Elective course program in physics

Experiments in physics

"Know yourself".

Program compiler: Avakyan Lyudmila Gennadievna

Explanatory note.

The program lasts 8 hours.

Physics is an experimental science and practical work should occupy a significant part of the physics course.

Man is a part of nature, and his body is subject to the same laws of physics. Socrates’ “Know thyself” is understood by us, including how to know your body and the physical laws to which it obeys. Practical work on studying one’s body arouses genuine interest among students.

Course objectives:

Creating conditions for the formation and development of students:

intellectual and practical skills in the field of physical experimentation, which allows one to study natural phenomena and the physical laws to which the human body is subject;

interest in studying physics and conducting physical experiments;

the ability to independently acquire and apply knowledge;

communication skills that contribute to the development of the ability to work in a group, lead a discussion, and defend one’s point of view.

During the learning process, students acquire the following specific skills:

observe and study phenomena;

describe the results;

calculate errors of direct and indirect measurements;

draw conclusions;

discuss the results of the experiment, participate in the discussion.

The listed skills are formed on the basis of knowledge about:

cycle of knowledge in the natural sciences;

the role of experiment in cognition;

rules for using measuring instruments;

the origin of measurement error and its types;

rules for recording the result of direct measurements, taking into account the error;

Contents of the program.

1. Gorev L.A. Entertaining experiments in physics. M.: Education, 1985.-175 p.

2. Goulridze G.Sh. Practical and laboratory work in physics. Grades 7-11 / edited by N.A. Parsrenteva. - M.: Classic Style, 2002. - 96 p.

3. Raeva A.F. Physical experiment at school. M.: Education, 1973.- 239 p.

4. Burov V. A. Workshop in physics. A manual for students. M.: Education, 1972. – 70 p.

5. Dik Yu. I., Kabardin O. F. et al. Physical workshop for classes with advanced study of physics. M.: Education, 1993. –208 p.

6. Kachinsky A. M., Kimbar B. A. Assignments for laboratory work of a workshop in physics. Minsk: Narodnaya Asveta, 1976. –189 p.

7. Khutorskoy A.V., Khutorskaya L.N. - Fascinating physics: A collection of tasks and experiments for schoolchildren and applicants with answers. –M.: ARKTI, 2001

Theoretical part

Physical parameters of the human body.

The human body and its actions are as interesting for physics as any other natural phenomena and objects around us. Let's consider questions related to the physical properties and characteristics of a person. They can be used to explain various life situations, when discussing a number of problems about the human body.

Get to know yourself, your body, your physical body from the point of view of physics!

Below is unusual information: numbers characterizing the mechanical, thermal, electrical, and optical parameters of a person. These numbers have their own language and can speak about various characteristics of the human body. Their purpose is to help better assimilate, concretize and expand knowledge in physics. They can become assistants in solving various practical issues and problems that may arise in class and at home, and can be useful in preparing messages or essays in the evenings.

Human mechanical parameters.

1) The average density of the human body is 1036 kg/m3.

2) Blood density - 1050-1064 kg/m3.

3) Average speed of blood movement in vessels: in arteries 0.2 - 0.5 m/s; in the veins 0.10 - 0.20 m/s; in capillaries 0.0005-0.0020 m/s.

4) Normal excess pressure in the artery of an adult is measured from a conventional zero, which is taken to be atmospheric pressure. Therefore, a blood pressure of, for example, 9.3 kPa (70 mm Hg) means that it is = 9.3 kPa (70 mm Hg) higher than atmospheric pressure.

Normal lower pressure (i.e. in the initial phase of heart contraction) = 9.3 kPa (70 mm Hg). Normal upper pressure (i.e. in the final phase of heart contraction) is 16.0 kPa (120 mm Hg).

5) Force developed by the beating heart:

in the initial phase of contraction » 90 N;

in the final phase of contraction » 70 N.

6) The mass of blood ejected by the heart in 1 minute is approximately 3.6 kg. In one contraction, the heart releases approximately 60 cm 3 of blood, in 1 minute - 3.6 liters (at 60 contractions per minute), in 1 hour - 216 liters, and in 24 hours >> 5200 liters of blood. During intense work of the body (for example, when skiing), the human heart “pumps” up to 25-35 liters of blood in 1 minute (at 165-196 contractions per minute). For comparison: the water consumption of a fully open water tap in 1 minute is approximately 20 liters.

Heart work during one contraction » 1 J.

Power developed by an adult:

during normal walking on a flat road with a light wind, 60-65 W;

when walking fast (7 km/h) on a flat road with light wind - 200 W;

when riding a bicycle at a speed of 10 km/h in calm weather - 40 W;

when cycling at a speed of 20 km/h in calm weather - 320 W.

Human sound parameters

quiet whisper ≈ 10 -9 W;

speech at normal volume ≈ 7 * 10 -6 W;

maximum volume ≈2 * 10 -3 W;

The frequencies to which the ear is most sensitive are 1500 - 4000 Hz;

Frequency range during normal conversation:

for men - 85-200 Hz;

for women - 160-340 Hz;

bass - 80-350 Hz;

baritone - 110-400 Hz;

tenor - 130-520 Hz;

soprano - 260-1050 Hz;

coloratura soprano - 330-1400 Hz.

bass ≈2.5 cm;

tenor ≈ 1.7-2 cm;

soprano ≈1.5 cm.

The speed of sound in body tissue is 1590-1600 m/s.

