VII urban scientific – practical conference"Step into the future"

Measurement history and simple DIY measuring instruments

Completed: Evgeniy Antakov, student of MBOU Secondary School No. 4,

Scientific supervisor: Osiik T.I. primary school teacher MBOU Secondary School No. 4, Polyarnye Zori

My name is Antakov Zhenya, I 9 years.

I'm in third grade, I do swimming, judo and English.

I want to become an inventor when I grow up.

Project goal: - study the history of measurements of time, mass, temperature and humidity and simulate the simplest measuring instruments from scrap materials.

Hypothesis : I suggested that the simplest measuring instruments can be modeled independently from available materials.

Project objectives :

- study the history of measurements of various quantities;

Familiarize yourself with the design of measuring instruments;

Model some measuring instruments;

Identify Opportunity practical application homemade measuring instruments.

Scientific article

1. Measuring length and mass

People have been faced with the need to determine distances, lengths of objects, time, areas, volumes and other quantities since ancient times.

Our ancestors used their own height, arm length, palm length, and foot length as means of measuring length.

To determine long distances, the most various ways(flight range of arrows, “tubes”, beeches, etc.)

Such methods are not very convenient: the results of such measurements always vary, since they depend on the size of the body, the strength of the shooter, vigilance, etc.

Therefore, strict units of measurement, standards of mass and length gradually began to appear.

One of the oldest measuring instruments is scales. Historians believe that the first scales appeared more than 6 thousand years ago.

The simplest model of scales - in the form of an equal-arm beam with suspended cups - was widely used in Ancient Babylon and Egypt.

Organization of the study

• Rocker scales from a hanger

In my work, I decided to try to assemble a simple model of cup scales, with which you can weigh small objects, products, etc.

I took an ordinary hanger, secured it on a stand, and tied plastic cups to the hangers. The vertical line indicated the equilibrium position.

To determine mass, you need weights. I decided to use regular coins instead. Such “weights” are always at hand, and it is enough to determine their weight once in order to use it for weighing on my scales.

5 rub

50 kopecks

10 rub

1 rub

Organization of the study

Experiments with rocker scales

1. Scale scale

Using different coins, I made marks on a piece of paper corresponding to the weight of the coins

2. Weighing

Handful of candy - balanced using 11 different coins, total weight 47 grams

Check weighing – 48 grams

Cookies - balanced with 10 coins weighing 30 grams On control scales - 31 grams

Conclusion: from simple objects I assembled scales with which you can weigh with an accuracy of 1-2 grams

Scientific article

2.Measurement time

In ancient times, people felt the passage of time according to

the change of day and night and seasons and tried to measure it.

The very first instruments for telling time were sundials.

In ancient China, to determine time intervals, a “clock” was used, which consisted of an oil-soaked cord on which knots were tied at regular intervals.

When the flame reached the next node, it meant that a certain period of time had passed.

Candle clocks and oil lamps with marks operated on the same principle.

Later, people came up with the simplest devices - hourglasses and water clocks. Water, oil or sand flows evenly from vessel to vessel, this property allows you to measure certain periods of time.

With the development of mechanics in the 14th and 15th centuries, clocks with a winding mechanism and a pendulum appeared.

Organization of the study

• Water clock made from plastic bottles

For this experiment, I used two 0.5 liter plastic bottles and cocktail straws.

I connected the lids together using double-sided tape and made two holes into which I inserted the tubes.

I poured colored water into one of the bottles and screwed on the caps.

If the entire structure is turned over, the liquid flows down through one of the tubes, and the second tube is necessary for air to rise into the upper bottle

Organization of the study

Experiments with water clocks

The bottle is filled with colored water

Bottle filled with vegetable oil

Liquid flow time – 30 seconds Water flows quickly and evenly

Liquid flow time – 7 min 17 sec

The amount of oil is selected so that the liquid flow time is no more than 5 minutes

A scale was applied to the bottles - marks every 30 seconds

The less oil there is in the top bottle, the slower it flows down, and the distances between the marks become smaller.

Conclusion: I got a watch that can be used to determine time intervals from 30 seconds to 5 minutes

Scientific article

3. Temperature measurement

A person can distinguish between heat and cold, but does not know the exact temperature.

The first thermometer was invented by the Italian Galileo Galilei: a glass tube is filled with more or less water depending on how much the hot air expands or the cold air contracts.

Later, divisions, that is, a scale, were applied to the tube.

The first mercury thermometer was proposed by Fahrenheit in 1714; he considered the freezing point of the saline solution to be the lowest point

The familiar scale was proposed by the Swedish scientist Andres Celsius.

The lower point (0 degrees) is the melting temperature of ice, and the boiling point of water is 100 degrees.

Organization of the study

• Water thermometer

The thermometer can be assembled using a simple scheme from several elements - a flask (bottle) with colored liquid, a tube, a sheet of paper for a scale

I used a small plastic bottle, filled it with tinted water, inserted a juice straw, and secured everything with a glue gun.

While pouring the solution, I ensured that a small part of it fell into the tube. By observing the height of the resulting liquid column, one can judge the temperature changes.

In the second case, I replaced the plastic bottle with a glass ampoule and assembled the thermometer using the same scheme. I tested both devices under different conditions.

Organization of the study

Experiments with water thermometers

Thermometer 1 (with plastic bottle)

The thermometer was placed in hot water - the liquid column dropped down

The thermometer was placed in ice water - a column of liquid rose up

Thermometer 2 (with glass bulb)

The thermometer was placed in the refrigerator.

The column of liquid has dropped down, the mark on a regular thermometer is 5 degrees

The thermometer was placed on the heating radiator

The column of liquid has risen upward; a regular thermometer shows 40 degrees

Conclusion: I received a thermometer that can be used to roughly estimate the ambient temperature. Its accuracy can be improved by using a glass tube with the smallest possible diameter; fill the flask with liquid so that there are no air bubbles left; use an alcohol solution instead of water.

Scientific article

4. Humidity measurement

An important parameter of the world around us is humidity, since the human body reacts very actively to its changes. For example, when the air is very dry, sweating increases and a person loses a lot of fluid, which can lead to dehydration.

It is also known that in order to avoid respiratory diseases, the air humidity in the room should be at least 50-60 percent.

The amount of humidity is important not only for humans and other living organisms, but also for the flow of technical processes. For example, excess humidity can affect the correct operation of most electrical appliances.

To measure humidity, special instruments are used - psychrometers, hygrometers, probes and various devices.

Organization of the study

Psychrometer

One way to determine humidity is based on the difference in the readings of “dry” and “wet” thermometers. The first shows the temperature of the surrounding air, and the second shows the temperature of the damp cloth with which it is wrapped. Using these readings using special psychrometric tables, the humidity value can be determined.

I made a small hole in a plastic shampoo bottle, inserted a string into it, and poured water into the bottom.

One end of the lace was secured to the flask of the right thermometer, the other was placed in a bottle so that it was in water.

Organization of the study

Experiments with a psychrometer

I tested my psychrometer by determining humidity in various conditions

Near a heating radiator

Near a running humidifier

Dry bulb 23 º WITH

Wet bulb 20 º WITH

Humidity 76%

Dry bulb 25 º WITH

Wet bulb 19 º WITH

Humidity 50%

Conclusion: I found out that a psychrometer assembled at home can be used to assess indoor humidity

Conclusion

The science of measurements is very interesting and diverse; its history begins in ancient times. Exists huge amount various methods and measuring instruments.

My hypothesis was confirmed - at home you can simulate simple instruments (yoke scales, water clock, thermometer, psychrometer) that allow you to determine weight, temperature, humidity and specified periods of time.

Homemade instruments can be used in everyday life if you do not have standard measuring instruments at hand:

Time yourself doing abdominal exercises, push-ups, or jumping rope

Keep track of time when brushing your teeth

In class, conduct five-minute independent work.

References.

