy products;
develop practical recommendations for determining the qualitative composition of milk and dairy products at home.

During the study, it was assumed that the composition of milk and dairy products may contain impurities that are not declared by the manufacturer and not provided for by the standard.

Milk is a valuable product

The role of milk in healthy human nutrition. Types of milk

Milk is one of the most valuable food products. Milk is superior in value to many other products. Just two glasses of milk a day is enough to provide 30% of an adult's need for protein, 50% for potassium, and 75% for calcium and phosphorus.

In Russia, the norm for milk consumption per person per year is 325 kg. It is this amount of milk that meets the requirements of a healthy diet. In fact, Russians consume an average of 248 kg, and residents of the Ulyanovsk region - only 240 kg of milk per year.

The most valuable is whole milk- milk without the addition of any substances, including water, with natural fat content, which is different for each animal (from 2.6 to 6%). That is, they milked a cow or a goat - and received this very “correct” milk.

normalized milk- this is a product obtained from milk and brought to the required percentage of fat content by mixing this product with milk of a different fat content or with skimmed milk.

Powdered milk obtained by drying ordinary cow's milk at a very high temperature (about 170 ° C).

Reconstituted milk is milk obtained by adding water to milk powder. That is, they took powdered milk, diluted it with water - and here it is, reconstituted milk. In some countries, such milk is prohibited for sale, because when dried, potentially harmful substances are formed in it (oxysterols, which provoke the development of atherosclerosis in large quantities), beneficial microorganisms die, and vitamins are destroyed. In Russia, such milk should be called "milk drink", not milk.

Types of milk processing

On the way from the cow to the consumer, the milk is processed to kill microbes and increase shelf life.

It is better to use pasteurized milk for food, as it retains more vitamins and beneficial bacteria.

Starch and other impurities in milk and dairy products

Modern stores have a huge variety of dairy products. These are yoghurts, cottage cheese and curds, ice cream ...

But to maintain your health, it is important to eat quality dairy products. It's no secret that many manufacturers add various food additives to them - for example, starch, soda, chalk, or simply dilute milk with water. To prevent the milk from sour for a long time, antibiotics are added to it, which inhibit the growth of unwanted bacteria, but at the same time destroy the beneficial ones.

Starch is mixed in to thicken milk, cream, sour cream and yogurt. Starch is natural, which is found in the cells of vegetables, fruits, cereals, nuts and is safe for the human body. But isolated in its pure form - in the form of a white powder - it is already less harmless: in the gastrointestinal tract it is more easily broken down to glucose and increases insulin levels faster. And there is a modified starch (chemically, not genetically, modified), the properties of which depend on the type of modification: for example, resistant starch (E1442) is even useful - it stimulates the growth of beneficial bacteria in the intestines. In Russia and other countries, it is allowed to use several types of modified starch, but it is better to avoid excessive consumption of any starches.

Figure 6. Experiments in the laboratory at the Ulyanovsk State Agricultural Academy

Three types of milk for baby food were used for the experiments:

Milk "Krepysh", sterilized, 3.2%.
Milk "Krepysh", sterilized, fortified, 3.2%.
Milk "Agusha", sterilized, 2.5%.

2 ml of all three milk samples were poured into a Petri dish. Added 4 ml each (i.e. twice as much) of alcohol (tinted with "green" for clarity). Milk protein casein tends to coagulate under the influence of alcohol. If the product is of high quality, then the liquid will almost instantly (within 3-7 seconds) turn into flakes. The more water added to the product, the longer this protein will fold - the longer it takes for the appearance of flakes (Fig. 7).

Figure 7. Study of the reaction of milk protein (casein) to alcohol

The study was carried out in triplicate. The results of the experiments were as follows:

Flakes formed on average after 4–6 seconds.
Flakes formed on average after 2–3 seconds.
Flakes did not form in any of the three samples.

Conclusion: the milk sample under No. 3 has a reduced protein content, possibly diluted with water. This is Agusha milk, sterilized, 2.5%.