The record pitch of a female voice (when singing) is 2.35 kHz.

8) The range of intensity of sounds perceived by the human ear is unusually large: the strongest sounds perceived by the ear (at the threshold of pain)

10-100 W/m 2, differ by 10 13 -10 14 times from the weakest, still perceived sounds (with a hearing threshold of ≈ 10 -12 W/m 2).

Human thermal parameters

Normal body temperature is 36.7°C.

Temperature of individual parts of the body:

forehead - 33.4°C;

palms of hands - 32.8°C;

soles of feet - 30.2 0 C.

The freezing (melting) temperature of blood is from -0.56 ° C to -0.58 0 C.

Specific heat capacity of blood:

3.9 kJ/(kgkK);

0.93 cal/(gk°C).

The mass of water evaporating from the surface of the skin and lungs per day is 0.8-2.0 kg.

The most favorable relative humidity for human life is 40-60%.

Surface tension of blood is 60 mN/m.

Human electrical parameters

1) Specific resistance of body tissues:

muscles - 1.5 Ohm;

blood - 1.8 Ohm;

top layer of skin (dry) - 3.3k10 5 Ohm;

bone (without periosteum) - 2k10 6 Ohm.

2).Dielectric constant:

blood - 85.5;

dry skin - 40-50;

bone - 6-10.

3) The electrical resistance of the human body is determined mainly by the resistance of the surface layer of the skin (epidermis).

The resistance of the human body from the end of one hand to the end of the other with dry, intact skin of the hands = 15 kOhm.

The current strength through the human body, considered safe, is up to 1 mA.

The strength of the current through the human body, leading to serious damage to the body,

≈100 mA.

Safe electrical voltage in a damp room is -12 V.

Safe electrical voltage in a dry room is -36 V.

Human optical parameters

The duration of retention of the resulting visual sensation by the eye is 0.14 s.

The diameter of the eyeball of an adult is 24-25 mm.

The distance between the pupils of the eyes (“base of the eyes”) in an adult is 55-72 mm.

The thickness of the sclera is 0.4-1.0 mm.

The thickness of the choroid is up to 0.35 mm.

The thickness of the retina is 0.1-0.4 mm.

The diameter of the lens is 8-10 mm.

The greatest thickness of the lens is 3.7-4.0 mm.

The refractive index of the lens is ≈1.4.

The focal length of the lens is ≈70 mm.

The optical power of the lens in young people is from 19 to ≈ 33 D.

The refractive index of aqueous and gelatinous humor is -1.34.

The pressure of the clear fluid filling the eye is intraocular pressure ≈104 kPa (= 780 mm Hg).

Pupil diameter:

in high daylight conditions - 2-3 mm;

at low light levels (0.01 lux) - 6-8 mm.

The dimensions of the blind spot (oval shape) are 1.5 to 2.0.

The number of rods in the retina is ≈130 million.

The number of cones in the retina is ≈ 7 million.

The wavelength of light to which the eye is most sensitive is 555 nm (yellow-green rays).

The optical power of the entire eye is ≈ 60 D.

Field of view of a fixed eye:

horizontally - about 160°;

vertically - about 130°.

The minimum size of the image of an object on the retina, at which two points of the object are perceived separately, is 0.002 mm.

Own sizes

It is useful to know your height and stride. The easiest way to measure, for example, the distance traveled is to count the number of steps, but for this you need to know the size of your step.

The size of the step is determined as follows: having measured a straight line on the ground, say 30 m, they walk along it at their normal pace, counting the steps. Dividing 30 by the resulting number of steps, the average length of one step is found. Let's assume that 50 steps fit into a length of 30 m. Dividing 30 by 50, we get:

30: 50 =0.6 m = 60 cm.

This is the width of the average step. To convert the distance measured in steps into meters, you need to multiply the number of steps by the width of one step expressed in meters. For example, there are 630 steps from home to store. The step length is 0.6 m. The distance in meters is 630 0.6 = 378 m.

The span of a person's arms is usually equal to his height. Most often these values ​​coincide, but deviations are, of course, possible. Therefore, it is also useful to check whether your arm span matches your height by measuring.

For approximate measurements of small quantities, it is useful to remember the length of the middle joint of your index finger (Fig. 1), the size of its “quarter” - the distance between the ends of the thumb and little finger of the splayed hand (Fig. 2). Of course, all these methods are very inaccurate, but they are quite suitable for quick approximate measurements in real-life situations.

Draw a segment equal to 0.0001 km, and next to it a segment equal to 0.1 of your ordinary step. Approximately how many steps do you need to take to walk 1 km?

Rice. 1

Fig.2

Qualitative tasks on the topic: “Human Physics”

1.On the sofa.

Why is it softer for a person to lie on a sofa than on a board?

2. Human power.

a) What is the power of a person weighing 75 kg at a normal walking speed of 5 km/h; at a march speed of 7 km/h?

B) What is the power expended when riding a bicycle (at speeds of 9 km/h and

18 km/h)?

c) What power is developed by a person weighing 75 kg who runs up a ladder to a height of 4 m in 2 seconds?

3. How to turn on a swivel chair?

Sit on a swivel chair without your feet touching the floor. You need to turn around on it 360°. How will you do this? Explain your answer.

4. Evaporation of water in the human body.

The human body consists of 65% water. Does it evaporate? How? What does the evaporation process depend on? What does it affect?