1. “Meet, these are... inventions”; Encyclopedia for children; publishing house "Makhaon", Moscow, 2013

2. “Why and why. Time"; Encyclopedia; publishing house "World of Books", Moscow 2010

3. “Why and why. Inventions"; Encyclopedia; publishing house "World of Books", Moscow 2010

4. “Why and why. Mechanics; Encyclopedia; publishing house "World of Books", Moscow 2010

5. “Big Book of Knowledge” Encyclopedia for children; publishing house "Makhaon", Moscow, 2013

6. Internet site “Entertaining-physics.rf” http://afizika.ru/

7. Website “Watches and Watchmaking” http://inhoras.com/

Alekseenko Alina

Project Manager:

Gorobtsova Galina Stepanovna

Institution:

MBOU Lyceum No. 1 of Proletarsk

In individual student physics project on the topic “Physical devices around us” a definition was given to simple physical instruments with a measurement scale used in everyday life to measure a physical quantity, for example, a barometer, thermometer, watch.

More details about the work:

Within research paper in physics about physical instruments the history and design of sundials and scales were analyzed, historical and theoretical information on the measurement of physical quantities was reviewed, and experiments were conducted to apply the acquired knowledge in practice.

Materials for this project in physics " Physical devices around us"contains the author's own research on the use of scale instruments for measuring physical quantities in everyday life and their competitiveness in relation to electronic measuring instruments.

Introduction
1. Simple physical devices.
2. History of the thermometer.
Conclusion
Literature

Introduction

Relevance of the study: In the 20th century, only professionals could use scale measuring instruments. But with the development of science and technology, the number of electronic measuring instruments in a person’s daily life is rapidly increasing: in my mother’s kitchen, in my father’s garage, in my new cell phone.

Project hypothesis: I assume that, although modern measuring instruments are mostly electronic, there are and will be scale instruments.

Purpose of the work: systematize knowledge about school and other measuring instruments, using historical and local history educational material.

Project objectives

1. Study additional literature on the topic of the project
2. Conduct experiments to confirm the theory
3. Systematize theoretical knowledge and experimental results
4. Design the multimedia product of the project

Simple physical devices

Meter- a measuring instrument designed to obtain the values ​​of the measured physical quantity.

In everyday life: at home or at school, we often encounter a variety of measuring instruments

All measuring instruments have one common property: each of them has a scale.

Scales- this is a device for determining the mass of bodies (weighing) by the weight acting on them, approximately counting it equal strength gravity. As historical information It can be noted that the first samples of scales found by archaeologists date back to the 5th millennium BC. e., they were used in Mesopotamia.

On the presented slide you can see the most different scales, but at school, in the classroom, to determine the mass of physical bodies, we use lever scales, where at the initial stage it is necessary to balance the scales, and remember that we place a weight on the left pan of the scale, and weights on the right pan, which can have a measure in grams , and in milligrams. Milligram weights are small in size and flat in shape and therefore require the use of special tweezers to use them.

At home, we use either vertical spring scales to measure masses up to 15-20 kg, or electronic scales(g, mg)

Steelyard simple lever scales. Russian steelyard (kontary, kantar) - a metal rod with a constant load at one end and a hook or cup for the object being weighed at the other.

The steelyard is balanced by moving the second hook of the cage or loop along the rod, which serves as a support for the steelyard rod. " Due to the imperfection of the steelyard and the possibility of abuse“The use of a steelyard in trade in the USSR was prohibited, as it is prohibited now in the territory of the Russian Federation.

The first simple device for measuring time, a sundial, was invented Babylonians approximately 3.5 thousand years ago.

But on the embankments of the city of Taganrog there is a real sundial, installed in 1833 on Grecheskaya Street at the beginning of the Stone Staircase.

They represent a dial applied to a marble slab (weight about 300 kg), which is mounted on a stone 8-sided stand strictly parallel to the horizon plane.

Sundial dial unusual: the numbers marked on it are calculated using a special formula; in addition to indicating the hours of the day, corrective amendments are given for each month.

The role of the time indicator is played by a metal triangle, one of the acute angles of which is equal to the geographical latitude of the city of Taganrog - 47°12"N.

The triangle is fixed perpendicular to the dial so that its hypotenuse is directed towards " celestial pole»

The hand of the Sundial is the edge of the shadow cast by the triangle on the dial.

Previously, Sundials showed true local solar time, and with the help of corrections given on the dial, it could be brought into line with mechanical watches.

Now this precision is lost. The sundial was made at a time when the concept of “ maternity leave» time. We now live according to Moscow time, but Taganrog is located southeast of Moscow, and solar noon occurs at 25 minutes. earlier than in the capital.

Now the clock is of interest as a unique monument.

Due to safety precautions, the use of mercury thermometers in educational institutions is prohibited, since mercury vapor is dangerous to human health

History of the thermometer

Celsius, Fahrenheit, Kelvin - who was first? One of the first inventors of the thermometer was the Italian scientist Galileo Galilei. In 1603, he invented a device not even remotely resembling a modern thermometer, and called it a thermoscope.

The device was a glass ball half filled with water and a glass tube leading out of it. The tube was divided into divisions, which conventionally indicated degrees, since the scale had not yet been invented. The operating principle of such a “device” was based on changes in temperature and atmospheric pressure.

Accordingly, the readings of such a thermometer were quite relative. And only in 1641 a thermoscope was put into production, in which colored alcohol was used as a thermometric liquid instead of water. It became possible to use such a device outdoors at sub-zero temperatures.

In this video, the balls are filled with alcohol and instead of a tube with divisions there are disks with a temperature value.

In 1724, the German scientist Gabriel Fahrenheit proposed using the Fahrenheit scale of the same name to measure temperature. Based on this scale, mercury thermometers were put into production. His scale is still used in a number of countries, the United States of America, Canada and Jamaica.

Over time, the devices improved and changed visually. In 1742, the Swedish scientist Andreas Celsius put his scale into use, but his young student Martin Stremmer slightly corrected his teacher’s invention by turning this scale over, which is what we are used to seeing on modern thermometers.

In 1860, the English scientist William Kelvin developed and proposed his own scale model. This scale is still successfully used by scientists today. It is very convenient for conducting experiments in various fields of science, thanks to its specific parameters.

So, in the course of working on physics on research project With regard to the physical instruments around us, we have once again become convinced of the need to be able to use a scale if we need to use a measuring device.

The same algorithm is used for scales of other measuring instruments. For example, for dynamometers.

Please note- the slide on the left shows laboratory dynamometers in the physics room, and on the right is a unique dynamometer, the division price of which is 0.001 N/div. There are no such dynamometers in any district school. And you see that with the help of this extraordinary dynamometer you can observe the interaction of the molecules of the soap solution.

Here is a demonstration dynamometer on the bottom hook of which 2 standard weights of 100g each are suspended, which means the effect is 2N; Another 1N also acts downward on the device from above. That dynamometer shows 3 N - the value of the resulting forces acting along one straight line and in one direction.

This experiment makes it possible to verify that if a force of 3N acts downwards, and 2N upwards, then the dynamometer on which these forces act will show 1N; if the forces are directed in opposite directions, then R = F1 - F2

That is, the resultant of forces directed along one straight line in opposite directions is directed towards the force with a larger magnitude, and its module is equal to the difference in the modules of the component forces.

So: I am sure that you are convinced of the need to know and be able to find the value of the scale division of any measuring instrument, in order to accurately take readings and no matter where - at school when doing laboratory work, or at home, because scale measuring instruments cannot be completely replaced by electronic ones.

a thermometer, a clock, a ruler, a beaker of various shapes and, of course, a wide variety of possibilities cell phones. The remaining devices are used by specialists in certain fields. So it turns out that if in the 20th century only specialists used measuring instruments, today the life of any person without instruments is practically impossible.

Conclusion

1) Theoretical significance lies in the fact that theoretical and practical knowledge and skills in determining the division value of a scale measuring device have been systematized; and the theory of determining the resultant force was experimentally confirmed.

2) Practical significance of this product is that this presentation can be used in physics lessons 7 when studying the algorithm for determining the price of division of an instrument scale and working with lever scales, determining the resultant forces, and in grade 9 the same topic as a repetition;

3) Dignity This project contains interesting historical and local history material in accordance with the stated topic.

Internet resources were used to write this work.

In school physics lessons, teachers always say that physical phenomena are everywhere in our lives. Only we often forget about this. Meanwhile, amazing things are nearby! Don't think that you need anything fancy to organize physical experiments at home. And here's some proof for you ;)

Magnetic pencil

What needs to be prepared?

