Lesson “Determining the density of an irregularly shaped body. II

Definitiondensityhard-breathtelwrongforms

The characteristic of solids noted above suggests that their volume cannot be calculated by the product of data obtained by measuring parameters such as length, width, etc. Instead, another method of determining the value of V can be used, such as displacement. Examples of irregularly shaped solids are rock, which has a higher density than water, and cork, which is less dense than water.

Definitiondensitystone.
The measuring cylinder, the dimensions of which are sufficient to place a stone in it, partially fill it with water (Fig. 2.5, a). Note the volume V of the water in the measuring cylinder and write it down in cm, not ml. It would be reasonable to choose such an amount of water that its initial volume V 1 would be expressed as an integer, for example 20 or 30 cm 3, so that later it would be easier to subtract. Determine the mass of the stone m using a balance. Then tie a thread to the stone and carefully lower it into the water so that it is completely immersed in it. (Why do you think a thread is used and not a wire?) The water level will rise and show the volume V 2 that you read from the scale of the measuring cylinder. This volume is the total volume of water and stone. Therefore, the volume V of the stone is determined from the formula V = V 2 - V1.

Note. The volume of water used did not change, but the stone occupied part of the volume that was filled with water, and therefore the water level rose.

The density of a stone can be calculated using the formula:

This method only works for solids that do not dissolve in water. If a soluble solid is placed in water, the water level may not rise at all. The molecules of this solid body will be distributed evenly over the volume and will be introduced into the "space" between the water molecules.

Cork. In order to determine the volume of a solid body floating in water, such as a cork, a sinker should be attached to it, which ensures that the cork is completely immersed. Fill the drain vessel with water and let it flow out so that the water level in the vessel is exactly at the level of the drain (Fig. 2.5, b). Place the measuring cylinder under the drain. Then attach the thread to the sinker and carefully lower it into the water until it is completely submerged. The volume V 1 of the sinker will cause an equal volume of water to flow into the measuring vessel. Volume V 1 , water in the measuring cylinder is equal to the volume of the sinker. Then determine the mass m of the cork using a balance. Tie a cork and sinker together and lower this pair of solids into the water in a vessel. Water will again overflow through the drain into the measuring vessel, this time in an amount equal to the volume of the plug. The volume V 2 of the water in the measuring cylinder is the volume of the cork and sinker. The volume V of the plug is calculated by the formula V = V 2 - V 1. Thus, the density of the tube is.

Municipal budgetary educational institution lyceum No. 4 of the city of Dankov, Lipetsk region.

Section of natural sciences.

Research project in physics on the topic:

Determination of the density of solids in various ways.

Completed by: 7th grade students

Kozhemyakina Julia

Kostyukhin Valery.

Supervisor:

Anokhina Nina Alekseevna,

Physics teacher.

Dankov 2012.

2.Introduction. page 3

1) Aggregate states of matter. page 3

2) The structure of solid bodies. page 3

3) Literature analysis. page 3

4) Purpose, object, subject, hypothesis, tasks, methods of project research. page 3

3. The main part. page 4

1) The density of matter. page 4

2) The formula for calculating the density of a body. page 4

3) Determination of the density of laundry soap. page 4

4) Determination of the density of an orange. page 5

5) Determination of stone density. page 5

6) Determination of cork density. page 6

7) Determination of the density of an apple. page 6

8) Determination of the volume of the human body by a geometric formula. page 6

9) The secret of the golden crown. page 7

10) Determination of the volume of the human body by the method of Archimedes. page 8

11) Calculation of the average density of the human body. page 8

12) Analysis of the obtained results. page 8 4. Conclusion. page 9 5. List of used literature. page 10

6. Annex 1 (Presentation).

Introduction.

On Earth, we are surrounded by a great variety of different bodies. All of them are made up of matter. Depending on the conditions, the same substance can be in different states: solid, liquid or gaseous. We know that the molecules of the same substance in the solid, liquid and gaseous state are no different from each other. This or that state of aggregation of a substance is determined by the location, nature of the movement and interaction of molecules. Most of the objects around us are made up of solids. If we consider the same substance in different aggregate states, then its density will be different!