5. Man at the bottom of the ocean of air.

Man lives at the bottom of the ocean of air. Why do people usually not feel atmospheric pressure?

6. How does a person breathe?

What is the significance of atmospheric pressure in the mechanism of human pulmonary respiration? What happens when you inhale and exhale air?

7. About black, white and gray colors.

a) What is the difference between white, black and gray colors?

b) How does a person recognize these colors?

Do the following experiment with your friends and draw a conclusion. In a well-darkened room, project a circular spot from a flashlight onto a small white screen. Put out the lantern without the spectators noticing. Instead of a white screen, put a black one and project the same spot onto it, increasing the light intensity of the flashlight several times. The viewer will not notice the replacement of the screen, and will think that he sees the old spot on the old screen. When the light in the room comes on, the viewer notices his mistake and the spot on the screen no longer appears white, but only light.

Why?

8. Grounding.

The electrical connection of an object to the ground is called its grounding. Charges formed on bodies are isolated from the earth; when connected to it, they go into the ground, since due to its large size, compared to any body, the Earth also has a significantly larger capacity. Is it possible to talk about grounding a person?

9. Human biofield.

There are biocurrents and biopotentials in the human body. What it is? Can they be detected?

10. Relative or absolute air humidity?

What is more important for humans: relative or absolute humidity?

11. Dangerous electrical current.

Everyone knows how dangerous electric current can be for a person. For him, a current of 0.1 A is fatal. The current in room wiring is several times stronger than 0.1 A.

Why does it not always strike a person?

12. Sit down - stand up.

Kolya was doing his morning exercises. There were bathroom scales nearby. He decided to do squats by stepping on the scales. To his surprise, when he squatted, the scale showed less weight than when he stood calmly on it. Kolya quickly stood up. The scales, on the contrary, showed an increase in his weight. Kolya repeated these movements several more times. Everything happened again.

Why?

Answers:

1 . The area of ​​contact of the body with the sofa is greater than with the board.

2 . a) About 60 W, or horsepower. As the speed increases, the power increases quickly - 200 watts.

b) When riding a bicycle, the position of the center of gravity of the body changes much less than when walking, and the acceleration of the legs is also less. Therefore, the power consumed when riding a bicycle is significantly less: 30 W; 120 W.

c) 2 horsepower.

3. You need to use your hands. Having turned the outstretched arms to a certain angle in the horizontal plane, the person himself turns in the opposite direction. When the hands stop, the person also stops. In order to turn again in the same direction, you need to return your hands to their original position. This cannot be done by moving your hands in the opposite direction, since the person will also return to the starting position. You can, however, raise your arms in a vertical plane, and then lower them in another vertical plane so that they are in their original position in relation to the person sitting on the chair. A person can turn around a vertical axis an indefinite number of times.

4. During the day, a person, depending on the type of work, evaporates from the surface of the skin and lungs from 800 to 2000 g or more of water. The rate of evaporation processes, and at the same time a person’s well-being, significantly depends on the humidity of the surrounding air. Prolonged stay in hot air, abundantly saturated with water vapor, complicates the evaporation process and at the same time disrupts normal heat exchange in the body. A person feels lethargic and his ability to work decreases.

5. Most organs and tissues in the body contain liquids and gases under pressure approximately equal to atmospheric pressure. The exceptions in this regard are the interpleural space of the chest, the cardiovascular system, cavities filled with cerebrospinal fluid, as well as joint cavities. The communication of these cavities with outside air disrupts the normal functioning of the body.

6. When inhaling, due to the contraction of the corresponding muscles (intercostal and diaphragm), a volumetric expansion of the chest occurs. In this case, the pressure of the air in the lungs becomes lower than atmospheric pressure, and under the influence of the latter, a certain volume of outside air enters (is sucked in) into the lungs. Then the muscles relax, the volume of the chest decreases, the air pressure in the lungs becomes higher than atmospheric pressure, and some of the air in the lungs is forced out. Inhalation occurs. The chest can expand simultaneously in three mutually perpendicular directions: vertical, transverse and anteroposterior.

7. a) The surfaces of very many bodies scatter rays equally from all regions of the visible spectrum. Those of them that scatter a large proportion of the light incident on them are called white. White paper or chalk dissipate up to 90% of the energy falling on them. Those surfaces that scatter rays very weakly are called black. Black photographic paper only scatters about 5% of the light falling on it. Surfaces with intermediate degrees of scattering appear gray to us. Thus, the difference between white, gray and black is not qualitative, but only quantitative, b) Colors are recognized only in comparison with the surrounding illuminated background.

8 The human body as a whole is a conductor, so a person standing on the ground will conduct electrical charges into it, with which he may come into contact. Human contact with the ground under these conditions is also called grounding. If significant electrical charges (or significant electrical current) are passed through a person, this can have dangerous consequences for their health.

9 . Excitation of any organ of the human body is accompanied by the appearance of action currents. The excited site of an organ is always electronegative with respect to the resting sites. A certain potential difference arises between the excited and unexcited areas, and currents flow. These potential differences are small, and the resistance of body tissues is high. Therefore, biocurrents are very weak - about 10 -6 A and less. Their detection is possible using sensitive galvanometers. Biopotentials arise in cells, tissues, and organs due to the uneven distribution of ions K + , Na + , C ++ , Mg ++ , as well as CL - - in the protoplasm of cells and the fluid surrounding the cell. This is due to the metabolic processes occurring in living cells. Biopotentials reflect the functional state of organs and tissues in normal and pathological conditions, which is used in the diagnosis of diseases. Common methods for recording the potentials of the heart - electrocardiography, the brain - electroencephalography, peripheral nerve trunks and muscles - electromyography.