• Battery.
• Thick pencil.
• Insulated copper wire with a diameter of 0.2–0.3 mm and a length of several meters (the longer, the better).
• Scotch.

Conducting the experiment

Wind the wire tightly, turn to turn, around the pencil, not reaching 1 cm from its edges. When one row ends, wind another on top in the opposite direction. And so on until all the wire runs out. Don’t forget to leave two ends of the wire, 8–10 cm each, free. To prevent the turns from unwinding after winding, secure them with tape. Strip the free ends of the wire and connect them to the battery contacts.

What happened?

It turned out to be a magnet! Try bringing small iron objects to it - a paper clip, a hairpin. They are attracted!

Lord of Water

What needs to be prepared?

• A plexiglass stick (for example, a student’s ruler or a regular plastic comb).
• A dry cloth made of silk or wool (for example, a wool sweater).

Conducting the experiment

Open the tap so that a thin stream of water flows. Rub the stick or comb vigorously on the prepared cloth. Quickly bring the stick closer to the stream of water without touching it.

What will happen?

The stream of water will bend in an arc, being attracted to the stick. Try the same thing with two sticks and see what happens.

Top

What needs to be prepared?

• Paper, needle and eraser.
• A stick and a dry woolen cloth from previous experience.

Conducting the experiment

You can control more than just water! Cut a strip of paper 1–2 cm wide and 10–15 cm long, bend it along the edges and in the middle, as shown in the picture. Insert the sharp end of the needle into the eraser. Balance the top workpiece on the needle. Prepare a “magic wand”, rub it on a dry cloth and bring it to one of the ends of the paper strip from the side or top without touching it.

What will happen?

The strip will swing up and down like a swing, or spin like a carousel. And if you can cut a butterfly out of thin paper, the experience will be even more interesting.

Ice and fire

(the experiment is carried out on a sunny day)

What needs to be prepared?

• A small cup with a round bottom.
• A piece of dry paper.

Conducting the experiment

Pour water into a cup and place it in the freezer. When the water turns to ice, remove the cup and place it in a container of hot water. After some time, the ice will separate from the cup. Now go out onto the balcony, place a piece of paper on the stone floor of the balcony. Use a piece of ice to focus the sun on a piece of paper.

What will happen?

The paper should be charred, because it’s not just ice in your hands anymore... Did you guess that you made a magnifying glass?

Wrong mirror

What needs to be prepared?

• A transparent jar with a tight-fitting lid.
• Mirror.

Conducting the experiment

Fill the jar with excess water and close the lid to prevent air bubbles from getting inside. Place the jar with the lid facing up against the mirror. Now you can look in the “mirror”.

Bring your face closer and look inside. There will be a thumbnail image. Now start tilting the jar to the side without lifting it from the mirror.

What will happen?

The reflection of your head in the jar, of course, will also tilt until it turns upside down, and your legs will still not be visible. Lift the can and the reflection will turn over again.

Cocktail with bubbles

What needs to be prepared?

• A glass with a strong solution of table salt.
• A battery from a flashlight.
• Two pieces of copper wire approximately 10 cm long.
• Fine sandpaper.

Conducting the experiment

Clean the ends of the wire with fine sandpaper. Connect one end of the wire to each pole of the battery. Dip the free ends of the wires into a glass with the solution.

What happened?

Bubbles will rise near the lowered ends of the wire.

Lemon battery

What needs to be prepared?

• Lemon, thoroughly washed and wiped dry.
• Two pieces of insulated copper wire approximately 0.2–0.5 mm thick and 10 cm long.
• Steel paper clip.
• A light bulb from a flashlight.

Conducting the experiment

Strip the opposite ends of both wires at a distance of 2–3 cm. Insert a paper clip into the lemon and screw the end of one of the wires to it. Insert the end of the second wire into the lemon, 1–1.5 cm from the paperclip. To do this, first pierce the lemon in this place with a needle. Take the two free ends of the wires and apply them to the contacts of the light bulb.

What will happen?

The light will light up!

Artificial tornado. One of N. E. Zhukovsky’s books describes the following installation for producing an artificial tornado. At a distance of 3 m above the vat of water, a hollow pulley with a diameter of 1 m is placed, which has several radial partitions (Fig. 119). When the pulley rotates quickly, a spinning waterspout rises from the vat to meet it. Explain the phenomenon. What is the reason for the formation of a tornado in nature?

“Universal barometer” by M. V. Lomonosov (Fig. 87). The device consists of a barometric tube filled with mercury, having a ball A at the top. The tube is connected by a capillary B to another ball containing dry air. The device is used to measure minute changes in atmospheric pressure. Understand how this device works.

Device N. A. Lyubimov. Moscow University professor N.A. Lyubimov was the first scientist to experimentally study the phenomenon of weightlessness. One of his devices (Fig. 66) was a panel l with loops, which could fall along the guide vertical wires. On the panel l a vessel with water is strengthened 2. A large plug 3 is placed inside the vessel with the help of a rod passing through the lid of the vessel. Water tends to push out the plug, and the latter, stretching the rod. 4, hold the pointer arrow on the right side of the screen. Will the needle maintain its position relative to the vessel if the device falls?

“The use of homemade devices is one of the ways to activate students’ cognitive activity when studying physics”

Yesenzhulova A.D.

2016

Do you know how strong one person can be?

Fyodor Dostoevsky

Annotation

This project is intended for physics teachers and students in grades 7-11. It makes it possible to get away from “chalk” physics and is aimed at involving schoolchildren in the manufacture of instruments and at identifying the creative abilities of children.

Relevance is that the manufacture of instruments leads not only to an increase in the level of knowledge, but also reveals the main direction of students’ activities. When working on the device, we move away from “chalk” physics. A dry formula comes to life, an idea materializes, and a complete and clear understanding arises. On the other hand, such work is a good example of socially useful work: successfully made homemade devices can significantly supplement the equipment of a school office. Homemade devices also have another permanent value: their production, on the one hand, develops practical skills in the teacher and students, and on the other hand, testifies to creative work and the methodological growth of the teacher.

The way out of a difficult situation most often happens where there was an entrance...

Karel Capek

Problematic issues

• Is it worth it to manufacture homemade physics instruments when industry produces them in sufficient quantities and of high quality?
• How to replenish a physics classroom with equipment without material costs?
• What homemade devices need to be made?

Make devices and physics installations to demonstrate physical phenomena, explain the operating principle of each device and demonstrate their operation.

Hypothesis

The presence of homemade instruments in a school physics classroom expands the possibilities for improving educational experiments and improves the organization of scientific research work.

1) study scientific and popular literature on creating homemade devices;

2) make instruments on specific topics that cause difficulty in understanding theoretical material in physics;

3) make devices that are not available in the laboratory;

Diagnostic results

What do you like about studying physics? ?

a) problem solving -19%;

b) demonstration of experiments - 21%;

c) reading a textbook at home - 4%;

d) teacher telling new material - 17%;

d) independent performance of experiments -36%;

e) the answer at the board is -3%.

What homework do you prefer to do?

a) reading a textbook -22%;

b) solving problems from the textbook -20%;

V) observation of physical phenomena -40%;

d) drawing up tasks -7%;

e) production of simple devices, models -8%;

f) solving difficult problems – 3%.

Which lesson are you interested in?

a) on the test - 3%;

b) in laboratory work - 60%;

c) in a problem solving lesson - 8%;

d) in a lesson of learning new material - 22%;

e) don’t know -7%.

Homemade device

With your own hands

Homemade device

Crusher

Homemade device

Sewing machine

Pupil 9 Tishchenko A

Homemade device

Zhangabaev A 10 D class

Nuranov A 10 G class

1. Self-made physical installations have greater didactic impact.

2. Homemade installations are created for specific conditions.

3. Homemade installations are a priori more reliable.

4. Homemade units are much cheaper than government-issued units.

5. Self-made installations often determine the fate of a student.

I value one experience more than a thousand opinions,

born only from imagination

M. Lomonosov

Conclusion

It will be great if our project “charges” with creative optimism and makes someone believe in themselves. After all, this is his main goal: to present the complex as accessible, worth any effort and capable of giving a person the incomparable joy of comprehension and discovery. Perhaps our project will encourage someone to be creative. After all, creative vigor is like a strong elastic spring that harbors the charge of a powerful blow. No wonder the wise aphorism says: “Only a beginning creator is omnipotent!”