Souring test

We poured milk into test tubes of 5 ml (Fig. 8). The samples were allowed to stand overnight at room temperature. The pure product should turn sour, forming a layer of cream on top. If there is no cream, the milk has been defatted. If the milk does not turn sour, then there is something extra in it (perhaps an antibiotic).

The study was carried out in triplicate. The results were as follows:

The layer of cream averaged 1.5 mm per 5 ml of milk.
The layer of cream averaged 1 mm per 5 ml of milk.
Cream was not formed in any of the three milk samples, milk did not turn sour during the day.

Figure 8 Settling test

Conclusions:

Milk Sample #2 contains less fat than Sample #1, even though the label claims the same fat content of 3.2.
Milk sample #3 contains impurities that prevent it from turning sour - possibly antibiotics or preservatives.

Detection of soda and chalk impurities in milk

To prevent milk from spoiling for a long time, manufacturers add chalk or soda to it. These impurities in milk (unless the manufacturer has normalized the pH level of milk after their addition) can be detected by adding acetic acid - milk will instantly turn sour (curdled), and the appearance of foam will indicate the presence of chalk or soda in milk (Fig. 9).

Figure 9. Detection of soda and chalk impurities in milk

In the course of the experiment, when acetic acid was added, the milk curdled in all three samples (Fig. 10).

Figure 10. Results of detecting soda and chalk impurities in milk

Conclusion: milk samples do not contain impurities of chalk and soda.

To verify the correctness of the experiment, we added a small amount of soda to the milk, and then acetic acid. Foam formed (Fig. 11). The presence of chalk in milk also makes itself felt foam.

Figure 11. Evaluation of the reliability of the experiment on the detection of soda and chalk impurities in milk

Conclusion: the results of the experiment on the detection of impurities of soda and chalk in milk can be considered quite reliable. It should be noted that the reliability of the experiment will be absolute if, after the addition of impurities, the milk pH is brought to the initial level.

Determination of the presence of impurities of soda and chalk in milk in the laboratory

Indicator strips were taken to detect soda in milk. These strips were dipped into milk, and by comparing the color of the strip with the reference scale, the acidity of the milk was determined (Fig. 12).

Figure 12. Determination of the presence of impurities of soda and chalk in milk in the laboratory

The norm is 6-7 units. The results of the experiment showed the following:

sample #1 - pH=7 (test strip changed color to slightly orange);
samples #2 and #3 - pH=6 (test strip changed color to bright yellow).

Conclusion: Soda impurities were not found in any of the samples.

The reliability of the experiment was checked by adding soda to milk. Having dipped the test strip in milk with soda, we saw a color change to green, which corresponds to an alkaline environment (pH=9) (Fig. 13).

Figure 13. Checking the purity of the experiment to detect impurities of soda and chalk in milk

Conclusion: the results of the experiment on the detection of impurities of soda and chalk in milk can be considered quite reliable. As in the previous experiment, the purity of the experiment will be absolute if, after the addition of impurities, the milk pH is brought to the initial level.

Conclusion

In the course of the experiments, our hypothesis was confirmed. In the composition of individual samples of milk and dairy products, impurities were found that were not declared by the manufacturer.

We have developed a set "Home milk laboratory" for the examination of dairy products at home, which consists of reagents and instructions for use.

Detection of starch impurities in milk is carried out by adding 2–3 drops of iodine to milk (2 ml). The presence of impurities is indicated by a change in the color of milk to blue or purple.

To detect low protein content in milk, add 4 ml of alcohol to 2 ml of milk. The reaction is taken into account by the curdling speed. High protein milk curdles instantly. The reason for the low protein content in milk may be dilution with water.

To identify milk with a reduced content of milk fat, a settling test is carried out during the day at room temperature. The reaction is taken into account by the degree of souring of milk. If there is no cream layer, then the milk is skimmed. When the souring process is slowed down or absent, antibiotics or preservatives are added to the milk.

To detect chalk and soda impurities in milk, acetic acid (2–3 drops) is added to 2.5 ml of the sample. The appearance of foam indicates the presence of impurities.

Another way to detect soda in milk is based on the use of indicator strips (sold at a pharmacy). The reaction is detected by changing the color of the test strip and comparing it with the reference scale. The acidity of 6-7 units is considered the norm. Exceeding the norm means the presence of soda impurities in milk.