10 . In different cases, both absolute and relative humidity can be important. For example, the evaporation of water from the surface of the skin depends on relative humidity, so the greater the difference between absolute and maximum humidity (the amount of steam per g saturating 1 m 3 of air at a given temperature), the faster evaporation occurs. When considering the evaporation of water by the lungs, one should take into account the absolute humidity of the air, since air is exhaled from the lungs, almost completely saturated with steam, at a temperature of approximately 30°C. The amount of steam with which the air is saturated in the lungs obviously depends on the absolute humidity of the inhaled air. An atmosphere with a relative humidity of 40 to 60% is considered normal for human life.

11. The current strength in the lighting network reaches 0.5 A, but only until the human body is included in the circuit. Turning on the latter significantly reduces the current strength, since the resistance of our body is very high: it ranges from 100 to several tens of thousands of ohms. The introduction of such a significant resistance into the circuit naturally reduces the current strength in it, and the current becomes almost harmless to the body. Sometimes even 5000 V does not cause any harm to a person - the resistance of the human body is sometimes so great. But it fluctuates depending on many reasons that cannot be foreseen: humidity, body size, even our mood, so the voltage of the electrical network, which is harmless today, can be fatal tomorrow.

12. Kolya’s body partially experienced the phenomenon of weightlessness (during a quick squat) and overload (during a quick rise, the body puts more pressure on the support).

ERROR ASSESSMENT

WHEN MEASUREING PHYSICAL

SIZE

To measure a physical quantity means to compare it using measuring instruments with a homogeneous quantity taken as a unit, and to evaluate the degree of its approximation to the true value.

Currently, the generally accepted International System (SI), which is based on seven basic units:

length - meter (m);

mass - kilogram (kg);

time - second (s);

electric current - ampere (A);

temperatures - kelvin (K);

luminous intensity - candela (cd);

amount of substance - mole.

To ensure the uniformity of physical measurements, international standards for each of the basic SI units have been created.

If they use quantities that are multiples of the basic units, they use the corresponding prefixes taken from the ancient Greek language; if quantities subordinate to basic units are used, the corresponding prefixes taken from the Latin language are used.

Measurements are divided into direct and indirect. A direct measurement is one in which the result is found when read from the instrument scale. Indirect measurement is a measurement in which the result is found based on calculations.

The true value of the measured value cannot be determined for many reasons and, above all, because the reproduction of the standard is limited. Magnitude A is considered measured if not only the value itself is indicated A change , but also the limit of its absolute error ∆A

A = A change , ± ∆A

The quality of measurements is determined by the relative error ε:

ε = *100%.

The error of direct measurement ∆A consists of the error of the measuring instrument ∆A inc and the error of reading ∆A count:

∆A = ∆A inc + ∆A count

The reading error is equal to, or rather not more than, half of the scale division:

∆ A profit =

Where A- scale division price.

When carrying out repeated measurements of a physical quantity, slightly different results are obtained. In this case, the arithmetic mean of the results of individual measurements must be taken as the measurement result:

experimental part

Laboratory work No. 1

DETERMINING THE VOLUME AND DENSITY OF YOUR BODY.

Goal of the work: learn to determine the density and volume of your body.

Progress:

1.Measure the average length ℓ(m) and widthb (m) baths in your apartment.

2. Pour warm water into the bath and mark its level with a pencil.

3. Immerse yourself in the water and note its new level. Measure the lift height

water ∆ h (m).

4. Find the volume of displaced water, and therefore the volume of the bodyV T(excluding

head volume): V T =ℓ * b * ∆ h.

The shape of the bathtub may differ noticeably from a parallelepiped, so the volume of displaced water can be more accurately determined experimentally by adding water with a bucket (a soda bottle or other container of known volume) to the mark you made.

5. In order to take into account the volume of the head, measure the diameter of the headd(m) and, considering it a ball, calculate the volume:

V G = π d 3

6. Calculate the total volume of your body (m3): V generally = V T + V G

7. Measure your body weight m(kg) using a scale.

8. Find the density ρ(kg/m3) of your body: =

Additional task:

Compare the density of your body with the density of water and answer the questions:

Why can a person stay on the surface without moving?

Why is it easier to swim in sea water?

Laboratory work No. 2

DETERMINING THE AVERAGE STEP LENGTH.

Goal of the work: learn to determine the average length of your step.

Laboratory work No. 3

DETERMINING THE FORCE OF ATMOSPHERE PRESSURE ON YOUR BODY

Goal of the work: Learn to determine the force of atmospheric pressure on your body.

Equipment: barometer, floor scales, stadiometer.

F atm = p atm * S.

Fill the table:

p atm,Pa

Laboratory work No. 4

“Determination of arm strength when performing exercises on the horizontal bar.”

Hang on the bar in the gym with one arm for a while, feel the tension in the muscles of your arm.

Measure your body weight on a scale T and calculate gravity F T (H) acting on it.

To determine your body volume V generally take advantage of the result of work already completed.

Find the buoyant force F a (H), acting on your body from the air:

where ρ = 1.3 kg/m 3 - air density and show that the buoyant force of air is slightly more than 0.1% of the force of gravity acting on you, and therefore F A is usually neglected.