Offer:

The condition and work of school physics classrooms should be assessed not by the dubious millions of rubles spent on dubious pseudo-equipment, but by the number of home-made installations, their coverage of the school physics course and school students.

Masters...Professionals

Those that were able to comprehend in life

Generosity of stone, soul of metal

Freshness of the formula, character of the earth

Masters. Mastaki. Craftsmen

Understanding to the depths

Machine and heart mechanism

The stroke of the bow or the hum of turbines

Extending prophetic hands

To the crossroads of star worlds

Time moves by masters and relies on masters!

... And they stand like fortresses,

In the rightness of your work

And they can't do otherwise

And required

Robert Rozhdestvensky

Literature

1. N.M. Shakhmaev Physical experiment in high school.

2. L.I.Antsiferov. Homemade devices for physics workshop.

3. N.M. Markosova. Studying ultrasound in a physics course.

4. N.M. Zvereva. Activating students' thinking in physics lessons.

5. S. Pavlovich. Devices and models for inanimate nature.

6. I.Ya.Lanina. Not just a lesson.

7. S.A. Khoroshavin. Physical and technical modeling.

8. L.I. Antsiferov “Homemade devices for Physics workshop” Moscow Enlightenment 1985

9. A.I. Ukhanov “Homemade devices in physics” Saratov SSU 1978

Municipal educational institution "Secondary school No. 2" Babynino village

Babyninsky district, Kaluga region

X research conference

“Gifted children are the future of Russia”

Project "Physics with your own hands"

Prepared by the students

7 "B" class Larkova Victoria

7 "B" class Kalinicheva Maria

Head Kochanova E.V.

Babynino village, 2018

Introduction page 3

Theoretical part p.5

Experimental part

Fountain model p.6

Communicating vessels page 9

Conclusion page 11

References page 13

Introduction

This academic year we plunged into the world of a very complex but interesting science that is necessary for every person. From the first lessons we were fascinated by physics; we wanted to learn more and more new things. Physics is not only physical quantities, formulas, laws, but also experiments. Physical experiments can be done with anything: pencils, glasses, coins, plastic bottles.

Physics is an experimental science, so creating instruments with your own hands contributes to a better understanding of laws and phenomena. Many different questions arise when studying each topic. The teacher, of course, can answer them, but how interesting and exciting it is to get the answers yourself, especially using hand-made instruments.

Relevance: Making instruments not only helps to increase the level of knowledge, but is one of the ways to enhance the cognitive and project activities of students when studying physics in primary school. On the other hand, such work serves as a good example of socially useful work: successfully made homemade devices can significantly replenish the equipment of a school office. It is possible and necessary to make devices on site on your own. Homemade devices also have another value: their production, on the one hand, develops practical skills and abilities in teachers and students, and on the other, indicates creative work.Target: Make a device, a physics installation to demonstrate physical experiments with your own hands, explain its principle of operation, demonstrate the operation of the device.
Tasks:

1. Study scientific and popular literature.

2. Learn to apply scientific knowledge to explain physical phenomena.

3. Make devices at home and demonstrate their operation.

4. Replenishing the physics classroom with homemade instruments made from scrap materials.

Hypothesis: Use the made device, a physics installation for demonstrating physical phenomena with your own hands in the lesson.

Project product: DIY devices, demonstration of experiments.

Project result: interest of students, the formation of their idea that physics as a science is not divorced from real life, development of motivation for learning physics.

Research methods: analysis, observation, experiment.

The work was carried out according to the following scheme:

Studying information from various sources on this issue.

Selection of research methods and practical mastery of them.

Collecting your own material – assembling available materials, conducting experiments.

Analysis and formulation of conclusions.

I . Main part

Physics is the science of nature. She studies phenomena that occur in space, in the bowels of the earth, on the earth, and in the atmosphere - in a word, everywhere. Such phenomena are called physical phenomena. When observing an unfamiliar phenomenon, physicists try to understand how and why it occurs. If, for example, a phenomenon occurs quickly or occurs rarely in nature, physicists strive to see it as many times as necessary in order to identify the conditions under which it occurs and establish the corresponding patterns. If possible, scientists reproduce the phenomenon being studied in a specially equipped room - a laboratory. They try not only to examine the phenomenon, but also to make measurements. Scientists – physicists – call all this experience or experiment.

We were inspired by the idea of ​​making our own devices. Carrying out our scientific fun at home, we developed basic actions that allow you to successfully conduct the experiment:

Home experiments must meet the following requirements:

Safety during carrying out;

Minimum material costs;

Ease of implementation;

Value in learning and understanding physics.

We conducted several experiments on various topics in the 7th grade physics course. Let's present some of them, interesting and at the same time easy to implement.

Experimental part.

Fountain model

Target: Show the simplest model of a fountain

Equipment:

Large plastic bottle - 5 liters, small plastic bottle - 0.6 liters, cocktail straw, piece of plastic.

Progress of the experiment

We bend the tube at the base with the letter G.

Secure it with a small piece of plastic.

Cut a small hole in a three-liter bottle.

Cut off the bottom of a small bottle.

Secure the small bottle into the large one using a cap, as shown in the photo.

Insert the tube into the cap of a small bottle. Secure with plasticine.

Cut a hole in the cap of a large bottle.

Let's pour water into a bottle.

Let's watch the flow of water.

Result : we observe the formation of a water fountain.

Conclusion: The water in the tube is affected by the pressure of the liquid column in the bottle. The more water in the bottle, the larger the fountain will be, since the pressure depends on the height of the liquid column.

Communicating vessels

Equipment: upper parts from plastic bottles of different sections, rubber tube.

Let's cut off the top parts of plastic bottles, 15-20cm high.

We connect the parts together with a rubber tube.

Progress of experiment No. 1

Target : show the location of the surface of a homogeneous liquid in communicating vessels.

1.Pour water into one of the resulting vessels.

2. We see that the water in the vessels is at the same level.

Conclusion: in communicating vessels of any shape, the surfaces of a homogeneous liquid are set at the same level (provided that the air pressure above the liquid is the same).

Progress of experiment No. 2

1. Let’s observe the behavior of the surface of water in vessels filled with different liquids. Pour equal amounts of water and detergent into connected containers.

2. We see that the liquids in the vessels are at different levels.

Conclusion : in communicating vessels, heterogeneous liquids are established at different levels.

Conclusion

It is interesting to observe the experiment conducted by the teacher. Carrying it out yourself is doubly interesting. The experiment carried out with a hand-made device arouses great interest among the whole class. Such experiments help to better understand the material, establish connections and draw the right conclusions.

We conducted a survey among seventh grade students and found out whether physics lessons with experiments are more interesting, and whether our classmates would like to make a device with their own hands. The results turned out like this:

Most students believe that physics lessons become more interesting with experiments.

More than half of the surveyed classmates would like to make instruments for physics lessons.

We enjoyed making homemade instruments and conducting experiments. There are so many interesting things in the world of physics, so in the future we will:

Continue studying this interesting science;

Conduct new experiments.

References

1. L. Galpershtein “Funny Physics”, Moscow, “Children’s Literature”, 1993.

Teaching equipment for physics in high school. Edited by A.A. Pokrovsky “Enlightenment”, 2014

2. Textbook on physics by A. V. Peryshkina, E. M. Gutnik “Physics” for grade 7; 2016

3. Ya.I. Perelman “Entertaining tasks and experiments”, Moscow, “Children’s Literature”, 2015.

4. Physics: Reference materials: O.F. Kabardin Textbook for students. – 3rd ed. – M.: Education, 2014.

5.//class-fizika.spb.ru/index.php/opit/659-op-davsif

a- Roma Davydov Head: physics teacher - Khovrich Lyubov Vladimirovna Novouspenka – 2008

Goal: Make a device, a physics installation to demonstrate physical phenomena with your own hands. Explain the operating principle of this device. Demonstrate the operation of this device.