The density of a substance depends on the mass of the atoms of which it is composed, and on the packing density of atoms and molecules in the substance. The greater the mass of atoms, the greater the density. In solids, the atoms are tightly bound to each other and very densely packed. Therefore, a substance in a solid state has the highest density. Solid bodies have their own shape and volume. They can be divided into two groups: bodies that have regular and irregular geometric shapes.

We wanted to know how to determine the density of solids.

Having become acquainted with the scientific articles of Tikhomirova S.A., Perelman Ya.I., Khutorsky A.V., Maslov I.S., and others, we found some answers to our questions.

Based on the above, we have formulated objective of the project: to investigate the dependence of body mass on the type of substance and its volume; find out the physical meaning of density.

object of our study are solids.

Thing: setting up experiments in physics using various solids.

Hypothesis: the human body is 75% water, because their densities differ little from each other.

In accordance with the purpose, object, subject, we have determined project tasks: 1. Analyze the scientific literature on the topic of the project.

2. Determine the density of solids that have regular and irregular geometric shapes.

3. Determine the density of the human body.

4. Develop and reproduce physical experiments with solid bodies.

The following were used in the project research methods:

1. Study of literature.

2.Experiment.

3. Analysis.

4. Comparison.

Main part.

Measure everything that can be measured

and what does not lend itself - to make measurable.

G. Galileo.

At the lessons of physics, we got acquainted with the physical quantity "density of matter". Density, by definition, is a physical quantity numerically equal to the ratio of a body's mass to its volume. Accordingly, to calculate it, it is required to measure the volume and mass of the body. The density of a substance depends on the mass of the atoms of which it is composed, and on the packing density of atoms and molecules in the substance. The greater the mass of atoms, the greater the density. The density of substances usually decreases with increasing temperature (due to thermal expansion of bodies) and increases with increasing pressure. During the transition from one state of aggregation to another, the density of bodies changes. The unit of density in the International System of Units is kg/m3. In practice, the following units are also used: g / cm3, g / l ...

The density of a substance is equal to the ratio of the mass of a body to the volume of this body. (App. 1. Slide 3)

ρ=m/v

ρ - density, kg / m 3

m - body weight, kg

V - body volume, m 3

as you can see, to determine the density of any body, it is necessary to know the mass of the substance (it is determined using weights), and the volume of the body.

If the body is of the correct geometric shape, then its volume can be determined by mathematical formulas.

Determination of the density of a bar of laundry soap. (App.1 Slide 4.5)

Necessary equipment: ruler, scales.

A bar of soap has the shape of a rectangular parallelepiped. The volume of a rectangular prism is equal to the product of the area of the base and the height. The ruler measured the length, width and height of a bar of soap: a=8.5cm, b=5.7cm, c=3cm. Based on these data, the volume of the body was calculated. V = abs. V = 8.5*5.7*3=145.35cm3=0.000145m3. The mass of soap was found using scales.m = 174gr = 0.174 kg. According to these data, it was obtained that the density of the soap is 1200 kg/m 3 .

Determination of the density of an orange. (Appendix 1 Slide 6.7)

Necessary equipment: ruler, scales.

We took an orange, which has the shape of a ball. Its volume was found by the mathematical formula:

where R is the radius of the orange. To determine the radius of an orange, we cut it in half and measured the distance from the center to the peel with a ruler.

R \u003d 3.2 cm \u003d 0.032 m. V = 0.000137m3.

The mass of an orange was determined on a scale, m = 150 g = 0.15 kg. According to our calculations, the density of an orange is 1095 kg / m 3

If an orange is lowered into water, then it will sink. its density is greater than that of water.

Determination of the density of irregularly shaped solids.

The volume of irregularly shaped solids cannot be calculated by multiplying data obtained by measuring parameters such as length, width, etc. Instead, another technique for determining the volume value, such as displacement, can be used. Examples of irregularly shaped solids are an apple, a stone, a cork, a human body ...

3. Determination of stone density. (App. 1 Slide 8)

Necessary equipment: ruler, scales, measuring cylinder (beaker) with water.

A measuring cylinder, large enough to hold a stone, was partially filled with water. The volume V1 of water in the measuring cylinder was noted. V1=180cm3. The mass of the stone m was determined using a balance. Then they tied a thread to the stone and carefully lowered it into the water so that it was completely immersed in it. The water level rose and the volume became V2=194cm3. This volume is the total volume of water and stone. Therefore, the volume V of the stone is determined from the formula V = V2 - V1. V= 14cm3=0.000014m3.