5. Find the force F p with which your hand acts on the crossbar:

F p =F t -F a F t

Fill the table:

t, kg

Laboratory work No. 5

"Measurement of power developed when climbing stairs."

Equipment: weight on a cord, stopwatch, bathroom scales, tape measure.

Having lowered a weight on a strong cord down the flight of stairs, make a mark on it when the weight reaches the floor of the first floor. Measure the height of the stairs h(m).

Use a stopwatch to determine the time t(c) it took you to climb the stairs.

Measure your body weight m(kg).

Calculate Power N(W) developed during ascent:

Fill the table:

h(m)

Defense and discussion of research results.

Students must present the results of research on the physical parameters of their body. Analyze the results. Prepare a defense of the theoretical part of the work for one of the laboratory works.

With your feet resting on the globe,
I hold the ball of the sun in my hands.
I am like a bridge between the Earth and the Sun,
And for me the Sun descends to Earth,
And the Earth rises towards the Sun.
So I stand...I, Man.

E. Mezhelaitis

Many sciences study man: philosophy, history, anthropology, biochemistry... etc. But only by considering the human phenomenon holistically will we be able to formulate an answer to the question: “What is a person?”

How does our body work?
How does he work?
What's good for your health?

What is life-threatening?
Let's try to rummage through the literature and figure it out!
Do you know about the interesting features of our body?

Human DNA contains about 80,000 genes.
In ancient Rome, people lived on average no more than 23 years, and in the 19th century in the United States, the average life expectancy did not exceed 40 years.
Men are considered dwarfs if their height is below 130 cm, women - below 120 cm.
The human body consists of 639 muscles.
When a person smiles, 17 muscles “work.”
In the human spine 33 or 34 vertebrae.
At birth, a child’s body contains about 300 bones; by adulthood, only 206 remain.
Almost half of all human bones are found in the wrists and feet.
Fingernails grow approximately 4 times faster, than on your feet.
Human bones are 50% water.
Each human finger bends approximately 25 million times during a lifetime.
The human body contains only 4 minerals: apatite, aragonite, calcite and cristobalite.
Children are born without kneecaps. They appear only at the age of 2-6 years.
The human eye is capable of distinguishing 10,000,000 shades of color.
The phenomenon in which a person loses the ability to see due to strong light is called “snow blindness.”
On average, you secrete 5 milliliters of tears - that's a large bottle in a year.
By blinking 20 times a minute, you moisturize your eyes.
This amounts to more than 10 million muscular contractions per year.
It is impossible to sneeze with your eyes open.
Women blink approximately 2 times more often than men.
Men are about 10 times more likely than women to suffer from color blindness. People with blue eyes more sensitive
to pain than everyone else. A person blinks on average every 6 seconds, which means that throughout our lives we lower and raise our eyelids about

250 million times.
On average, human hair grows at a rate of 12 mm per month.
Blondes grow a beard faster than brunettes.
Human hair is approximately 5,000 times thicker than soap film.
At rest, you inhale and exhale 16 times per minute, during which time 8 liters of air pass through your lungs. In a year, this amount of air could fill two balloons.
The surface of the lungs is about
100 square meters.
The right lung of a person holds more air than the left. An adult takes approximately 23,000 breaths (and exhalations) per day.
The surface area of ​​human lungs is approximately equal to
tennis court area.
The strongest muscle in the human body is the tongue.
There are about 2000 taste buds in the human body.
There are about 40,000 bacteria in the human mouth.
The average human brain weighs about 1.3 kg.
The human brain generates more electrical impulses per day than all the world's phones combined.
From the moment of birth, there are already 14 billion cells in the human brain, and this number does not increase until death. On the contrary, after 25 years it decreases by 100 thousand per day.
In the minute you spend reading a page, about 70 cells die.
After 40 years, brain degradation accelerates sharply, and after 50, neurons (nerve cells) dry out and brain volume decreases.
In the human brain, 100,000 chemical reactions occur in one second.
Man is the only representative of the animal world capable of drawing straight lines.
The length of hair on the head grown by the average person during a lifetime is 725 kilometers.
Young skin contains an incredible amount of water - 8 liters.
Every day you lose up to 2 liters through your skin. Since the process of skin cell death takes 120 days, this means you change your skin three times in a year.
During a lifetime, a person's skin changes approximately 1000 times.
Your heart beats 80 times per minute at rest, pumping 5 liters of blood.
In a year, the heart makes 42 million contractions and pumps enough blood to fill several swimming pools.
36,800,000 - the number of heartbeats in a person in one year.
The size of a person's heart is approximately equal to the size of his fist.
The weight of an adult human heart is 220-260 g. Nerve impulses in the human body move at a speed of approximately 90 meters per second.
There are about 75 kilometers (!) of nerves in the adult human body.
Human gastric juice contains 0.4% hydrochloric acid(HCl).
Humans have approximately 2 million sweat glands. The average adult loses 540 calories with every liter of sweat.
Men sweat about 40% more than women.
During life, the human small intestine is about 2.5 meters long.
After his death, when the muscles of the intestinal wall relax, its length reaches 6 meters.
The total weight of bacteria living in the human body is 2 kilograms.
A person is able to recognize only five odors: floral, specific (lemon, apple, etc.), burnt (coffee, etc.), rotten (rotten eggs, cheese, etc.) and ethereal (gasoline, alcohol) .
A person who gets lost during thick fog or a blizzard almost always walks in a circle, which is explained by the asymmetry of our body, that is, the lack of complete balance between the right and left halves of the human body.
A person, it turns out, trembles only to keep warm.
A person who smokes a pack of cigarettes a day drinks half a cup of tar a year.