HYPOTHESIS: Use the made device, installation in physics to demonstrate physical phenomena with your own hands in the lesson. If this device is not available in the physical laboratory, this device will be able to replace the missing installation when demonstrating and explaining the topic.

Objectives: Make devices that arouse great interest among students. Make devices that are not available in the laboratory. make devices that cause difficulty in understanding theoretical material in physics.

EXPERIMENT 1: Forced oscillations. With uniform rotation of the handle, we see that the action of a periodically changed force will be transmitted to the load through the spring. Changing with a frequency equal to the frequency of rotation of the handle, this force will force the load to perform forced vibrations. Resonance is the phenomenon of a sharp increase in the amplitude of forced vibrations.

Forced vibrations

EXPERIENCE 2: Jet propulsion. We will install a funnel in a ring on a tripod and attach a tube with a tip to it. We pour water into the funnel, and when the water begins to flow out from the end, the tube will bend in the opposite direction. This is reactive movement. Reactive motion is the movement of a body that occurs when some part of it is separated from it at any speed.

Jet propulsion

EXPERIMENT 3: Sound waves. Let's clamp a metal ruler in a vice. But it is worth noting that if most of the ruler acts as a vice, then, having caused it to oscillate, we will not hear the waves generated by it. But if we shorten the protruding part of the ruler and thereby increase the frequency of its oscillations, then we will hear the generated Elastic waves, propagating in the air, as well as inside liquid and solid bodies, but are not visible. However, when certain conditions they can be heard.

Sound waves.

Experiment 4: Coin in a bottle Coin in a bottle. Want to see the law of inertia in action? Prepare a half-liter milk bottle, a cardboard ring 25 mm wide and 0 100 mm wide and a two-kopeck coin. Place the ring on the neck of the bottle, and place a coin on top exactly opposite the hole in the neck of the bottle (Fig. 8). After inserting a ruler into the ring, hit the ring with it. If you do this abruptly, the ring will fly off and the coin will fall into the bottle. The ring moved so quickly that its movement did not have time to be transferred to the coin, and according to the law of inertia, it remained in place. And having lost its support, the coin fell down. If the ring is moved to the side more slowly, the coin will “feel” this movement. The trajectory of its fall will change, and it will not fall into the neck of the bottle.

Coin in a bottle

Experiment 5: Floating Ball When you blow, a stream of air lifts the ball above the tube. But the air pressure inside the jet is less than the pressure of the “quiet” air surrounding the jet. Therefore, the ball is located in a kind of air funnel, the walls of which are formed by the surrounding air. By smoothly reducing the speed of the jet from the upper hole, it is not difficult to “plant” the ball in its original place. For this experiment you will need an L-shaped tube, for example glass, and a light foam ball. Close the top hole of the tube with a ball (Fig. 9) and blow into the side hole. Contrary to expectation, the ball will not fly away from the tube, but will begin to hover above it. Why is this happening?

floating ball

Experiment 6: Movement of a body along a “dead loop” Using the “dead loop” device, you can demonstrate a number of experiments on the dynamics of a material point along a circle. The demonstration is carried out in the following order: 1. The ball is rolled down the rails from the highest point of the inclined rails, where it is held by an electromagnet, which is powered by 24V. The ball steadily describes a loop and flies out at a certain speed from the other end of the device2. The ball is rolled down from the lowest height when the ball just describes the loop without falling off its top point3. From an even lower height, when the ball, not reaching the top of the loop, breaks away from it and falls, describing a parabola in the air inside the loop.

Body movement in a "dead loop"

Experiment 7: Hot air and cold air Stretch a balloon onto the neck of an ordinary half-liter bottle (Fig. 10). Place the bottle in a pan of hot water. The air inside the bottle will begin to heat up. The molecules of the gases that make up it will move faster and faster as the temperature rises. They will bombard the walls of the bottle and ball more strongly. The air pressure inside the bottle will begin to increase and the balloon will begin to inflate. After a while, transfer the bottle to a pan of cold water. The air in the bottle will begin to cool, the movement of molecules will slow down, and the pressure will drop. The ball will wrinkle as if the air has been pumped out of it. This is how you can verify the dependence of air pressure on the ambient temperature

The air is hot and the air is cold

Experiment 8: Stretching a solid body Taking the foam block by the ends, stretch it. The increase in distances between molecules is clearly visible. It is also possible to simulate the occurrence of inter-molecular attractive forces in this case.

Tension of a rigid body

Experiment 9: Compression of a solid body Compress a foam block along its major axis. To do this, place it on a stand, cover the top with a ruler and apply pressure with your hand. A decrease in the distance between the molecules and the emergence of repulsive forces between them are observed.

Compression of a solid

Experiment 4: Double cone rolling upward. This experiment serves to demonstrate experience confirming that a freely moving object is always positioned in such a way that the center of gravity occupies the lowest possible position for it. Before demonstration, the planks are placed at a certain angle. To do this, the double cone is placed with its ends into the cutouts made in the upper edge of the planks. Then the cone is moved down to the beginning of the planks and released. The cone will move upward until its ends fall into the cutouts. In fact, the center of gravity of the cone, lying on its axis, will shift downward, which is what we see.

Are grasshoppers pests or beneficial insects?

The grasshopper is an arthropod insect, belongs to the superorder New-winged insects, the order Orthoptera, the suborder Long-whiskered Orthoptera, the superfamily grasshoppers (Tettigonioidea). The Russian word “grasshopper” is considered a diminutive of the word “smith”. But to the body

Elective course

Annotation

The elective course is intended for students who want to gain experience in independently applying knowledge in physics in practice when conducting experiments, i.e. subject-specific character. The course provides information about methods of physical measurements that are useful not only to future physicists or engineers, but also to every person in his everyday practical life. In laboratory classes, schoolchildren will learn to confidently and safely use a variety of physical instruments, from a ruler and micrometer to a digital multimeter, and will acquire practical skills to competently use a thermometer in everyday practice, measure air humidity, blood pressure, and check the serviceability of household electrical appliances. Experience of practical work with physical instruments will help the student in making an informed choice of a profile for further education.

The course is built on the knowledge and skills of students acquired while studying physics, it provides an opportunity to become more deeply acquainted with the methods of measuring physical quantities, acquire skills in the practical use of measuring instruments, processing and analysis of the results obtained.

Explanatory note

The purpose of the course is to provide students with the opportunity to satisfy their individual interest in studying practical applications of physics in the process of cognitive and creative activity while conducting independent experiments and research.

Basic course objective is to help the student make an informed choice of a profile for further education. In elective classes, the student will become familiar with the types of activities that are leading in many engineering and technical professions related to the practical applications of physics. The experience of independently performing first simple physical experiments, then research and design tasks will allow the student to either verify the correctness of his preliminary choice, or change his choice and test his abilities in some other direction.

In theoretical classes of the first level ( "Learning to measure!") Methods for measuring physical quantities, the design and operating principle of measuring instruments, methods for processing and presenting measurement results are considered. In practical classes when performing laboratory work, students will be able to acquire the skills and abilities to plan a physical experiment in accordance with the task, learn to choose a rational measurement method, perform an experiment and process its results.

Completing practical and experimental tasks of the second level ( “We measure ourselves!”) will allow students to apply acquired skills in a non-standard environment and become competent in many practical issues. Seminar classes contribute to the development of the ability to independently acquire knowledge, critically evaluate the information received, express one’s point of view on the issue under discussion, listen to other opinions and discuss them constructively.

Third level ( “We explore, invent, design, model!”)– improving practical skills and developing creative approaches to business . At this level, students will have to complete laboratory work in a physics workshop devoted to the study of certain processes and phenomena in physics, test their strength in performing individual experimental tasks and design work, working as independently as they wish and are able. At the end of this stage, students can present the results of their research, for example, at a class or school creative work competition.

Thus, the main activities of students in the elective course are independent work in the physics laboratory and performing simple experimental tasks of interest at home.

All types of practical tasks are designed to use standard equipment in a physics classroom and can be performed by all students in the group in the form of laboratory work or as individual experimental tasks for students of their choice.

Elective classes will be useful for students in solving problems encountered in people's everyday lives, such as correctly measuring temperature, measuring blood pressure, and checking the serviceability of electrical appliances. Students should ensure that they can become competent in many practical matters now. The proposed problems are simple, but solving them requires creative application of knowledge. Based on familiarization with the structure and operating principles of physical measuring instruments, and the acquisition of independent experience in their use, schoolchildren develop a sense of confidence in their abilities to successfully interact with objects of the surrounding world and various technical devices.

The elective course is aimed at developing a sense of confidence in one’s strengths and abilities when using a variety of devices and household appliances in everyday life, as well as developing interest in carefully examining familiar phenomena and objects. The desire to understand, to understand the essence of phenomena, the structure of things that serve a person all his life, will inevitably require additional knowledge, will push him to self-education, a person will observe, think, read, improve and invent - he will be interested in living!

Main course content

Methods for measuring physical quantities (h)

First level: learning to measure!

Basic and derived physical quantities and their measurements. Units and standards of quantities. Absolute and relative errors of direct measurements. Measuring instruments, tools, measures. Instrumental and reading errors. Instrument classes. Limits of systematic errors and methods for their assessment. Random measurement errors and estimation of their limits.

Stages of planning and performing an experiment. Precautions when conducting the experiment. Taking into account the influence of measuring instruments on the process under study. Selection of measurement method and measuring instruments. Methods for monitoring measurement results. Recording measurement results. Tables and graphs. Processing of measurement results. Discussion and presentation of the results obtained.

Dimensions of time. Methods for measuring thermal quantities. Methods for measuring electrical quantities. Methods for measuring magnetic quantities. Methods for measuring light quantities. Methods of measurement in atomic and nuclear physics.

Laboratory work

1. Measuring length using a scale ruler and micrometer.

2. Estimation of error limits when measuring current strength.

3. Electrical resistance measurements using an ohmmeter.

4. Measuring the friction coefficient.

5. Study of the dependence of current on voltage at the ends of the filament of an electric lamp.

6. Study of the dependence of the period of oscillation of a pendulum on its mass, amplitude of oscillations and length.

7. Measuring a person’s reaction time to a light signal.

Physical measurements in everyday life (h)

Second level: Let's move on to independent measurements!

Temperature measurements at home. Air humidity and methods of measuring it. Heart function studies. Sources of electrical voltage are all around us. Household electrical appliances. Household.

Laboratory work

8. Study of the dependence of thermometer readings on external conditions.

9. Air humidity measurement.

10. Measurement of arterial blood pressure.

11. Studying the principle of operation of an electric lighter.

12. Studying the principle of operation of a fluorescent lamp.

Physics workshop (h)

Third level: We explore, we invent, we construct, we model!

Laboratory work

13. Measuring the kinetic energy of a body.

14. Study of the properties of laser radiation.

Experimental tasks

ü Making a model of a gas thermometer.

ü Making a model of a fire alarm machine.

ü Calculation and testing of a model of an automatic device for temperature control.

Time reserve - 1h.

Organization and conduct of student certification

Elective classes in this program are conducted to satisfy the individual interest of students in studying practical applications of physics and to help in choosing a profile for further study. Therefore, there is no need to systematically monitor and evaluate students' knowledge. However, their achievements should be celebrated and thereby encouraged to continue their studies.

The credit form for assessing student achievements is most consistent with the characteristics of elective classes. It is advisable to give credit for laboratory work performed on the basis of a written report, which briefly describes the experimental conditions, presents the measurement results in a systematic way, and draws conclusions.

Based on the results of completing creative experimental tasks, in addition to written reports, it is useful to practice reports in a general group lesson with a demonstration of the experiments performed and the devices manufactured. To sum up the overall results of the entire group’s activities, it is possible to hold a competition of creative works. At this competition, students will not only be able to demonstrate the experimental installation in action, but also talk about its originality and capabilities, and present their creation to the audience. Here, the ability to format your report with graphs, tables, and briefly and emotionally talk about the most important things becomes of great importance. At school-wide competitions, for example, works by biologists, chemists, and writers can be presented. In this case, it becomes possible to see and evaluate your work and yourself against the background of other interesting works and equally passionate people.

The student’s final grade for the entire elective course can be assigned, for example, according to the following criteria:

1) completion of at least half of the laboratory work;

2) completing at least one experimental task of a research or design type;

3) active participation in the preparation and conduct of seminars, discussions, competitions. The proposed criteria for assessing student achievements can only serve as a guide, but are not mandatory.

Based on his experience, the teacher can set other criteria.

Methods for measuring physical quantities

§ 1. Physical quantities and their units.

Physics; physical properties of bodies; history of the meter; modern definition of meter; physical quantity; basic and derived physical quantities; units of quantities and standards; international system of units SI.

§ 2. Measurements of physical quantities.

Measurements of physical quantities; size and value of a physical quantity; measures and measuring instruments; direct and indirect measurements; absolute and relative measurement errors; length measurements.

Laboratory work 1. Measuring length using a scale ruler and micrometer.

§3. Errors of direct single measurements.

Measurement error limits; limits of absolute and relative error; instrumental error; instrument accuracy class; reading error; measurement method error; systematic and random errors; how measurement errors can be taken into account or reduced.

Laboratory work 2. Estimation of error limits in current measurements.

§4. Safety of the experiment.

Ensuring the safety of the experiment for humans; precautions; ensuring the safety of the experiment for measuring instruments and equipment.

§5. Planning and execution of the experiment.

Selection of measurement method and instruments; influence of instruments on measurement results; preliminary measurements; selection of the stage of change of the controlled variable; maintaining constant experimental conditions.

§6. Estimation of the limits of random measurement errors.

Repeated measurements and finding the arithmetic mean of the measured value; standard deviation; standard deviation; assessment of the limits of random measurement errors.

Laboratory work 5. Friction coefficient measurement.

§7. Processing of measurement results.

Approximate numbers; assessment of the error limits of indirect measurements; recording and processing measurement results: six simple rules.

§8. Building graphs.

Presentation of measurement results in the form of tables; assignment of schedules; constructing an approximate graph; scale selection; indication of error limits on the graph; drawing lines along experimental points; analysis of results.

Laboratory work 7. Study of the dependence of current on voltage at the ends of an electric lamp filament.

§9. Measuring time.

What is time; day is a natural unit of time; simple instruments for measuring time; pendulum clocks; uneven rotation of the Earth; electronic and atomic time standards.

Laboratory work 8. Study of the dependence of the period of oscillation of a pendulum on its mass, amplitude of oscillations and length.

Laboratory work 9. Measuring a person's reaction time to a light signal.

§10. Methods for measuring thermal quantities.

Temperature; heat exchange; liquid thermometer; gas thermometer.

§11. Methods for measuring electrical quantities.

Instruments for measuring current strength; voltage measuring instruments; symbols; electronic digital measuring instruments.

§12. Methods for measuring magnetic quantities.

Magnetic induction; magnetic flux; inductance.

§13. Methods for measuring light quantities.

Light sources; light quantities and their units.

§14. Methods of measurements in atomic and nuclear physics.

Physical quantities in atomic and nuclear physics; absorbed radiation dose; methods for recording charged particles.

§15. How should you measure temperature?

Thermometer; temperature measurement.

Laboratory work 15. Study of the dependence of thermometer readings on external conditions.

§16. Humidity measurement. Humidity; hygrometer.

Laboratory work 16. Air humidity measurement.

§17. Study of heart function.

Human circulatory system; blood pressure; sphygmomanometer; when and why you need to measure blood pressure.

Lab 1 7. Measurement of arterial blood pressure.

§18. Electric currents of the heart.

Galvanic phenomena; electrocardiogram.

§19. Sources of electrical voltage around us

Sources of electrical voltage in the house; checking the serviceability of an electrical appliance; gas discharge indicator; How does an electric lighter work?

Laboratory work 18. Studying the operating principle of a piezoelectric lighter.

§20. Household light sources. Incandescent lamp; fluorescent lamp.

Laboratory work 19. Studying the principle of operation of a fluorescent lamp.

Chapter 3. Physics workshop

Laboratory work 20. Measuring the kinetic energy of a body.

Laboratory work 25. Study of the properties of laser radiation.

Experimental task 1. Making a model of a gas thermometer.

Experimental task 5. Making a model of an alarm system.

Experimental task 6. Calculation and testing of a model of an automatic device for temperature control.

FRAGMENT OF TUTORIAL

Measurements of physical quantities. By measuring physical quantity is called experimental determination values physical quantity characterizing a given object. The value of a physical quantity is the product of an abstract number, called the numerical value of the quantity, by unit physical quantity. For example, the value of table length / = 1.5 m = 1.5 x1 m. In this case, the numerical value 1.5 shows how many units of length 1 m fit on the length of the table.

The quantitative content of a characteristic of a physical object or phenomenon is called size physical quantity. Quantity size for a given object remains unchanged when choosing different units of measurement, the value of the quantity depends on the choice of unit measurements. For example, a body measuring 1 foot has different lengths when using different units of length:

/ = 1 foot = 12 inches = 30.48 cm = 0.3048 m.

The basis of all measurements of physical quantities is the comparison of the size of the measured quantity with a standard physical unit quantities. For example, to measure the length of an object, you need to compare its length with the length of a standard meter.

Measures and measuring instruments. It is impossible to perform all measurements by comparisons with a single standard unit of magnitude. For measurements in research laboratories and in everyday practical life, measures And measuring instruments, compared with standards.

An unambiguous measure is a means of measurement that reproduces a physical quantity of a certain size. For example, a kilogram weight is a measure of mass measuring 1 kg. A 1 H sample coil can serve as a measure of 1 H inductance.

Measuring ruler with millimeter divisions on a scale or a set of weights different meanings can serve as examples multi-valued measures

A measuring instrument is a measuring instrument that makes it possible to directly read the values ​​of the measured quantity. The measuring device is used to generate a signal that directly shows the value of the physical quantity being measured. Examples of measuring instruments include a dynamometer, speedometer, voltmeter, ammeter, thermometer, and pressure gauge.

Measurements in which the measuring device provides direct information about the value of the physical quantity being measured are called direct measurements.

Measurements in which the value of the measured quantity is found by calculations based on the use of measurement results of other quantities are called indirect measurements.

Measurement errors. When measuring physical quantities with any instruments, the measurement result always differs somewhat from the true value of the physical quantity. These differences may be due to the imperfection of the measuring device, experimenter error, the influence of external factors and other reasons.

The magnitude of the difference between the measurement result and the true value of the measured value is called the absolute measurement error.

If when measuring a segment AB length A the measurement result is obtained, then the absolute measurement error 8x is determined by the expression:

8x = δ X - 4 (1) where δ is the lowercase letter "delta" of the Greek alphabet.

Absolute error does not give a complete picture of the quality of the measurement. For example, if we only know that the distance was measured with an absolute error of 3 cm, then it cannot be said good quality this is a measurement or bad. Indeed, if the distance from Moscow to St. Petersburg is measured with such an error, equal to approximately 600 km, then we can say that this measurement is of very high quality. And if you made an error of 3 cm when cutting glass about 60 cm wide for insertion into a window frame, then you will most likely need new glass, so the quality of the measurements in this case cannot be considered good. Consequently, the quality of measurements is determined not only by the absolute measurement error, but also by the value of the measured quantity. The characteristic of measurement quality, taking into account the absolute error and the value of the measured quantity, is called relative measurement error.

Relative measurement error is the ratio of the absolute error to the true value of the measured quantity. The relative error is expressed in fractions of a unit or as a percentage.

As calculations show, the relative error clearly demonstrates a significant difference in the quality of the first and second measurements with the same absolute measurement error. Therefore, in most cases, the quality of measurements is assessed by the value of its relative error.

Length measurements. To measure the linear dimensions of bodies and the distances between bodies, various measuring instruments and measurement methods are used. To measure large lengths, for example land plots, steel measuring tapes up to 50 m long are used. When measuring buildings, a tape measure with a flexible tape 10-20 m long, divided into centimeters, is used. Scale rulers are used to measure small objects. To measure the size of small objects with an accuracy of tenths of a millimeter, a caliper or micrometer is used. The main part of the micrometer is a steel bracket 1. A fixed heel 2 is fixed in it on one side, and a stem 4 on the other. A micrometer screw 3 is placed inside the stem, ending on the left side with a measuring surface. WITH right side the micrometer screw is connected to a drum 5 enclosing the micrometer stem. When the drum rotates, the micrometer screw also rotates. The screw pitch is 0.5 mm, so the measuring surface of the screw with one revolution of the drum moves 0.5 mm relative to the stationary heel of the micrometer.

A longitudinal mark is applied to the surface of the stem, below which there is a scale with millimeter strokes, and above there is a scale with strokes dividing each millimeter division of the upper scale in half. 50 equally spaced strokes are applied along the left edge of the drum, allowing the rotation of the micrometer screw to be determined with an accuracy of 1/50 of a revolution. Since with one revolution the measuring surface of the micrometer screw shifts by 0.5 mm, when turned by 1/50th of a revolution its displacement is equal to 0.01 mm.

When the measuring surface of the micrometer screw is closed with the surface of the fixed heel, the edge of the drum is set against the zero mark on the stem scale. To measure the size of a part, it is placed between the heel and the measuring surface of a micrometer screw. Then, by rotating the drum, the measuring surfaces of the heel and the micrometer screw come into contact with the surface points of the part being measured. To prevent deformation of the part being measured, the force of pressing the micrometer screw on the part being measured is limited using a ratchet 6. To do this, the micrometer screw is rotated using a ratchet and the rotation stops when a sound appears. The micrometer makes it possible to determine the size of a part with an accuracy of 0.5 mm on the scale on the stem and with an accuracy of 0.01 mm on the scale on the micrometer drum against the longitudinal mark on the stem.

Security questions

What is the measurement of a physical quantity? What is the size and meaning of a physical quantity? What measurements are called direct measurements? What measurements are called indirect measurements? What is absolute measurement error? What is the relative measurement error?

Lab 1

Measuring length using a scale ruler and micrometer.

Purpose of the work. Acquiring skills to evaluate absolute and relative measurement errors.

Equipment: scale ruler, micrometer, coin.

Exercise: measure the diameter of the coin using a scale ruler and determine the absolute and relative measurement errors.

1. Measure the diameter D1 of the coin using a scale ruler and record the measurement result in the reporting table.

2. Get to know the structure and operating principle of a micrometer. Measure the diameter D0 coins using a micrometer and record the measurement results in the report table.

3. Conventionally taking the value of D0 as exact value coin diameter, calculate the absolute and relative measurement errors using a scale ruler. Record the results in the reporting table.

Report table

D , mm	D0, mm	d,-do\

Security questions

What reasons can cause measurement errors?

In what ways can measurement errors be reduced?

Task

Imagine that you live approximately in the 3rd-2nd centuries BC and have only such devices and tools as scientists had at that time. Under these conditions, try to come up with a method for measuring the distances to the Moon and the stars. If you find a fundamental solution to the problem, test your method on a model. Let a small ball or rubber ball be a model of the Moon. Place the “Moon” at a distance of 5-6 meters from you and try to measure the distance to the “Moon” and its diameter. Then use direct measurements to check how good your method is.

FRAGMENT OF THE METHODOLOGICAL MANUAL

§ 2. Measurements of physical quantities

In order to begin measuring physical quantities, students need to be introduced to such concepts as the size and value of a physical quantity, explain what a measure is and what is called a measuring device, which measurements are called direct and which are indirect, what is absolute and relative measurement errors. However, theoretical acquaintance should be very brief and directly related to the implementation of laboratory work and creative tasks.

Laboratory work 1.

Length measurements are the simplest and most common measurements that are constantly encountered in everyday life. The simple task of measuring the diameter of a coin using a scale ruler and then a micrometer can be introduced to students in order to practice the acquired knowledge about absolute and relative measurement errors and prepare for the introduction of the concepts of instrumental and reference error in the next lesson. The second task of laboratory work is to become familiar with a precision measuring instrument - a micrometer.

Task. In a strong group of students, Lab 1 will take up a small portion of the lesson and most of the time can be used to solve a problem that introduces students to specific examples of indirect distance measurements and the achievements of modern science in the field of distance measurement.