The developed set "Home laboratory of milk" can be used in life by a wide range of people.

I express my gratitude to my mentors for their help in conducting research and preparing materials: the teacher of the Oktyabrsky Rural Lyceum Loktina Raisa Vasilievna and the scientific consultant Yulia Borisovna Vasilyeva, Candidate of Veterinary Sciences, Associate Professor of the Department of Microbiology, Virology, Epizootology and Veterinary and Sanitary Expertise of the Federal State Budgetary Educational Institution of Higher Education Ulyanovsk State Agricultural Academy.»;;

How to determine the quality of milk. Website "I'm 30".

research project

"Milk and Dairy Products"

Introduction

Relevance.

Milk is an essential and indispensable product of baby food. Due to its chemical composition and biological properties, it has an exceptional place among animal products used in children's nutrition.

Unfortunately, not all children are happy to drink milk and eat milk-based dishes. I love drinking milk. And I wanted to reveal the valuable qualities of milk and show how dairy products are obtained. Perhaps other children will understand the importance of milk and dairy products in the development of the human body.

Research hypothesis.

I assumed that dairy products are obtained from milk using some kind of technology. I decided to experiment with milk to get dairy products.

Purpose of the study:Gain deeper knowledge about milk and dairy products. In accordance with the goal, the following project objectives:

1. Enrich knowledge about milk and dairy products.

2. Familiarize yourself with the methods of preparing dairy products.

3. Experiment with milk.

To form research skills in children (search for information in various sources).

To develop a cognitive interest in research activities, the desire to learn new things.

To develop the ability to work in a team, the desire to share information, to participate in joint experimental activities.

To form in children a conscious attitude towards healthy eating.

Hypothesis.

If children learn more about the value of milk and dairy products through their own research activities, then they will understand that milk is a valuable food for the child's body and they will have a desire to eat it.

The project is based on the research method of teaching (observation, search work, experimentation). This is a method in which children learn to conduct independent research, learn to collect available information about the object of study, record it, and expand their horizons. Children develop creativity and the ability to express their definitions, develop thinking and speech.

Chapter 1

The guys and I knew where milk comes from. But they thought that they only drink milk. But our educators Yulia Anatolyevna and Olga Eduardovna told us that milk can not only be drunk, it can be used to cook porridge, bake pancakes, cook various other dairy products. And what products are made from milk, they did not say, and offered to collect information about milk and dairy products.

Chapter 2 Gathering information about milk

First we decided to find out: What is milk? Is it good for a person? What are dairy products?

The children asked their parents, found out in the store what dairy products are. Here they are: kefir, butter, cheese, cottage cheese, varenets, curdled milk, bifidok, cream, yogurt, sour cream.

Our educators said that milk is the most useful food product for a person, because it contains a whole complex of vitamins (a complex is a lot of vitamins that together have a good effect on the human body). But we could not understand: “How do vitamins get into milk?” and put forward the hypothesis “Vitamins are added to milk by people. Or they get into milk through cow food.” Then they thought, and decided that people can eat vitamins anyway, without milk. It means through the grass and hay that the cow eats.

Chapter 3

We, under the guidance of educators, decided to experiment with milk and conducted the following experiments.

Experience number 1. Pour into 2 cans of fresh whole milk. One jar was put in the cold, the other - in the heat. And decided to observe how milk changes in the cold and in the heat? Looked after 2 days. In the cold, the milk did not change, only became cold. In the warmth, the milk turned sour, it became thick, it does not flow well, a little with flakes. We tasted it: the taste changed, became sour, but tasty. The teachers said that now it is not called milk, but yogurt.

We concluded: In the cold, milk does not change, it is stored. When warm, milk sours and turns into a new food product - yogurt (see appendix).

Experience number 2. We had a question: “What will happen to yogurt if it is heated even more?” Yulia Anatolyevna warmed up yogurt on a spirit stove, brought it to a boil and removed it. Thick flakes appeared in the curdled milk, and a yellow liquid separated. The teachers offered to strain it through gauze. The water was glassy and a thick mass remained. Got curd.