How does a person tolerate different altitudes above sea level?

The death zone is more than 8 km: a person can stay at this altitude without a breathing apparatus for only a short time - 3 minutes, and at an altitude of 16 km - 9 seconds, after which death occurs.
Critical zone - from 6 to 8 km: serious functional disorders of the body.
Zone of incomplete compensation - from 4 to 5 km: deterioration in general well-being.
The zone of full compensation is from 2 to 4 km: some disturbances in the activity of the heart, sensory organs and other systems, thanks to the mobilization of the body's reserve forces, quickly disappear.
The safe zone is from 1.5 to 2 km: there are no significant disruptions in the functioning of the human body.

Temperatures that are critical for the human body
(at normal pressure and relative humidity)

Normal temperature for most people is from 36.3 to 37C
Critical temperature accompanied by loss of consciousness - above 42C
Lethal temperature - above 43C
Temperature leading to a slowdown in brain processes - below 34C
Critical temperature accompanied by loss of consciousness - below 30C
Lethal temperature, cardiac fibrillation occurs, blood circulation stops - below 27C

Basic physical parameters of blood.

All parameters are given for body temperature - 37C
Density - 1050 kg/cub.m
Viscosity - 0.004 Pa.s
Blood plasma viscosity - 0.0015 Pa.s
Hemoglobin diffusion coefficient in water - 0.00000000007 sq.m.
Surface tension 0.058 N/m
Freezing (melting) temperature - minus 0.56C
Specific heat capacity - 3000 J/kg.K

Electrical characteristics of human body tissues

Resistivity:
...muscles - 1.5 Ohm.m
...blood - 1.8 Ohm.m
...leather - №№0000 Ohm.m
...bone - 1000000 Ohm.m

...blood -85.5
...skin - from 40 to 50
...bone - from 6 to 10

Heat transfer from the human body

Loss of energy from the total balance:
...for respiration and evaporation of water - 13%
...on the work of internal organs and systems - 1.87%
...for heating exhaled air - 1.55%
...for the evaporation of water from the surface of the skin - 20.7%
...for heating the surrounding space - 30.2%
... for radiation - 43.8%

Human mechanical parameters

The average density of a person is 1036 kg cubic m
Average blood speed:
...in arteries - from 0.2 to 0.5 m s
...in the veins - from 0.1 to 0.2 m s
The speed of spread of irritation along the nerves is from 400 to 1000 m s
Force developed by the beating heart:
...in the initial phase of contraction - 90 N
...in the final phase of contraction - 70N
Heart work per day - 86400 J
The mass of blood ejected by the heart per day is 5200 kg
Power developed during fast walking - 200 W

Human electrical parameters

Specific resistance of body tissues:
...top layer of dry skin - 330000 Ohm.m
...blood - 1.8 Ohm.m
...muscles - 1.5 Ohm.m
The dielectric constant:
...dry skin - from 40 to 50
...blood - 85
Human resistance from the end of one hand to the end of the other (with dry skin) - 15000 Ohms
Current flow through the human body:
...safe - less than 0.001 A
... life-threatening - more than 0.05 A
Safe electrical voltage:
...dry room - less than 12 V
...damp room - less than 36 V

Human optical parameters

Duration of retention of visual sensation by the eye - 0.14 s
The diameter of the eyeball of an adult is 25 mm
Refractive index of the lens - 1.4
Optical power:
...lens - from 19 to 33 diopters
...total eyes - 60 diopters
Pupil diameter:
...in daylight - 2 mm
...in night lighting - from 6 to 8 mm
Intraocular pressure - 104 kPa (780 mm Hg)
The number of rods in the retina is 130 million
The number of cones in the retina is 7 million
The minimum size of the image on the retina at which two points of an object are perceived separately is 0.002 mm
The wavelength of light to which the eye is most sensitive is 555 mm

Human radiation parameters

Permissible radiation dose - up to 0.25 Gy
Radiation dose causing radiation sickness - from 1 to 6 Gy
Lethal dose of radiation - from 6 to 10 Gy

“All bodies, the firmament, the stars, the Earth and its kingdoms cannot be compared with the lowest of minds, for the mind carries within itself the knowledge of all this, but the bodies know nothing.”

The mechanical work that a person is capable of doing during the day depends on many factors, so it is difficult to indicate any limit value. This remark also applies to power. Thus, with short-term efforts, a person can develop a power of the order of several kilowatts. If an athlete weighing 70 kg jumps from a place so that his center of mass rises 1 m relative to the normal stance, and the take-off phase lasts 0.2 s, then he develops a power of about

When walking, a person does work, since in this case energy is spent on periodically slightly raising the body and on accelerating and decelerating the limbs, mainly the legs.

A person weighing 75 kg, walking at a speed of 5 km/h, develops a power of about 60 W. As speed increases, this power increases rapidly, reaching 200 W at 7 km/h. When riding a bicycle, the position of a person's center of mass changes much less than when walking, and the acceleration of the legs is also less. Therefore, the power consumed when cycling is significantly less: 30 W at 9 km/h, 120 W at 18 km/h.