The task of measuring distances to celestial bodies and their sizes is important for the formation of students’ ideas about the world and the possibility of knowing it. To fundamentally solve the problem, you need to guess that to measure the distance to an inaccessible object you can use the properties of similar triangles. Once this idea is expressed, it remains to find ways practical solution tasks. It is probably better to start with a practical solution to the problem using a model of the Moon. In the classroom, the role of the “Moon” can be played by any spherical body - a globe, a ball, a rubber ball - mounted on a demonstration table or mounted on a chalkboard. The author of the idea must provide an explanation of his solution using a drawing on the board. This drawing will serve as a guide for students when performing the task in practice.

To determine the distance from a point A, in which the observer is located, to an inaccessible point B note the direction of the straight line AB and move a certain measured distance to point C in a straight line perpendicular to the direction AB(Fig. 1). From a right triangle ABC required distance AB equals: AB = AC ·ctga. Since the distance AC measured, to calculate the problem you need to find the value ctga.

Rice. 1

Angle α = 90 - β can be determined by direct measurement of the angle β between straight lines C.A. And C.B. But it is more convenient to perform the following additional construction. Attach a sheet of white paper to a sheet of cardboard and place it on the student table so that the left edge of the sheet coincides with the straight line AB. We will check the coincidence by observing the coincidence of two pins stuck along the left edge of the sheet with the center of the “Moon” at the point IN. Then, without changing the position of the sheet on the table, move the eye to the right corner of the sheet. We stick the first pin into the right corner of the sheet, and the second at the intersection of the straight line connecting the first pin with the center of the “Moon”, with the far edge of the sheet.

After finding the distance to the celestial body, the problem of finding the size of the celestial body can be solved if it is possible to measure the angular diameter γ of the body. Let us denote the distance to the celestial body AB= L. Then the diameter D celestial body can be calculated from the measured angle γ, at which the diameter of the celestial body is visible from Earth, and the distance L:

D= L- tgy.

The tangent of the angle γ can be found by directing the scale ruler along the straight line AB and measuring the distance L, in which a coin with diameter d exactly covers the disk of the “Moon” (Fig. 2):

Measuring distances to celestial bodies. One of the students can be assigned in advance to prepare a report on measurements of distances to celestial bodies. This post should explain that when measuring distances from the Earth to other celestial bodies within the Solar System, the radius of the Earth is used as a basis. For measuring distances to the nearest stars, the Earth's radius is unsuitable as a basis, since the angle at which the Earth's radius is visible from a star turns out to be immeasurably small. Even the angle at which the radius of the earth's orbit is visible from a star turns out to be very difficult to measure.

It is possible to detect only the displacement of the stars closest to the Earth relative to the “fixed” stars as the Earth moves along its orbit around the Sun.

Short distance measurements. The second message can be assigned to the topic of measuring ultra-short distances. This will make it possible to evaluate the modern capabilities of physics in the field of measuring distances and linear dimensions of bodies both in the region of the megaworld and in the field of the microworld. Since information on measurements of ultra-short distances is not very easy to find, this topic can be entrusted to a student who has experience in searching necessary information on the Internet. The task can be formulated as follows: you need to find articles that describe the principle of operation scanning tunnel microscope, and talk about this device and the results obtained with its help.

In a scanning tunnel microscope, a metal tip of small diameter is installed above the surface of the body under study, and an electric field is created between the tip and the surface of the sample. Under the influence of an electric field, electrons are drawn out from the surface of the tip, but their possible distance from the end of the tip does not exceed the diameter of the atom. If the distance from the tip to the surface under study is less than 1 nm, then flow occurs between the tip and the surface. electric current. When the distance changes by the diameter of an atom, the current strength changes by a factor of 1000. This allows the current strength to very accurately determine the distance from the tip to the surface under study. If you move the tip in a straight line along a horizontally located surface and automatically maintain a constant current value in the circuit by moving the tip vertically, then the resulting curve of the dependence of the vertical coordinate of the tip on the horizontal will give a cut of the surface relief along one straight line. By repeating such sections step by step, you can obtain information about the structure of the surface and convert it into a three-dimensional picture on the computer screen.

The figure shows a picture of the structure of the surface of a silicon crystal obtained using a scanning tunneling microscope. The bumps and depressions in this picture show the structure of the outer electron shells of silicon atoms in the crystal.

Annotated bibliography

1. , Experimental tasks in physics. 9-11 grades: Textbook for students of general education institutions. - M.: Verbum, 2001.

The manual, aimed at developing the creative abilities of schoolchildren, presents a system of experimental tasks of varying complexity. Most of the tasks are designed to use very simple instruments and equipment, so the manual can be recommended for organizing independent experimental work. The first part of the book provides theoretical information about measurements of physical quantities and measurement errors necessary when planning an experiment, choosing a measurement method and measuring instruments, analyzing and evaluating the results of an experiment. The second part of the book contains descriptions of 22 experimental problems, for the solution of which knowledge of physics within the basic course is sufficient, but this knowledge must be applied in an unfamiliar situation and a creative approach must be used. The tasks in the third part of the book will allow students to conduct small experimental studies on their own.

2. Physics workshop for classes with in-depth study of physics: 10-11th grade/ Ed. , . - 2nd ed., revised. and additional - M.: Education, 2002.

The book offers descriptions of laboratory work in physics workshops for grades 10-11 of high school. The content of the workshop is aimed at students of specialized classes in which physics is one of the major subjects. On many topics, laboratory work is presented in several versions. The options differ both in the level of complexity and in the equipment used. This allows the teacher to choose from several proposed options one that corresponds to the objectives of this elective course, equipment physical office, interests and level of preparation of students. Descriptions of laboratory work are preceded by the theoretical chapter “Measurements of physical quantities and assessment of measurement errors.”

3. , Experimental problems in physics: 10-11 class general education institutions: Book. for the teacher. - M.: Education, 1998.

The book contains experimental problems and methodological instructions for a high school physics course. To carry them out, school equipment, household appliances and simple homemade devices can be used. The manual contains 260 tasks.

4. All-Russian Olympiads in Physics: 1992-2001/ Ed. CM. Kozela, . - M.: Verbum-M, 2002.

The book includes materials from all-Russian Olympiads for schoolchildren over 10 years. These are the conditions and solutions of theoretical and experimental tasks of the last two stages of the Olympiads (district and final). The manual is addressed to students in grades 9-11.

5. Eric Rogers. Physics for the curious. T.1. Matter, motion, force / Ed. - M.: Mir, 1969.

The author has set himself the goal of presenting the fundamentals of physics at an elementary level, doing it in such a way that the reader involuntarily feels like a participant in the process of finding and formulating the fundamental laws of nature. The historical background plays a significant role. The purpose of the book is to make the reader think, to reveal to him the internal mechanism of the development of science. The book is a valuable tool for physics teachers in schools; it can be usefully studied by inquisitive high school students.

6. Physics. 4.1: Universe/ Per. from English; edited by . - M.: Nauka, 1973.

The book is a useful addition to existing physics textbooks. It is intended for a wide range of readers: secondary school students, technical school students, people engaged in self-education, and is of great interest to physics teachers. “The Universe” is an extensive introduction to physics; the main content of the book is the fundamentals of kinematics and the atomic-molecular theory of the structure of matter with elements of the kinetic theory of gases. The book examines the fundamental concepts and methods of measuring time, space and matter, gives the first ideas about possible errors in measurements, approximate calculations, recording measurements and some modern measuring instruments.

Thematic planning of an elective course

(2 hours per week, total 14 hours)

Lesson number	Lesson topic	number of hours	date
	Introduction. Safety training
	Methods for measuring physical quantities
	Measurement errors
	Recording and processing of measurement results
	Laboratory work "Measuring I, U, R and P for a flashlight lamp"
	Laboratory work “Study of the dependence of T on ℓ, m and g of a mathematical pendulum”
	Laboratory work “Measuring the coefficient of friction”
	Study of the dependence of thermometer readings on external factors
	Blood pressure measurement
	Air humidity measurement
	Laser. Operating principle and design of a fluorescent lamp
	The design and principle of operation of an electric lighter
	Generalization. Application of knowledge in life
Total