The volume of water used did not change, but the stone occupied part of the volume that was filled with water, and therefore the water level rose.

The mass of the stone was determined on the scales m = 36.5 g = 0.0363 kg.

Density was calculated using the formula:

ρ=m /v ρ=2593 kg/m 3

4.Determination of cork density. (App.1 Slide 9,10) In order to determine the volume V of a solid body floating in water, such as a cork, we attached a sinker to it, which ensures that the cork is completely immersed. Water was poured into the beaker. Then they attached the thread to the sinker and carefully lowered it into the water until it was completely immersed. The volume of water in the measuring cylinder has increased to V2. Then the cork was untied and the volume V1 of the sinker was determined by the same method. The volume V of the cork was found by the formula V = V2-V1, V = 20 cm3 = 0.00002 m3. The mass m of the cork was determined using scales, m=4.9g=0.0049kg. Thus, the cork density is 245 kg / m 3

5. Determining the Density of an Apple.(App.1 Slide 11,12,13)

The mass of an apple was determined on the scales, it is equal to 120 g or 0.12 kg.

The volume of the body cannot be determined using a beaker, because the apple is larger than the size of the beaker. In order to determine the volume of a solid body, we used a pouring cup. An apple floats in the water, so we picked up a pouring glass into which the apple entered with the help of our little efforts.

We filled the pouring cup with water and let it flow out so that the level of water in the vessel was exactly at the level of the drain. Place an apple in a glass. The volume V1 of the apple causes an equal volume of water to flow into the vessel. The volume of displaced water was determined using a beaker. The volume V1 of water in the measuring cylinder is equal to the volume of an apple. V1= 150cm3 or 0.00015m3 The mass m of an apple was found using a balance. m = 120g or 0.12 kg. Thus, the density of an apple is 800 kg / m 3

6. Determination of the density of the human body. The mass of a person can be determined using floor scales.

A beaker is not suitable for determining the volume of a human body, and we considered several options for solving this problem:

The first option for determining the volume of the human body (App. 1 Slide 14):

You can model the human body from geometric shapes: the head is a ball, arms, legs are truncated cones, the body is a rectangular parallelepiped

and the total volume will be equal to the volumes

V = V Goal + V tul +2 V hands +2 V legs

this path is very complex and requires knowledge of the volume formulas of various geometric shapes and complex mathematical calculations.

The second option for determining the volume of the body (App. 1 Slide 15):

In physics lessons, we studied the force of Archimedes. When explaining the new material, the teacher told the legend about the secret of the golden crown. We decided to measure the volumes of our bodies in this way.

Mystery of the golden crown. About 2200 years ago, a scientist, mathematician, and philosopher named Archimedes lived in Greece. He was at the court of King Hieron II. The king had a crown, which he, when required for impressiveness, placed on his head, appearing before his subjects.

However, this is how kings are arranged, he was haunted by the thought that the crown was not made of pure gold, which means that he, the almighty ruler, will be deceived by the goldsmith and wears a fake on his head. It can be assumed that such a restless king as Hieron thought to weigh the gold before giving it to the master. Then it was only necessary to check the mass of the finished crown to find out if the jeweler had stolen some of the gold. Probably Hieron did just that and found that its mass exactly coincided with the original mass of gold.

But Hieron was a quick-witted, albeit very suspicious person. One can imagine how he reasoned, following the possible thoughts of the goldsmith: “I can deceive the king by appropriating a small piece of gold, replacing it with an equal mass of silver, a less expensive metal, and alloying it with gold. I will do everything so that the mass of the crown would be equal to the mass of gold entrusted to me. And if you steal a little gold, then the appearance of the crown will not differ from gold.

This possibility worried the king, so he called his court scientist Archimedes and instructed him to conduct an investigation and find out if the theft was committed in the described way.

One day, Archimedes was meditating on a royal task while sitting in a bath. And suddenly, as the legend says, the solution to the problem suddenly occurred to him. He is said to have been so excited that he jumped out of the tub and ran through the streets of his hometown of Syracuse, shouting “Eureka! Eureka!" which means "Found it! Found!".