The work goes to zero if there is no movement. Therefore, when the load is on a support or stand or suspended from a thread, gravity does no work. However, each of us is familiar with the fatigue of the arm and shoulder muscles when holding a kettlebell or dumbbell motionless at arm's length. In the same way, the muscles of the back and lumbar region become tired if a load is placed on the back of a sitting person. In both cases, the load is motionless and there is no work. Fatigue indicates that the muscles are doing work. This kind of work is called static muscle work.

There really is no statics (immobility) as it is understood in mechanics. Very small and frequent contractions and relaxations, invisible to the eye, occur, and at the same time work is done against the forces of gravity. Thus, a person's static work is actually ordinary dynamic work.

To measure human performance, instruments called ergometers. The corresponding section of measuring technology is called ergometry.

An example of an ergometer is a brake bicycle (bicycle ergometer; Fig. 4.1). A steel strip is thrown over the rim of the rotating wheel 2. The friction force between the tape and the wheel rim is measured by dynamometer 3. All the work of the subject is spent on overcoming the friction force (we neglect other types of work). By multiplying the circumference of the wheel by the friction force, we will find the work done at each revolution, and knowing the number of revolutions and test time, we will determine the total work and average power.

In the physics course studied in modern schools, practically no attention is paid to the physical parameters that characterize a person. However, in connection with the study of psychological issues in school, modeling of processes occurring in living organisms, in technology, and the development of such a science as bionics, students are increasingly showing increased interest in the study of human physics.

While studying this course, students will not only satisfy their educational needs, but also gain research skills, become familiar with research methods in physics and biology, and receive brief information about medical and biological equipment. The skills acquired while working with measuring instruments, performing practical work and setting up experiments will be useful in further scientific and technical activities. An explanation of individual processes occurring in living organisms on the basis of physical laws will help them establish cause-and-effect relationships that exist in living and inanimate nature, and will generate interest not only in physics, but also in biology.

The course program is practice-oriented with elements of research activities. This elective course can be used for teaching in classes with biological, chemical or medical profiles.

Studying the elective course is designed for 17 hours, of which 7.3 hours (43%) are devoted to studying theoretical issues, 9.7 hours (57%) are practical classes (solving problems, performing laboratory work).

Main objectives of the course:

• Show students the unity of the laws of nature, the applicability of the laws of physics to a living organism, the promising development of science and technology, and also show in which areas of professional activity the knowledge gained in the special course will be useful to them.
• Create conditions for the formation and development of intellectual and practical skills among students in the field of physical experimentation.
• Develop cognitive activity and independence, the desire for self-development and self-improvement.

Course objectives:

• To promote the formation of cognitive interest in physics and the development of creative abilities in students.
• Develop students' intellectual competence.
• Develop skills in performing practical work and conducting research activities.
• Improve skills in working with reference and popular science literature.

Upon completion of the course, students must

• know:
  • what physical laws can be used to explain the processes occurring in the human body;
  • features of your body from the point of view of the laws of physics.
• be able to:
  • work with various sources of information;
  • observe and study phenomena, describe the results of observations;
  • model phenomena, select the necessary instruments, perform measurements, present measurement results in the form of tables, graphs, set research problems.

Main course content

The content of the course is qualitatively different from the basic physics course. In lessons, the laws of physics are discussed mainly in inanimate objects. However, it is very important that students gradually develop the conviction that the cause-and-effect relationship of phenomena is universal in nature and that all phenomena occurring in the world around us are interconnected. The course examines issues aimed at developing interest in physics, experimental activities, and developing the ability to work with reference literature. Upon completion of the course, students draw up a “Physical Passport of a Person.”

Human mechanical parameters– 10 o’clock

Physics. Human. Biophysical research in physics. Linear dimensions of various parts of the human body, their mass. Density of liquids and solid tissues that make up a person.
Kinematic quantities and the human body.
Movement of a body in a gravity field. Free fall. Human reaction time. The motion of a body thrown at an angle to the horizontal.
Newton's first law. Inertia in living nature. Newton's second law. Determination of human strength. Dynamics of muscle tissue. Newton's third law.
The human body in the gravitational field of the earth. Conditions for long-term human existence on a space station. Measures to protect pilots and astronauts from acceleration. Weightlessness and overload.
Upright posture and the human musculoskeletal system. Walking man. Types of joints. Deformation of bones, tendons, muscles. Strength of biological materials. The structure of bones from the point of view of the possibility of greatest deformation.
The manifestation of friction force in the human body, natural lubrication. Braking distances.
Pressure. Atmosphere and people. Breath. Fluid pressure. Blood pressure. Laws of blood movement in the human body.
Maintaining balance by living organisms. Center of gravity of the human body. Levers in the human body.
Work and power developed by a person in different types of activities. "Energy" and human development. Application of the law of conservation of energy to certain types of human movement.
The role of atmospheric pressure in human life. Osmotic pressure. Changes in blood pressure in the capillaries. Respiratory system.
Laboratory works.

• Carrying out anthropological measurements
• Determine the average speed of movement.
• Determination of human reaction time.
• Calibration of a dynamometer and determination of a person’s back strength.
• Determination of the coefficients of friction of human shoe soles on various surfaces.
• Determination of power developed by a person.

Oscillations and waves in living organisms– 2 hours

Oscillations and man. Origin of biorhythms. Heart and sounds accompanying the work of the heart and lungs, their recording.
Sound as a means of perception and transmission of information. Organ of hearing. Ultrasound and infrasound. Sound audibility range. Human vocal apparatus. Characteristics of the human voice.
Laboratory work.