We concluded: To get cottage cheese, you need to heat yogurt to a boil and strain (see Appendix).

Cheese is made from cottage cheese. We learned about this from the encyclopedia. Cottage cheese is boiled in milk, then filtered, butter, soda are added and boiled again. Then they are laid out in molds and left to cool.

Experience No. 3 . We thought that the cow also gives the cream. But our educators said that cream is separated from milk by a special smart machine called a separator. If the cream stands for 2 days, it will become very thick, it is even difficult to put a spoon in. They offered to knock them down with a whisk or a mixer. We divided the cream into two parts. We knocked down one part with a whisk, the second part was knocked down with a mixer by Olga Eduardovna. All the cups contained oil.

We concluded: Cream can be separated from skimmed milk with a separator. If heavy cream is churned, then butter is obtained (see appendix). We added milk to heavy cream, stirred it and left it warm - we got sour cream (see appendix).

An experiment is an invention.We ourselves invented a new dairy product. Various fresh fruits and berries were added to fresh milk and beaten with a mixer. It made a great milkshake. Sugar was added for taste. We named this cocktail Strawberry Fantasy.

We really liked the experiment that Yulia Anatolyevna and Olga Eduardovna showed and explained to us. After that, we ourselves conducted this spectacular experiment:

1. Pour milk into a bowl.

2. Add a few drops of each dye to it. Try to do this carefully so as not to move the plate itself.

3. And now we will make the milk move with the help of a regular detergent. Take a cotton swab, dip it in the product and touch it to the very center of the plate of milk. See what happens! The milk will move and the colors will mix. A real explosion of color in a bowl! (see Attachment).

Experience Explanation:

When detergent is added to milk, the fat particles push the dye particles, the dye mixes with the milk, and beautiful curls are obtained.

Conclusion

In the process of experimenting with milk, we came to the conclusion:

1. Milk is the healthiest food for humans.

2. You can experiment with milk and get new dairy products: yogurt, sour cream, cottage cheese, cheese, butter, curdled milk and others.

3. We really enjoyed experimenting with milk, and we want to continue experimenting with vegetables and fruits.

List of used literature.

1. Children's encyclopedia.

2. Gorbatova K. K. Chemistry and physics of milk, ed. Giord, 2004

3. Shalygina A. M., Kalinina L. V. General technology of milk and dairy products.- M.: Kolos, 2007.

4. Material from Wikipedia - the free encyclopedia.

19 Aug 2012, Posted by admin

Prize-winner (2nd place) of the Regional competition of research works and creative projects of preschoolers and primary schoolchildren "I am a researcher" in 2010

Research

"Home experimentation with milk"

Researcher: Pupil of MDOU No. 3 "Buratino" Energetik, Novoorsky District, Orenburg Region Sitmukhambetova Asel(6 years)

Chapter 1 Why did I get interested in milk?

My grandmother has a cow Doll. I know where milk comes from. But I thought they only drink milk. Nadezhda Nikolaevna told me that I was mistaken. It turns out that milk can be used to cook porridge, bake pancakes, cook various other dairy products. And what products are made from milk, she did not say. Nadezhda Nikolaevna offered to start an investigation herself and find out about them.

Chapter 2 Gathering information about milk

First I decided to find out: What is milk? Is it good for a person? What are dairy products?

I conducted a survey among the guys, found out in the store what dairy products are. They called me : kefir, butter, cheese, cottage cheese, varenets, curdled milk, bifidok, cream, yogurt, sour cream.

Nurse Nadezhda Alekseevna said that milk is the most useful food product for humans, because it contains a whole vitamin complex(complex - a lot of vitamins that together well affect the human body). I asked myself the question: How do vitamins get into milk? and put forward hypothesis “Vitamins are added to milk by people. Or they get into milk through cow food.”. Then I thought, and decided that people can eat vitamins anyway, without milk. Means through the grass and hay that the cow eats .

Chapter 3

I decided to experiment with milk. My teacher told me that other dairy products are obtained by adding bacteria to the milk, mixing it with other foods, or changing the storage temperature of the milk.

Experience #1. I poured into 2 cans of fresh whole milk. I put one jar in the cold, put the other in heat. And I decided to observe how milk changes in the cold and in the heat? I looked after 2 days. In the cold, the milk did not change, only became cold. In the warmth, the milk turned sour, it became thick, it does not flow well, a little with flakes. I tasted it: the taste changed, became sour, but tasty. Nadezhda Nikolaevna said that now it is called not milk, but curdled milk. I added jam to yogurt, it turned out yogurt.

I concluded: In the cold, milk does not change, it is stored. When warm, milk sours and turns into a new food product - yogurt. If you add jam to curdled milk, you get yogurt.

Experience number 2. I have a question: What will happen to curdled milk if it is heated even more? I put the curdled milk on the fire, brought it to a boil and turned off the gas. Thick flakes appeared in the curdled milk and a yellow liquid separated. Nadezhda Nikolaevna offered to strain it through a colander. The water was glassy and a thick mass remained. I tried and it's cottage cheese.

I concluded: To get cottage cheese, you need to heat yogurt to a boil and strain.

Cheese is made from cottage cheese. This is what I saw in a dairy. Cottage cheese is boiled in milk, then filtered, butter, soda are added and boiled again. Then they are laid out in molds and left to cool.

Experience No. 3. Mom and I drank tea with cream. I thought that the cow also gives the cream. But mom said that cream is separated from milk by a special smart machine that called a separator . I tried and I succeeded. Separator divided separately cream(full milk) from return(processed, non-fat milk). I brought the cream to the kindergarten to show everyone. The cream stood for 2 days, and became very thick, it is even difficult to put a spoon into it. I didn't know what to do with them. Nadezhda Nikolaevna suggested knocking them down with a whisk, a mixer, a mortar. I divided them into 3 parts. One part was knocked down with a whisk, the second part was knocked down with a mixer, the third part was knocked down with a mortar. In all cups it turned out oil.

I concluded: Cream can be separated from low-fat milk separator. If you churn heavy cream, you get butter. If there is a lot of thick cream, then the housewives churn butter in a home churn.

Experience No. 4.I decided to find out what will turn out with milk, if it add bacteria . I learned about bacteria in the store by reading the recipes on the packages of dairy products.

It turns out that if you add special lactic bacteria to boiled chilled milk, then the milk will turn into bifidok, varenets or kefir. . I bought them at the store, made them as directed in the recipe, and after 2 days I had new dairy products: kefir, varenets, bifidok.

An experiment is an invention. I invented a new dairy product myself. I added various fresh fruits and berries to fresh village milk and beat with a mixer. It turns out great milkshake. Added sugar for taste. I want to treat you to a milkshake, which I will prepare right in front of you. I called this cocktail “Strawberry Fantasy”.

Chapter 4. Conclusions

In the process of experimenting with milk, I came to the conclusion:

1. Milk is the healthiest food for humans.

2. You can experiment with milk and get new dairy products: yogurt, sour cream, cottage cheese, cheese, butter, curdled milk and others.

3. I liked experimenting. Later I want to experiment with vegetables and fruits.

Chapter 5 Helpful Dairy Tips

I interviewed grandmothers - neighbors about how best to store dairy products. They have a lot of experience. Got " Helpful Dairy Tips:

1. To keep dairy products from spoiling longer, they must be kept in the dark.

2. If, before boiling, add half a spoonful of sugar per 1 liter of milk to milk, boil, cool, put uncovered, then such milk will not turn sour even without a refrigerator for 2-3 days.

3. It is better to boil milk in a saucepan with a thick bottom so that the milk does not burn.

4. Dairy products quickly absorb foreign odors, so they should not be kept near odorous products.

5. If there is no refrigerator, the cheese should be stored wrapped in a cloth soaked in salt water.

6. Mustard is better preserved if it is diluted with milk instead of water.

7. When preparing mashed potatoes, it is better to use hot milk: mashed potatoes turn gray from cold milk.

8. If the milk is burnt, do not stir it. Pour immediately into another bowl so that the smell of burning does not remain.

9. It is better to cover the flooded place of runaway milk with a wet newspaper, then the smell of burnt milk will not spread throughout the kitchen.

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