And the scientist found not only a way to fulfill the task of the king, but also the ratio between the force pushing an object immersed in a liquid and the volume of the liquid displaced by it.

Archimedes discovered and formulated in his law that the buoyant force is equal in magnitude to the force of gravity acting on the water displaced by the body.

Archimedes' principle states that a body immersed in a fluid is subjected to a buoyant force directed upwards and equal in absolute value to the weight of the fluid that the body displaces.

Using this method, we filled 2/3 of the tub with water and made a mark. When a person is completely immersed in a bath, the water level rises. Made a second mark. Using a liter jar, and by the difference in water levels before and after immersion in the bath, we determined the volume of the body.

To determine the density of the human body, you need to know the mass, which was determined using floor scales.

Experiment results (App.1 Slide 16):

Subject's name

Weight, kg

Volume

Density. kg / m 3

45 0.045

53 0.053

The average value of the density of the human body is 1044kg/m 3 .

Conclusion: We experimentally obtained the average value of the density of the human body, it turned out to be approximately equal to the density of water. Therefore, a person can swim. It is easier to swim in sea water than in fresh water, since the density of pure water is 1000 kg / m 3, and the density of sea water is 1030 kg / m 3.

No wonder they say that a person consists of 75% water!

Conclusion.

What does it mean to measure a physical quantity correctly? This question is not easy to answer. This paper discusses various methods for determining the density of an irregularly shaped body and analyzes the results obtained. The theoretical assessment of the proposed result is supported by practice. The considered methods can be used in practice in determining the density of a body that has an irregular shape.

While working on the project, we learned a lot of new and interesting things about the density of various substances:

To measure the density of liquid and bulk substances, there are devices called hydrometers, with the help of which they measure

electrolyte density in acid and alkaline batteries.

density of whole and skimmed milk, oil and oil products

density of solutions of salts and acids, solutions of cement and concrete, etc.

Usually solids sink in their melts

for example, a piece of butter will sink in ghee, an iron nail will sink in molten iron.

But there are no rules without exception: the ice formed in winter does not sink, but floats on the surface of the water, since the density of ice is less than the density of water. Otherwise, all reservoirs would be filled with ice in winter and living organisms could not exist in them.

In Italy, near Naples, there is the famous "dog cave". In its lower part, carbon dioxide is continuously released, the density of which is 1.5 times greater than the density of air. Gas creeps down and slowly leaves the cave. A person can freely enter the cave, for a dog such a walk ends sadly.

4. The earth's crust consists of layers that differ in density. The average values of the density of the earth's crust and the Earth as a whole are 2700 kg / m 3 and 5520 kg / m 3, respectively.

Bibliography:

1. Peryshkin A.V. "Physics grade 7" Publishing house "Drofa" 2010

2. Khutorskoy A.V. , Khutorskaya L.N., Maslov I.S. "How to Become a Scientist". Moscow Globus. 3. Landsberg G.S. Elementary textbook of physics.T.1. – M.; AOZT Shrike, 1995.

4.Physics-7. Edited by A.A. Pinsky, V.G. Razumovsky, 1993.

5. Perelman Ya.I. Entertaining physics. Moscow. 2005.

6. Kabardin O.F. Reference materials on physics. M. 2007.

7. Internet resources.

The product of our work is a presentation that can be used by a physics teacher when studying the topic "matter density". (Appendix 1.)

Development of an integrated lesson in physics in the 7th grade on the topic: "Determination of the density of an irregularly shaped body."

Teacher: Shamukaev Salai Milayevich.

Goals:

Educational.

To acquaint students with determining the density of an irregular body, with determining the degree of starch content in potatoes, with the history of the appearance of potatoes in Russia, with the growth of potatoes in Bashkiria.

Developing.

Formation of the ability to express inferences; develop the ability to reproduce the acquired knowledge according to the plan; work with spreadsheets; development of logical thinking, memory, attention.

Educational.

Contribute to the education of humanity, discipline, diligence; cognitive interest in new knowledge.

Equipment: beaker, flask with water, thread, laboratory scales with a set of weights, iodine solution, pipette.

During the classes.

organizational part.

Actualization of knowledge: frontal survey.

How to determine the division value of a beaker?

How to determine the volume of a body of regular geometric shape?

How to determine body weight?

How to determine the density of a body?

How can you determine the volume of an irregularly shaped body?

Messages from history.

1 student: Growing potatoes is like picking three ears where one grew. The path that the potato has traveled has been difficult and long.

“There were many miracles with her,

Until she got to us.

The path was long and far

From West to East."

2 student: It was a very long time ago, over 400 years ago. Far away on the opposite side of the world, this ancient mountainous country stretches along the Pacific Ocean, where the ancestors of the American Indians found wild potato tubers and began to plant them near their homes.

3 student : The potato began its journey to Spain, then to Italy, England. Potatoes came to India, Iran and other countries from Europe in the 18th century, and to China even earlier - at the beginning of the 17th century. At the end of the 17th century, this plant was brought to Russia. Peter I , being at that time in Holland, sent B. Sheremetyev a bag of potatoes. In 1736, the potato was already listed in the plant catalog of the St. Petersburg Apothecary Garden.

4 student : At first, the peasants considered it a sin to eat potatoes. They went to hard labor, but refused to grow potatoes. In 1842, a "potato riot" broke out in the Perm province. It arose after Tsar Nicholas I ordered the peasants of a number of provinces to plant potatoes without fail. The real invasion of the potato took place only after the October Revolution.

5 student : The path of the potato through the countries of Europe was difficult. But in the end, this culture won universal recognition. It was recognized that "earth apples" satisfy hunger very well. The catchphrase "potatoes are the second bread" has become true.

IV . Laboratory work on the topic "Determining the density of potatoes and the degree of starch content in it."

Teacher: Guys, you listened to very interesting messages. And now we will do the laboratory work. Let's split into teams. Each team chooses a captain who, after the end of your work, must make a report. I'm handing out work notes.

Determine the volume of potatoes using a beaker.

Determine the mass of potatoes using a scale.

Determine the density of potatoes in g / cm 3 .

Determine the degree of starch content in potatoes and its dependence on density (to do this, you need to drop a drop of iodine on potatoes and judge the presence of starch by the intensity of the iodine color change).

Fill in the table:

Variety potatoes.	Volume potato, cm 3	Weight potato,	Density potato, g/cm 3	Degree availability starch,

Teacher: You have done the work. We heard the team captains. We made conclusions. Now let's watch the show.

V. Scene.

Participants: Host, Potato, Ecologist.

Leading : Hello! The program "Our Garden" is on the air. And with you I am the host of the program. Today Potato and his defender Ecologist came to visit us. Let's ask them a few questions. Potato, how did you appear in Bashkortostan?

Potato : I have been growing up in Bashkortostan for a long time. Russian settlers brought me here in the middle of the 19th century. Here they call me the second bread and everyone loves me - Bashkirs, Russians, Tatars, Chuvashs and other peoples inhabiting this multinational region.

Leading : But you, dear Potato, are ecologically unfavorable crops. And you deplete the soil, and suffer from many diseases that are treated with pesticides. And in the last decade, our “old friend” came to you from America - the Colorado potato beetle, which multiplies so much that if chemical preparations are not used, it leaves us without a crop.

Dear Ecologist, can you help Potato become environmentally friendly?

Ecologist : We are already helping. Breeders have bred potato varieties that do not suffer from either fungal or viral diseases. As for the Colorado potato beetle, we are looking for an enemy of this pest that can control its numbers.

Leading : But so far, as far as I know, they haven't found it. So what about Potatoes?

Ecologist : If the Colorado potato beetle eats a small part of the green mass of potatoes (no more than 20-30%), then the tuber yield does not decrease). The fact is that on the "openwork crown" of the plant, all the leaves are well lit and therefore actively photosynthesize. In addition, varieties of potatoes with tasteless leaves have already been bred. The Colorado potato beetle eats them very badly.

Leading : What about soil fertility? After all, under potatoes, the soil is quickly depleted.

Potato : Ecologist is right. If, after me, clover and timothy grass are sown in this field for two or three years, then they will completely restore both the structure of the soil and its fertility.

Leading : I am happy for our friend, for the Potato, who stepped over with other crops into the new millennium.

VI . Report of the teacher of technology and labor training on the topic: "Potatoes and its use: dishes, treatment, cosmetics."

Teacher: And now let's listen to the teacher of technology and labor training Dudareva Marina Alexandrovna. She will tell us a lot of interesting things about the use of potatoes in cooking, medicine, and cosmetics.

Hearing a report Appendix 1).

VII. Summary of the lesson.

Teacher: So our lesson is over. I hope that you have learned a lot of interesting and useful things for yourself. This knowledge will help you in your future life.

Write down your homework: repeat item 21, exercise No. 7 (4,5) in writing.

Thanks everyone for the lesson.

Appendix 1.

Topic: Potato and its use: dishes, treatment, cosmetics.

Health is the peak that everyone must reach for himself.

Potato is one of the most unique and diverse plants on Earth. Botanists number from several tens to hundreds of its species and varieties. Potato as a representative of the nightshade family is related to tomato, vegetable pepper, eggplant. It is not in vain that it is called the “second bread” in Russia, since its share in the diet here is significant.

The homeland of potatoes is considered to be South and Central America. Here, in the distant past, the local Indian tribes of Chibcha and Araucan learned to cultivate wild potatoes and eat them.

Potatoes were brought from South America to Europe (Spain) in the second half of the 16th century, and from Spain they came to Italy, Belgium, England, France, Germany, Holland and other countries.

There is no exact data on the time of appearance of potatoes in Russia. There is only a version that this happened at the end of the 17th century. Peter I, during his trip to Holland, sent a bag of potatoes to Count Sheremetyev with an order to take care of its distribution. But the order to breed some unknown vegetable did not meet with sympathy, and the potato spread only among a limited circle of people, mainly the wealthy class and foreigners. Outside of St. Petersburg, he remained unknown for a long time, and in Western Europe at that time (the beginning of the eighteenth century) potatoes were already being cultivated. But there is evidence that in 1740 potatoes were grown near St. Petersburg, and they were served in small quantities at court banquets ...

For a long time, potatoes in European countries were planted mainly in botanical gardens and pharmaceutical gardens. It took more than 100 years before he got from the botanical gardens to the gardens of the peasants. Under Catherine II, the government, making sure that our climatic conditions are favorable for the cultivation of potatoes, took measures for its widespread distribution. Over time, potatoes ceased to be something unfamiliar, became widespread and used in Russia.

The nutritional value of potatoes was not immediately recognized. Many were extremely distrustful of the new product. Some cursed "damn apples", and some doctors claimed that potato tubers are poisonous and cause disease.

The transition of potatoes from garden crops to field crops was carried out gradually, as demand for products increased.

Now let's look at the chemical composition of potatoes. It includes 75% water, with over 19% sugar, 0.2% fat, vitamins A, B, C, various proteins. Vitamins and proteins are also found in greater quantities in potato peels. Potato tubers contain 20-25% dry matter, 15-20% starch, about 2% protein and 0.1-0.3% fat. It is established that 250-300g. A boiled potato is enough to meet 50% of a person's daily vitamin C requirement.

Potatoes are a versatile vegetable that can be boiled in water or steamed, fried in a pan, oven or deep fried, baked, boiled and then fried, and used in pies, pancakes, casseroles, gravies and soups.

Cooking potatoes peeled or with skins depends on the type of potato, cooking method, and your personal preferences. However, it should be borne in mind that the skin of a potato contains many useful substances, it is better to leave it if possible. It is important to completely remove the green part of the tuber before heat treatment.

Young small potatoes are good steamed or boiled as a side dish or in salads. Ripe white oblong potatoes are used for baking, mashing or french fries. Round red potatoes are great for boiling and mashing. Round white potatoes are good boiled orroasted in the oven. Yellow-fleshed potatoes taste great when steamed or roasted in the oven. The taste of potatoes is enhanced by many spices (dill, basil, onion, garlic, cilantro, fennel, oregano, parsley, rosemary, tarragon, sage, thyme), as well as fats (butter and vegetable oil, sour cream, cream and milk). Potatoes are ideally combined to taste with meat, poultry, game, fish, and vegetable dishes. Roasted potatoes are an integral part of the traditional Sunday roast, as well as the Christmas and Easter meals in many countries. Unfortunately, "harmful" foods made from the same healthy potatoes are very popular - potato chips and french fries.

With the help of potatoes, you can get rid of many diseases. Of particular note are the healing properties of fresh potato juice, which has anti-inflammatory, antispasmodic, wound healing, diuretic and tonic properties. It is used in the treatment of gastritis with high acidity, peptic ulcer. Potato juice inhibits the secretion of the gastric glands, has an analgesic effect and promotes scarring of ulcers. To prepare juice, young potatoes are taken, washed, grated or passed through a meat grinder, then juice is squeezed out of the resulting pulp through cheesecloth. It is necessary to drink 100-150 ml of freshly squeezed potato juice every morning on an empty stomach 20 minutes before meals, and in most cases it will be possible to forget about pain in the stomach very soon. Potato fiber does not irritate the mucous membrane of the stomach and intestines, boiled potatoes can be eaten even during exacerbation of gastritis and ulcers. An infusion of potato flowers lowers blood pressure and activates respiration. They are treated with benign tumors - mastopathy, myoma. Potato flowers are also used for cancerous tumors.
Potato flowers infused with vodka are an excellent remedy for sciatica. Fresh or dried potato flowers are good for treating sore throats. Take 2-3 potato flowers and brew with one glass of boiling water. Let it brew for 10-15 minutes, and then gargle with warm infusion as often as possible. In two or three days, with the help of such rinses, a sore throat can be cured.
Nicotinic acid (vitamin PP), contained in potatoes, will help reduce calluses. To do this, it is necessary to apply potato gruel to the sore spot.
Potato starch reduces cholesterol in the liver and blood serum, that is, it has anti-sclerotic properties.
Raw potato candles help with hemorrhoids. Traditional medicine suggests applying cut potato slices to the forehead or drinking potato juice during headaches.
Potato face masks have amazing properties. They nourish, soften even the roughest skin, put in order too active sebaceous glands and even perform a real lifting - they tighten the skin and smooth out wrinkles.

Interesting Facts.

There is a potato museum in Belgium. Among its exhibits are thousands of items telling about the history of the potato, from postage stamps with its image to famous paintings on the same theme (Van Gogh's The Potato Eaters).

On some tropical islands, potatoes were used as the equivalent of money.

Poems and ballads were dedicated to potatoes.

The great Johann Sebastian Bach once glorified the potato in his music.

In modern Iceland, vodka made from potatoes is popular.

There are two rare varieties in which the color of the skin and flesh remains blue even after boiling: Linzer Blaue and Französische Trüffel-Kartoffel.

One of the most common blue-skinned varieties grown in Russian gardens is "blue-eye". However, few people know what is scientifically called "Hannibal", in honor of the great-grandfather of Alexander Sergeevich Pushkin, Abram Ganibal, who was the first to conduct experiments on the selection and storage of potatoes in Russia.

In the city of Minsk in the 2000s, a monument to potatoes was opened. In Mariinsk (Kemerovo region) will soon open.

The United Nations declared 2008 the International Year of the Potato.

Instruction Card #2

Lab #1

Subject. DETERMINATION OF THE DENSITY OF A SOLID AND LIQUID.

Target: Determine the density of solids and liquids.

Equipment: scales with weights; measuring cylinder; ruler; investigated solids (a wooden block, a piece of sugar, a metal cylinder with a thread); a glass with the investigated liquid (lemonade or mineral water), bulk material (sand).

Theoretical preparation: The density of a substance is a value equal to the ratio of body mass m to its volume V; in other words, the density of a substance is a value that shows what the mass of a substance in a unit volume is equal to.

Density is measured in g/cm 3 , kg/m 3 .

To find the density of a substance, you need to know the mass and volume of the body that is made of this substance.

Experiment No. 1. Determination of the density of bodies of regular geometric shape.

Working process:

1. Take the body of the correct geometric shape. For example, a wooden block.

2. Use a balance to determine the mass of the block.

3. Determine the dimensions of the bar using a ruler. Calculate the volume of the bar using the formula:

a– length, cm

b– width, cm

h– height, cm

4. Calculate the density of the body.

5. By repeating steps 2-4, calculate the density of the sugar cube.

Experiment No. 2. Determination of the density of liquids and loose bodies.

Working process:

1. To determine the mass of a liquid, place an empty beaker on the scale. Balance the scales.

2. Pour liquid into a beaker and use a balance to determine its mass.

3. Determine the volume of the poured liquid from the divisions of the beaker.

4. Calculate the density of the liquid.

5. Repeating steps 1-4, determine the density of the bulk material.

Experiment No. 3. Determination of the density of bodies of irregular geometric shape.

Working process:

1. Take an irregularly shaped body. For example, a piece of plasticine or a paraffin candle.

2. Use a scale to determine the weight of the body.

3. To determine the volume of an irregularly shaped body, use the experience of Archimedes:

Pour water into the measuring beaker. Remember its volume.

Dip the body whose volume you want to determine into the water. Remember the value of the volume of liquid.

Calculate the difference between the two volumes (initial and final). It is this difference that will be the volume of the irregularly shaped body.

4. Calculate the density of the body.

5. Repeating steps 1-4, calculate the density of the metal cylinder.

6. According to the table of densities, determine the material from which the cylinder is made.

Work form:

1. Fill in the table:

Investigated body, liquid	Mass m, g	Volume V, cm 3	Density r
g/cm 3	kg / m 3
EXPERIMENT #1


EXPERIMENT #2


EXPERIMENT #3

2. Make a conclusion in which do not forget to indicate the factors that could affect the accuracy of the results.

Make sure the body is waterproof, as the method described involves immersing the body in water. If the body is hollow or water can penetrate it, then you will not be able to accurately determine its volume using this method. If the body absorbs water, make sure the water will not damage it. Do not immerse electrical or electronic items in water as this may result in electric shock and/or damage to the item itself.

If possible, seal the body in a waterproof plastic bag (after releasing the air). In this case, you will calculate a fairly accurate value for the volume of the body, since the volume of the plastic bag is likely to be small (compared to the volume of the body).

Find a container that holds the body whose volume you are calculating. If you are measuring the volume of a small object, use a measuring cup with a graduation (scale) of volume. Otherwise, find a container whose volume can be easily calculated, such as a cuboid, cube, or cylinder (a glass can also be thought of as a cylindrical container).

Take a dry towel to lay the body out of the water on.

Fill the container with water so that the body can be completely immersed in it, but at the same time leave enough space between the surface of the water and the top edge of the container. If the base of the body has an irregular shape, such as rounded bottom corners, fill the container so that the surface of the water reaches the regular part of the body, such as straight rectangular walls.

Note the water level. If the water container is transparent, mark the level on the outside of the container with a waterproof marker. Otherwise, mark the water level on the inside of the container using colored tape.

If you are using a measuring cup, then you do not need to mark anything. Just write down the water level according to the graduation (scale) on the glass.

Immerse your body completely in water. If it absorbs water, wait at least thirty seconds and then pull the body out of the water. The water level must go down because some of the water is in the body. Remove marks (marker or adhesive tape) from the previous water level and mark the new level. Then once again immerse the body in water and leave it there.

If the body is floating, attach a heavy object to it (as a sinker) and continue the calculation with it. After that, repeat the calculation exclusively with the sinker to find its volume. Then subtract the volume of the lead from the volume of the body with the weight attached and you will find the volume of the body.

When calculating the volume of the sinker, attach to it what you used to attach the sinker to the body in question (for example, tape or pins).

Mark the water level with the body submerged in it. If you are using a measuring cup, record the water level according to the scale on the cup. Now you can pull the body out of the water.

The change in the volume of water is equal to the volume of an irregularly shaped body. The method for measuring the volume of a body using a container of water is based on the fact that when a body is immersed in a liquid, the volume of the liquid with the body immersed in it increases by the volume of the body (that is, the body displaces a volume of water equal to the volume of this body). Depending on the shape of the water container used, there are different ways to calculate the volume of water displaced, which is equal to the volume of the body.

If you used a measuring cup, then you have recorded two values \u200b\u200bof the water level (its volume). In this case, from the value of the volume of water with the body immersed in it, subtract the value of the volume of water before the body is immersed. You will get the volume of the body.

If you used a cuboid container, measure the distance between the two marks (the water level before the body is submerged and the water level after the body is submerged), as well as the length and width of the water container. Find the volume of water displaced by multiplying the length and width of the container, as well as the distance between the two marks (that is, you calculate the volume of a small rectangular parallelepiped). You will get the volume of the body.

Do not measure the height of the water container. Measure only the distance between the two marks.
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