• Determination of the tidal volume of a person's lungs.
• Carrying out instrumental measurements and functional tests.
• Pulse counting before and after dosed exercise.
• Study of the properties of the ear.

Thermal phenomena– 1 hour

Thermoregulation of the human body. Humidity. Respiratory system. Thermal processes in the human body. Man is like a heat engine. Laboratory work.

• Calculation of energy costs and determination of calorie intake

Electricity and magnetism– 2 hours

Electrical properties of the human body. Bioelectricity. Bacteria are the Earth's first electricians. Photoreceptors, electroreceptors, sleep bioelectricity. Electrical resistance of human organs to direct and alternating current.
Man in the world of electromagnetic radiation.
Laboratory work.

• Determination of human tissue resistance to direct and alternating electric current.

Human optical parameters – 1 hour

The structure of the human eye. The power of accommodation of the eye. Optical power. Visual defects and ways to correct them. Features of human vision. Resolution power of the human eye. How is it that we see. Why do we need two eyes? Spectral and energy sensitivity of the eye.
Laboratory work.

• Observation of some psychophysiological features of human vision.
• Determination of characteristic parameters of human vision.
• Determination of the spectral limits of sensitivity of the human eye.

Student certification system. After completing the course, credit is given if the following conditions are met:

• Active participation in the preparation and conduct of seminars, conferences, publication of newspapers, and production of models.
• Completion of at least half of laboratory work.
• Completion of at least one experimental task of a research or design nature.
• Drawing up a “Physical Passport of a Person”.

Thematic course planning

No.	Lesson topic	Number of hours
		Total	theory	practice
Human mechanical parameters (10 h)
1.	Physics. Human. Environment.
2.	Kinematics and the human body.
3.	Movement of a body in a gravity field.
4.	Newton's laws in human life.
5.	Gravity and man.
6.	Upright posture and the human musculoskeletal system.
7.	Manifestation of friction force in the human body.
8.	Work and power developed by a person in different types of activities.
9.	Statics in the human body.
10.	Pressure and the human body.
Oscillations and waves in living organisms (2 hours)
11.	Oscillations and man.
12.	Sound.
Thermal phenomena (1 hour)
13.	Thermal processes in the human body.
Electricity and magnetism. (2 hours)
14.	Electrical properties of the human body
15.	Man in the world of electromagnetic radiation.
Human optical parameters (1 hour)
16.	Eye and vision
17.	Conference.
	Total:

The first group includes: the weight of individual parts of the human body, density, modulus of elasticity and shear modulus of soft and hard tissues of the body, the speed of propagation of stress waves in tissues and their characteristic impedances. [...]

The second group of derived characteristics consists of: indicators of the relative damping of oscillations as they propagate throughout the body from the point of excitation, frequency characteristics of input mechanical impedances in the area of ​​contact of the body with vibrating surfaces, transient mechanical impedances for any point on the surface of the body, frequencies of natural oscillations of body structures.[ ...]

Note. Weight of hand 0.6 kg, forearm 1.6 kg, shoulder 2.3 kg.[...]

In table Figure 4 shows the weights of individual parts of the human body averaged according to the data of N.N. Khavkin, Coldman (cited by Harris and Crede, 1961) and Woodson and Conover (1968), relative to the total weight and in absolute values. The latter refer to the average for men with a height of 175 cm and a weight of 70 kg.[...]

In table 6, based on the same literary sources, shows the average changes in stiffness K and dissipative resistance R of soft tissues of the body when they are displaced under the influence of a static load per area of ​​1 cm2.[...]

These data were obtained by Franke (cited by Harris and Crede, 1961) on only two subjects and were characterized by scattering of readings. Nevertheless, it can be seen that under loads causing tissue displacements not exceeding 5 mm, the stiffness K and resistance R change almost linearly with the change in load. At displacements of more than 5 mm, body tissues exhibit a characteristic nonlinearity of their elastic-viscous properties.[...]

Of the derivative mechanical characteristics of the human body, let us first consider the damping of vibrations as they propagate throughout the body from the point of excitation. This attenuation for a frequency of 50 Hz was first studied in 1939 by Vökevu.[...]

For us, the study of the attenuation of oscillations as they propagate throughout the human body was of interest in a slightly different aspect, namely in comparing the characteristics of the attenuation of oscillations of various frequencies under the influence of vibration through the feet or palms in order to clarify the concepts of “local” and “general” vibrations and to determine the size of the receptive zone covered by the oscillatory movement.[...]

We also conducted studies on 10 practically healthy men (ten experiments each) in the frequency range from 8 to 125 Hz and under the influence of vibrations on the feet and palms. The source of vibrations was a mechanical vibration stand VUS-70/200. The subject either stood on the platform of the stand, or, being outside it, pressed from top to bottom on a vibrating handle attached to the platform, monitoring the specified pressure force using a pointer device. The propagation of vibrations was recorded by measuring equipment from Brühl & Co. with a 30-gram sensor pressed by the tester’s hand to the bone protrusions at fixed points of the body. The measured levels of oscillatory velocity were averaged with the determination of standard deviations, which fluctuated within ±2-5 dB.[...]

We studied the influence of muscle tension on the conductivity of vibration by the tissues of the hand by measuring the intensity of vibration at the same points - on the subjects' shoulder - under conditions of the same level of oscillatory velocity in the contact zone with the vibrating surface, but with different pressure forces on the handle.[...]

Tables for this chapter: