Chapter 4. ELECTROMAGNETIC PHENOMENA
This chapter is devoted to various electromagnetic phenomena. The chapter consists of paragraphs and is devoted to the analysis of these phenomena.
Sources of light. Spread of light
Light is radiation, but only that part of it that is perceived by the eye. For this reason, light is called visible radiation.
The bodies from which light emanates are sources of light.
Light sources are divided into natural and artificial.
natural light sources- these are the Sun, stars, atmospheric discharges, as well as luminous objects of the animal and plant world.
artificial light sources, depending on what process underlies the production of radiation, are divided into thermal and luminescent.
TO thermal include light bulbs, gas burner flames, candles, etc.
Luminescent sources are fluorescent and gas light lamps
All light sources have dimensions. When studying light phenomena, we will use the concept of a point source of light.
If the dimensions of the luminous body are much smaller than the distance at which we evaluate its action, then the luminous body can be considered a point source.
Another concept that we will use in this section is a light beam.
A light beam is a line along which energy travels from a light source.
§ 64. Visible movement of the luminaries
The sun and the celestial bodies moving around it make up the solar system. The path that the Sun travels in a year against the background of stars is called ecliptic, and the period of one revolution along the ecliptic is called a sidereal year. The sun moves across the sky, moving from one constellation to another, and completes a complete revolution within a year.
Earth is one of the planets solar system. It revolves around the Sun in an elliptical orbit and revolves around own axis. The movement of the Earth around the Sun and some tilt of the Earth's axis lead to the change of seasons. When the Earth moves around the Sun, the Earth's axis remains parallel to itself.
Moon the satellite closest to the earth heavenly body. It revolves around the Earth in the same direction as the Earth around its axis, and together with the Earth revolves around the Sun.
All planets revolve around the sun in the same direction. The planet, moving in the same direction as the Sun and the Moon, after a while slows down its course, then stops, moves in the opposite direction and after the next stop again changes the direction of movement to the original one.
§ 65. Reflection of light. Law of light reflection
You already know that light from a source or from an illuminated body is perceived by a person if the rays of light enter the eyes. From the source S, let's direct a beam of light through the slit onto the screen. The screen will be illuminated, but we will not see anything between the source and the screen (Fig. 134, a). Now let's place an object between the source and the screen: a hand, a piece of paper. In this case, the radiation, having reached the surface of the object, is reflected, changes its direction and enters our eyes, i.e., it becomes visible.
Rice. 134. Rays of light falling on the screen
If the air is dusted between the screen and the light source, then the entire beam of light becomes visible (Fig. 134, b). Dust particles reflect light and direct it to the eyes of the observer.
This phenomenon is often observed when the rays of the sun penetrate the dusty air of the room.
It is known that on a sunny day with the help of a mirror you can get a light "bunny" on the wall, floor, ceiling. This is explained by the fact that a beam of light, falling on a mirror, is reflected from it, that is, it changes its direction.
A light spot is a trace of a reflected beam of light on a screen. Figure 135 shows the reflection of light from a mirror surface.
Rice. 135. Reflection of light from a mirror surface
Line MN - the interface between two media (air, mirror). A beam of light falls on this surface from point S. Its direction is given by the ray SO. The direction of the reflected beam is shown by the OB beam. Beam SO - incident beam, beam OB - reflected beam. From the point of incidence of the ray O, the perpendicular OS to the surface MN is drawn. The angle SOC formed by the incident ray SO and the perpendicular, called the angle of incidence(α). The COB angle formed by the same perpendicular OS and the reflected beam is called reflection angle (β).
Thus, the reflection of light occurs according to the following law: the incident and reflected rays lie in the same plane with a perpendicular drawn to the interface between the two media at the point of incidence of the beam.
The angle of incidence α is equal to the angle of reflection β.
∠ α = ∠ β.
Any non-specular, i.e., rough, non-smooth, surface scatters light, since it has small protrusions and depressions.
§ 66. Flat mirror
flat mirror A flat surface that reflects light is called a flat surface. The image of an object in a flat mirror is formed behind the mirror, i.e., where the object does not exist in reality.
Let diverging rays SO, SO 1, S0 2 fall on the mirror MN from a point source of light S (Fig. 139).
According to the law of reflection, the beam SO is reflected from the mirror at an angle of 0°; beam S0 1 - at an angle β 1 = α 1 ; beam S0 2 is reflected at an angle β 2 = α 2 . A divergent beam of light enters the eye. If we continue the reflected rays behind the mirror, then they will converge at the point S 1. A divergent beam of light enters the eye, as if emanating from point S 1 This point is called imaginary image of the point S.
Rice. 139. Image of an object in a flat mirror
S 1 O = OS. This means that the image of the object is at the same distance behind the mirror as the object is in front of the mirror.
§ 67. Refraction of light. Law of refraction of light
A medium in which the speed of light propagation is lower is an optically denser medium.
Thus, the optical density of the medium is characterized by different speeds of light propagation.
This means that the speed of light propagation is greater in an optically less dense medium. When a light beam falls on a surface separating two transparent media with different optical densities, such as air and water, part of the light is reflected from this surface, and the other part penetrates into the second medium. When passing from one medium to another, a beam of light changes direction at the boundary of the media (Fig. 144). This phenomenon is called refraction of light.
Rice. 144. Refraction of light when a beam passes from air to water
Consider the refraction of light in more detail. Figure 145 shows: incident beam AO, refracted beam OB and perpendicular to the interface between two media, drawn to the point of incidence O. Angle AOC - angle of incidence (α), angle DOB - angle of refraction (γ).
A beam of light, when passing from air to water, changes its direction, approaching the perpendicular CD.
Water is an optically denser medium than air. If water is replaced by some other transparent medium, optically denser than air, then the refracted beam will also approach the perpendicular. Therefore, we can say that if light goes from an optically less dense medium to a denser medium, then the angle of refraction is always less than the angle of incidence
A beam of light directed perpendicular to the interface between two media passes from one medium to another without refraction.
When the angle of incidence changes, the angle of refraction also changes. The larger the angle of incidence, the larger the angle of refraction
In this case, the relationship between the angles is not preserved. If we make the ratio of the sines of the angles of incidence and refraction, then it remains constant.
For any pair of substances with different optical density, we can write:
where n is a constant value independent of the angle of incidence. It is called refractive index for two environments. The greater the refractive index, the more the beam is refracted when passing from one medium to another.
Thus, the refraction of light occurs according to the following law: the rays of the incident, refracted and the perpendicular drawn to the interface between two media at the point of incidence of the beam lie in the same plane.
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant value for two media:
§ 68. Lenses. Optical power of the lens
Lenses are transparent bodies bounded on both sides by spherical surfaces.
There are two types of lenses - convex and concave.
Rice. 151. Types of lenses:
a - convex; b - concave
The straight line AB passing through the centers C 1 and C 2 (Fig. 152) of the spherical surfaces that bound the lens is called optical axis.
Rice. 152. Optical axis of the lens
By directing a beam of rays parallel to the optical axis of the lens to a convex lens, we will see that after refraction in the lens, these rays intersect the optical axis at one point (Fig. 153). This point is called lens focus.
Each lens has two foci, one on each side of the lens.
Rice. 153. Converging lens:
a - the passage of rays through the focus; b - its image on the diagrams
The distance from a lens to its focus is called lens focal length and is marked with the letter F.
A convex lens collects rays coming from a source. Therefore, a convex lens is called gathering.
Such a lens is called scattering.
Rice. 154. Diverging lens:
a - the passage of rays through the focus; b - its image on the diagrams
Lenses with more convex surfaces refract rays more than lenses with less curvature. If one of the two lenses has a shorter focal length, then it gives a greater magnification. The optical power of such a lens is greater.
Lenses are characterized by a value called the optical power of the lens. Optical power is denoted by the letter D.
The optical power of a lens is the reciprocal of its focal length..
The optical power of the lens is calculated by the formula
The unit of optical power is the diopter (dptr).
1 diopter is the optical power of a lens with a focal length of 1 m.
§ 69. Images given by a lens
With the help of lenses, you can not only collect or scatter light rays, but also obtain various images of an object. If we place a candle between the lens and its focus, then on the same side of the lens where the candle is located, we will see an enlarged image of the candle, its direct image
If the candle is placed behind the focus of the lens, then its image will disappear, but on the other side of the lens, far from it, a new image will appear. This image will be enlarged and inverted in relation to the candle.
If you bring an object closer to the lens, then its inverted image will move away from the lens, and the size of the image will increase. When the object is between points F and 2F, i.e. F< d < 2F, его действительное, увеличенное и перевёрнутое изображение будет находиться за двойным фокусным расстоянием линзы (рис. 159)
If the object is placed between the focus and the lens, i.e. d< F, то его изображение на экране не получится. Посмотрев на свечу через линзу, мы увидим imaginary, direct And enlarged image.It is between focus and double focus, i.e.
F< f < 2F.
Thus, the size and location of the image of an object in a converging lens depend on the position of the object relative to the lens.
§ 70. Eye and vision
The human eye has an almost spherical shape, it is protected by a dense shell called the sclera. The anterior part of the sclera - the cornea 1 is transparent. Behind the cornea (cornea) is the iris 2, which different people may have a different color. Between the cornea and the iris is a watery fluid.
Rice. 163. Human eye
There is a hole in the iris - the pupil 3, the diameter of which, depending on the lighting, can vary from about 2 to 8 mm. It changes because the iris is able to move apart. Behind the pupil there is a transparent body, similar in shape to a converging lens - this is the lens 4, it is surrounded by muscles 5 that attach it to the sclera.
Behind the lens is the vitreous body 6. It is transparent and fills the rest of the eye. The back of the sclera - the fundus - is covered with a retina 7 (retina). The retina consists of the finest fibers, which, like villi, cover the fundus of the eye. They are branched endings of the optic nerve that are sensitive to light.
Light falling into the eye is refracted on the anterior surface of the eye, in the cornea, lens and vitreous body (i.e., in the optical system of the eye), due to which a real, reduced, inverted image of the objects under consideration is formed on the retina (Fig. 164).
Rice. 164. Image formation on the retina
Light falling on the endings of the optic nerve that make up the retina irritates these endings. Irritations are transmitted along the nerve fibers to the brain, and the person receives a visual impression, sees objects. The process of vision is corrected by the brain, so we perceive the object straight.
And how is a clear image created on the retina when we shift our gaze from a distant object to a close one, or vice versa?
In the optical system of the eye, as a result of its evolution, a remarkable property has been developed that provides an image on the retina at different positions of the object. What is this property?
The curvature of the lens, and hence its optical power, can change. When we look at distant objects, the curvature of the lens is relatively small, because the muscles surrounding it are relaxed. When looking at nearby objects, the muscles compress the lens, its curvature and, consequently, the optical power increase.
Task 63.1
Complete the diagram containing information about light sources. (Do the work with a simple pencil.)
Task 63.2
Fill in the gaps in the text.
One type of heat transfer is radiation. The radiation we see is called light. Light can propagate both in air and liquids, and in vacuum.
Sources of light are bodies from which comes out light. If the size of the luminous body is much smaller than the distance at which we evaluate its action, then the luminous body can be considered pinpoint light source. For example, huge stars are perceived by us as point light sources, as they are from us on big distance.
Task 63.3
Fill in the gaps in the text.
a) It is called a light beam line, along which it propagates energy from a light source. In a homogeneous medium, the beam propagates straightforward, and in a heterogeneous one, other options are possible.
b) Formulate how the shadow differs from the penumbra.
In the penumbra, the light enters partially, but not at all in the penumbra.
Task 63.4
The figure shows two light sources, a fixed tennis ball and a screen. Source S1 is a small bulb that emits red light, source S2 emits blue light.
Task 63.5
The pictures show mutual arrangement Moon (L), Earth (W) and Sun (S).
a) In each figure, draw straight lines with a yellow pencil showing the possible directions of propagation of visible energy from point B and circle with a yellow pencil the areas where visible energy from this point does not fall.
b) do it similar work green pencil with dot H.
c) With a simple pencil, paint over the area where visible radiation coming from the Sun does not fall.
d) With a stroke, paint over the areas that are penumbra.
e) Answer the questions.
What is the name of the area you painted in gray?
Shadow
What is the name of the phenomenon shown in Figure a;
Moon eclipse.
In figure b?
Solar eclipse.
Test(test) in physics for intermediate certification for academic year contains:
- Answer form (filled in on both sides). Criteria for evaluation. Answers. Solutions of problems of part 3. Task options (1,2,3). Sample brief analysis control works.
Test
in physics (test)
for intermediate certification
per academic year
student(s) 8 " " class
_____________________________
Answer sheet.
Part 1.
Job number
Part 2.
16.
A
17.
A
Part 3
18.
Criteria for evaluation.
Final work consists of three parts.
Part 1 consists of 15 test items.
For each of 1-15 tasks, 4 answers are given, of which only one is correct.
Each task is worth one point.
Part 2 consists of two tasks.
In tasks 16, 17 it is necessary to establish a correspondence between physical quantities and formulas, or units of measurement of these quantities.
Each task is worth two points if it is completed completely, one point is given if one wrong answer is given.
Part 3 consists of one task.
When completing task 18, it is necessary to correctly solve and formulate the problem.
Task 18 is worth three points if the task is solved completely. Two points are given if the task is correct, but a complete answer is not given (calculations were not completed to the end, there is no answer). One point is given if the task is correctly framed and the calculation formulas are written correctly.
Point conversion scale.
Maximum amount points - 22 points.
Mark by
five-point scale
Criteria for evaluation. Giving marks for the work done. Grade "2" is placed if the student scored less than 6 points for the entire work.Grade "3" is put in the event that the student scored from 6-10 points.Rating "4" is set if the student scored from 11-15 points, provided that one task from part 2 was completed correctly.Rating "5" is set if the student scored from 16-22 points, provided that all the tasks of part 2 are correctly completed, or one task of part 2 and the task of part 3 are completed (fully or partially).
Answers. Part 1.
Job number
Part 2.Job number
Part 3 Option 1. Using the formula for determining the resistance of the conductor, the current power, Ohm's law for the circuit section and tabular values, we get:P= UI or P= U 2 / R from here we find the resistance: R=U2/P , substitute in the formula for calculating the length of the conductor: L= U 2 S/ pPPlugging in the data: L=200V*200V*0.5mm 2 /0.4*360W=138.9m ANSWER: 138.9m Option 2. Using the rules for connecting conductors and Ohm's law for a circuit section: U 1 \u003d U 2 \u003d U, I \u003d U / R Let's determine the current strength in each section of the circuit: I 1 = U/ R 1 I 2 = U/ R 2 Let's find the ratio of the current strength: I 2 / I 1 = UR1 / UR2 or I2 / I1 = R1 / R2 Let's plug in the data: I2 / I1 =150/30=5 times ANSWER: the current strength in the second conductor is 5 times greater. Option 3. Using the formula for resistance, cross-sectional area, Ohm's law for the circuit section and tabular data, we get:
R=U/I Find the cross-sectional area:S= pLI/ ULet's plug in the data: S=1.1*5*2/14=0.79mm2 ANSWER: 0.79mm 2
Option 1. Part 1.
1. During processing on the machine, the part is heated. What happened to her internal energy?
1) did not change 2) increased as a result of heat transfer 3) increased due to work 4) decreased due to heat transfer
2. What type of heat transfer is accompanied by the transfer of matter?
1) thermal conductivity 2) convection 3) radiation 4) thermal conductivity and radiation
3. During the transition of a substance from a liquid state to a solid
1) the forces of attraction between particles increase 2) potential energy the interaction of particles does not change 3) the kinetic energy of the particles decreases 4) the order in the arrangement of particles increases
4. The specific heat capacity of ice is 2100 J / kg O WITH . How did the internal energy of 1 kg of ice change when cooled by 1 O WITH?
1) increased by 2100J 2) decreased by 2100J 3) did not change 4) decreased by 4200J
5. Internal energy of an evaporating liquid
1) does not change 2) decreases 3) increases 4) depends on the type of liquid
6. Around the motionless electric charges exists
1) electric field 2) magnetic field 3) electric and magnetic field 4) gravitational field
7. There are 5 electrons in an atom, and 6 neutrons in the nucleus of this atom. How many particles are in the nucleus of this atom?
1)5 2)6 3)11 4)16
8. The movement of what particles creates an electric current in metals?
1) electrons 2) protons 3) ions 4) neutrons
9. What is the current strength in an electric lamp with a resistance of 10 ohms at a voltage of 4V at its ends?
1) 40 A 2) 2.5 A 3) 0.4 A 4) 0.04 A
10. A magnetic field exists around
1) stationary electric charges 2) any bodies 3) moving electric charges 4) interacting electric charges
11. The magnetic effect of the current coil can be enhanced if
1) reduce the current in it 2) insert an iron core into the coil 3) insert a wooden core into the coil 4) reduce the number of turns in the coil
12. If the dimensions of the luminous body are much less than the distance at which its action is evaluated, then it is called
1) artificial 2) luminescent 3) spot 4) ideal
13. Angle of incidence of light on the water surface 25 0 . What is the angle between the incident and reflected rays?
1)25 0 2)30 0 3)60 0 4)90 0
14. Image of an object in a flat mirror
1) imaginary, equal to the object 2) real, equal to the object 3) real, of any size 4) imaginary, of any size
15. The phenomenon of light refraction is due to the fact that
1) the speed of light is the same in all media 2) the speed of light is very high 3) the speed of light is different in various environments 4) light travels very slowly
Part 2.
16. Establish a correspondence between physical quantities and formulas for their calculation.
PHYSICAL QUANTITIES
A
17. Establish a correspondence between units of measurement and physical quantities. For each position of the first column, select the corresponding position of the second and write down the selected numbers in the table under the corresponding letters.
UNITS
Part 318. How many meters of nickel wire with a cross section of 0.5 mm 2 required for the manufacture of a heating element with a power of 360W, designed for a voltage of 200V?
Final test in physics, 8th grade. Option 2. Part 1.
For each of the tasks 1-15, 4 answers are given, of which only one is correct. Specify it.
1. Water is heated in a vessel. What can be said about its internal energy?
1) internal energy has not changed 2) internal energy has decreased 3) internal energy has increased 4) there is no correct answer
2. What materials, dense or porous, have the best thermal insulation properties? Why?
1) dense, because there are no holes for air to pass through 2) dense, because molecules are located close to each other 3) porous, because due to the holes, their volume increases 4) porous, because pores contain air with poor thermal conductivity
3. Hot and cold water were mixed in a vessel. Compare the change in their internal energies.
1) the internal energies have not changed 2) the internal energy of hot water has increased more than the internal energy has decreased cold water 3) how much the internal energy of hot water decreased, by the same amount the internal energy of cold water increased 4) the internal energy of hot water decreased more than the internal energy of cold water increased
4. When burning fuel mass m amount of heat released Q . The specific heat of combustion of fuel can be calculated by the formula
1) Qm 2) Qt / m 3) Q / mt 4) Q / m
5. For what type of vaporization - evaporation or boiling - is necessary external source energy?
1) evaporation 2) boiling 3) boiling in a closed vessel 4) boiling and evaporation
6. An ebonite stick was rubbed against wool. What can be said about the charges acquired by the stick and wool?
1) both positive 2) rod-positive, wool-negative 3) both negative 4) rod-negative, wool-positive
7. Electric current in metals is an ordered movement
1) electrons 2) protons 3) ions 4) charged particles
8. An electric current source is needed for
1) creating an electric current 2) creating electric field 3) creating an electric field and maintaining it for a long time 4) maintaining an electric current in the circuit
9. There are 12 particles in the nucleus of a carbon atom, of which 6 are neutrons. How many electrons are moving around the nucleus?
1)6 2)12 3)0 4)18
10. Around the conductor with current can be found
1) electric field 2) magnetic field 3) electric and magnetic field
4) only gravitational field
11. How many poles does a coil with current have?
1) none 2) one-northern 3) one-south 4) two-north and south
12. The light beam is a line,
1) along which light moves 2) along which energy propagates from the source 3) along which radiation propagates 4) along which we look at the source
13. The angle between the surface of the mirror and the incident beam is 30 0 . What is the angle of reflection?
1)30 0 2)45 0 3)60 0 4)90 0
14. Distances from the object to the flat mirror and the distance from the mirror to the image
1) equal 2) more than 2 times 3) less than 2 times 4) differ by 4 times
15. On the basis of what law can one explain the “break” of a spoon dipped into a glass of water at the air-water boundary?
1) the law of rectilinear propagation of light 2) the law of reflection of light 3) the law of refraction of light 4) none of the laws explains
Part 2.
16. Establish a correspondence between physical quantities and their units of measurement.
For each position of the first column, select the corresponding position of the second and write down the selected numbers in the table under the corresponding letters.
PHYSICAL QUANTITIES
17.PHYSICAL QUANTITIES
Part 3
When completing task 18, it is necessary to correctly formulate the task.
18. Two conductors are connected in parallel in the circuit. The resistance of one is 150 ohms, the other 30 ohms. In which conductor is the current greater and by how much?
Final test in physics, grade 8. Option 3. Part 1.For each of the tasks 1-15, 4 answers are given, of which only one is correct. Specify it.
1. The steel ruler is hit with a hammer. How does the internal energy of the ruler change in this case?
1) heat transfer 2) doing work 3) heat transfer and doing work 4) radiation
2. In what bodies can convection occur?
1) in solids 2) in liquids 3) in gases 4) in liquids and gases
3. What methods of heat transfer play a major role in gases?
1) conduction and convection 2) conduction and radiation 3) convection and radiation 4) conduction, convection and radiation
4. Copper melts. How does this change its internal energy?
1) increases 2) decreases 3) does not change 4) becomes zero
5. How will the rate of evaporation of liquid change with increasing temperature?
1) will increase 2) will decrease 3) will not change 4) cannot be said for certain
6. If two identical charged balls are attracted to each other, then
1) they are positively charged 2) they are negatively charged 3) one of them is negatively charged and the other positively 4) they may not have charges
7. There are 5 protons and 6 neutrons in the nucleus of an atom. How many electrons are in this atom?
1)1 2)5 3)6 4)11
8. Electric current is called
1) random movement of particles of matter 2) directed movement of particles of matter 3) directed movement of charged particles 4) directed movement of electrons
9. What is the formula for calculating the voltage at the ends of the conductor?
1)I=U/R 2)U=IR 3)P=IU 4)A=P/t
10. Deviation of a magnetic needle located near a current-carrying conductor is
1) mechanical phenomenon 2) electrical phenomenon 3) magnetic phenomenon 4) thermal phenomenon
11. A coil with an iron core inside is called
1) capacitor 2) dielectric 3) electromagnet 4) relay
12. How is the law of rectilinear propagation of light formulated?
1) light always propagates in a straight line 2) light in a transparent medium propagates in a straight line 3) light in a transparent homogeneous medium propagates in a straight line 4) from a point source light propagates in a straight line
13. The angle of incidence of the light beam was increased by 15 0 . How has the angle of reflection changed?
1) increased by 15 0 2) decreased by 15 0 3) increased by 30 0 4) decreased by 30 0
14. A point source of light is located at a distance of 10cm from a flat mirror. How far is his image from the mirror?
1)5cm 2)10cm 3)15cm 4)20cm
15. The phenomenon of the transition of a light beam from one medium to another with a change in the direction of propagation of the beam is called
1) reflection 2) refraction 3) absorption 4) diffraction
Part 2.
PHYSICAL QUANTITIES
17. Establish a correspondence between physical quantities and formulas for their calculation. For each position of the first column, select the position of the second and write down the selected numbers in the table under the corresponding letters.Part 3
When completing task 18, it is necessary to correctly formulate the task.
18. Find the cross-sectional area of \u200b\u200bthe nichrome wire, if at a voltage of 14V the current in it is 2A. Wire length 5m.
Analysis of tests in physics (test) for intermediate certification for the academic year. Class : 8 a, b, c.Quantity : students.General academic performance : % Qualitative academic performance : % Job grades :
"5"
Completely correctly completed the work ________, scored (a) 22 points out of 22 possible.____________ scored 21 points out of 22.Part 1 was completed by all students. Main mistakes in part 1 (often encountered):- Recognition of physical phenomena Definition of thermal processes. Determination of electrical quantities. Knowledge of Ohm's law for a circuit section. Determination of the angles of incidence and reflection (the law of reflection of light).
- On the correspondence of formulas and units of measurement. On the correspondence of physical quantities and units of measurement.
Nikolskaya secondary school
Compiled by: teacher of physics and computer science
Nikolskaya secondary school
Spassky district
Republic of Tatarstan
Avdonina V.P.
8th grade
Physical dictations of the 1st type.
Select from the listed concepts units of measurement, physical quantities, devices, phenomena, processes. Present your answer in the form of a table:
units | physical quantities | devices | processes |
joule, energy, free fall, diffusion, speed, temperature, С, m/s, potential energy, strain, internal energy;
heat transfer, calorie, thermometer, beaker, calorimeter, convection, kg, heat capacity, mass, J/kg, C, temperature, thermal conductivity, amount of heat;
melting, specific heat of fusion, specific heat of combustion of fuel, mg, scales, vaporization, amount of heat, J/kg,Q, boiling, specific heat of vaporization
humidity, psychrometer, relative air humidity, hair hygrometer, С, temperature, %, evaporation, condensation;
current,R, ampere, milliammeter, electrical voltage, voltmeter, Ohm, rheostat, resistivity, m, mm 2 , cross-sectional area;
work of electric current, joule. Watt, electric current power, wattmeter, kW h,I, A, key, resistor, electric bell, amount of heat;
electric motor, electromagnet, ammeter, rheostat, ampere, ohm,
light reflection, diopter, diopter, optical power, focus, light refraction, meter,D, lens, solar eclipse, shadow, 3 10 8 m/s.
physical dictations II type
Select from the listed concepts, words, phrases associated with phenomena. Present your answer in the form of a table:
thermal and electrical phenomena
electrization, convection, heat capacity, heat transfer, current strength, electric charge, electron, charge divisibility, radiation, specific heat of fusion, heat transfer, Ioffe-Miliken experiment, Ohm's law, resistance, joule, Joule-Lenz law, specific heat of combustion of fuel, proton , neutron, E. Rutherford, electric field;
electrical and magnetic phenomena
magnetic field, pole, watt, resistivity, current power, lines of force, ampere, B. Jacobi, electromagnet, uniform field, electric current work, 1 Ohm, A.M. Ampere, A. Volta, G. Oersted, compass, northern lights, KMA, D. Maxwell, rheostat, permanent magnet, kW, fuse, short circuit, Lodygin, pole, Edison;
magnetic and light phenomena
straightness of propagation, pole, ammeter, reflection, flat mirror, compass, refraction, lens, Oersted, focus, optical power, shadow, eclipse, iron filings, flying Dutchman, diopter, image, 3 10 8 m/s, focal length,D, lines of force, core, anchor, magnifier, scattering, microscope.
Physical dictation III type
Fill in the missing words or complete the sentence.
Subject: Internal energy.
A molecule is the smallest particle ...... (substance)
there are two types of mechanical energy that atoms have: ... .. (kinetic and potential).
The energy of movement and interaction of the particles that make up the body is called .... (internal energy)
The internal energy of the body.... from its mechanical energy. (does not depend).
When the temperature of a body rises, its internal energy .... (increases).
The transfer of energy from more heated parts of the body to less heated ones due to the thermal motion of particles is called ... (thermal conductivity).
When bending and unbending an aluminum wire, its internal energy changes in a way .... (work on the body).
Among metals, the highest thermal conductivity is ... (silver, gold).
Porous bodies have poor thermal conductivity, as they contain ... (air).
Transfer of heat in a vacuum by conduction ... (impossible).
IN solids convection to occur, ... (cannot).
The transfer of energy from the Sun to the Earth is carried out by ... (radiation).
Bodies with a dark surface ... absorb the energy of radiation falling on them. (Fine)
For convection to occur in water, it must be cooled ... or heated ... (from above, below).
Subject: thermal phenomena
The energy that a body receives or loses during heat transfer is called ... (amount of heat).
The unit of heat quantity is called … (joule).
The specific heat capacity of water is ... (4200 J / kg WITH).
The specific heat capacity of the same substance in different states of aggregation... (different).
Melting is the transition of a substance ... (from a solid to a liquid state).
The amount of heat released during the complete combustion of 1 kg of fuel is called ... (specific heat of combustion of fuel).
At the melting point, the internal energy of water, ... the internal energy of the same mass of ice at 0 S. (more)
When ice melts, its temperature ... (does not change).
The crystallization process is accompanied by … heat. (selection)
The formula for the amount of heat required to melt a substance ... (Q= m)
TO amorphous bodies include, for example ... (glass, rosin, lollipop)
Amorphous bodies ... of a certain melting point. (Dont Have)
The reverse process of vaporization is called ... (condensation)
Dew formation. Clouds are associated with such a thermal phenomenon as ... .(condensation)
Condensation is accompanied by … energy. (selection)
The amount of heat required to convert 1 kg of liquid at the boiling point into steam is called ... (specific heat of vaporization)
During boiling, the temperature of the liquid ... (does not change)
boiling and condensing temperature for given substance… (same)
Subject: electrical phenomena.
Electron is translated from Greek as ... (amber)
The process of separation of charges is called ... (electrification)
There are two types of charges: ... (positive and negative)
Charges of the same name ..., and opposite charges ... (repel, attract)
Electric charge is divided into ... parts. (equal)
One way to electrify is ... (friction)
A device for measuring electric charge is called ... (electrometer)
The minimum electric charge is ... (1.6 10 -19 Cl)
Part atomic nucleus includes ... (protons and neutrons)
The idea of the atomic nucleus belongs to ... (E. Rutherford)
A special kind of matter is formed around a charged body, which is called ... (electric field)
Electrification is used, for example ... (when painting car bodies, when smoking.)
The study of the interaction of electric charges was carried out English physicists: ... and ... (D. Maxwell and M. Faraday)
The unit of electric charge is named after the French physicist ... (Sh.O. Coulomb)
Subject: Electric current. Current strength.
Topic: Electrical voltage.
Voltage is a physical quantity that characterizes ..., which creates a current. (electric field)
Voltage shows ... when moving an electric charge equal to 1 C. (current work)
The value is equal to the ratio of the work of the current in this section to electric charge passing through this section is called ... (voltage)
The unit of voltage is taken ... (volt)
The unit of voltage is named after the Italian scientist ... (A. Volta)
1 V = ... (1J/ Cl)
The lighting network uses voltage ... (220 V)
To measure voltage, a device called ... (voltmeter) is used.
The clamps of the voltmeter are connected to those points of the circuit between which the voltage must be measured, such an inclusion of the device is called ... (parallel)
The current in the circuit is directly proportional to ... (voltage at the ends of the circuit)
The voltage is indicated by the letter of the Latin alphabet - ... (U)
Subject: Electrical resistance.
The strength of the current in the circuit depends not only on the voltage, but also on ... (properties of the conductor)
The dependence of the current strength on the properties of the conductor is explained by various ... (resistance)
The unit of resistance is taken ... (Ohm)
Unit electrical resistance conductor is named after the German physicist ... (G. Ohm)
The reason for the resistance of the conductor is ... (the interaction of moving electrons with ions of the crystal lattice)
The strength of the current in the conductor is inversely proportional to ... (its resistance)
The current strength in a circuit section is directly proportional to the voltage at the ends of this section and inversely proportional to its resistance - this is the law ... (Ohm)
How many times the resistance of the conductor increases, how many times it decreases ... with the same ... (current strength in the conductor, voltage at the ends of the conductor)
The resistance of a conductor made of a given substance 1 m long, with a cross-sectional area of 1 m 2 called ... (resistivity)
The device for regulating the current strength in the circuit is called ... (rheostat)
Topic: Parallel and series connection of conductors
A connection in which the end of one section is connected to the beginning of the next, and forms a closed loop, is called ... (serial)
An example of a serial connection is the connection of ... (light bulbs in a Christmas tree garland)
With a series connection, the current strength in any parts of the circuit ... (the same)
The total resistance of the circuit when connected in series is ... (the sum of the resistances of its individual sections)
The total voltage in the circuit when connected in series, or the voltage at the poles of the current source, is ... (the sum of the voltages in individual sections of the circuit)
A connection in which all the conductors included in it are connected with one end to one point, and the other end to another point is called ... (parallel)
An example of a parallel connection is the connection of ... (lights and sockets in the apartment)
The voltage at the circuit section and at the ends of all parallel-connected conductors .... (same)
The current strength in the unbranched part of the circuit is ... in separate parallel-connected conductors. (sum)
The reciprocal of resistance is called ... (conductivity)
With a parallel connection, the conductivity of the entire circuit is equal to ... the conductivity of its individual sections. (sum)
Topic: Work and power of electric current.
To determine the work of an electric current in any section of the circuit, it is necessary ... (multiply the voltage at the ends of this section of the circuit by the electric charge)
The work of an electric current in a section of the circuit is ... (the product of the voltage at the ends of this section, the current strength and the time during which the work was done)
The power of the electric current is ... (the product of voltage and current strength)
Per unit of power accepted .. (watt)
1 W = ... (1 J/ With)
To measure the power of electric current, devices are used - ... (wattmeters)
1 kW h \u003d ... J. (3600000 J)
Joule-Lenz law - .... (the amount of heat released by a conductor is equal to the product of the square of the current, the resistance of the conductor and time)
A lamp suitable for industrial production with a carbon filament was created by an American inventor .... (T. Edison)
An electric incandescent lamp was created by a Russian engineer ... (A.N. Lodygin)
The connection of the ends of a section of a circuit with a conductor whose resistance is very small compared to the resistance of the circuit is called ... (short circuit)
The purpose of the fuses ... (immediately turn off the line if the current strength is greater than the permissible norm)
Fuses with a consumable conductor are called ... (fusible)
A device for measuring the work of an electric current is called ... (meter)
Subject: magnetic phenomena.
Interaction forces arise between conductors with current, which are called ... (magnetic)
The interaction of a conductor with current and a magnetic needle was first discovered by a Danish scientist ... (Oersted)
Around the conductor with electric shock exists ... (magnetic field)
source magnetic field serves ... (moving charge)
The magnetic field around a conductor with current can be detected for example ... (using a magnetic needle, using iron filings)
The lines along which the axes of small magnetic arrows are located in a magnetic field are called ... (magnetic lines of force)
the magnetic lines of a magnetic field are ... curves that enclose a conductor. (closed)
A coil with an iron core inside is called ... (electromagnet)
The magnetic field of a coil with current can be strengthened if, ... (increase the current strength, increase the number of turns in the coil, insert a core)
Electromagnets are used, for example ... (in telephones, telegraphs, magnetic relays)
Bodies that retain their magnetization for a long time are called ... (permanent magnets)
Every magnet must have ... (pole)
The same poles of a magnet ..., and the opposite poles - ... (repel, attract)
The Earth has... (a magnetic field)
Earth's magnetic poles ... with its geographic poles. (do not match)
One of the largest magnetic anomalies is ... (Kursk)
The compass was invented in ... (China)
The rotation of a coil with current in a magnetic field is used in the device ... (electric motor)
One of the world's first electric motors suitable for practical application, was invented by a Russian scientist ... (B.S. Jacobi)
Subject: light phenomena.
Light is ... (visible radiation)
Light sources are divided into ... and ... (natural and artificial)
If the dimensions of the luminous body are much smaller than the distance at which we evaluate its action, then the luminous body is called ... (point source)
A light beam is a line, ... (along which light travels)
A shadow is that area of \u200b\u200bspace, ... (into which light from a source does not fall)
Penumbra is that region of space, ... (into which light enters from part of the source)
When the Moon falls into the shadow of the Earth, then ... (lunar eclipse) is observed
When the shadow of the moon falls on the Earth, at this place on Earth there is ... (solar eclipse)
The angle between the incident beam and the perpendicular restored at the point of incidence of the beam to the interface between two media is called ... (angle of incidence)
The angle of incidence is ... (the angle of reflection)
The imaginary image of an object in a flat mirror is ... the distance from the mirror at which the object itself is located. (on the same)
Dimensions of the image of an object in a flat mirror ... (equal)
The optical density of the medium is characterized by ... the propagation of light. (speed)
A change in the direction of light propagation at the interface between two media is called ... (refraction)
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is ... (the value is constant for these two media)
Transparent bodies bounded on both sides by spherical surfaces are called ... (lenses)
There are two types of lenses: ... (convex and concave)
Lenses whose edges are thicker than the middle are ... (concave)
A lens whose edges are much thinner than the middle is ... (convex)
Each lens has two ... - one on each side. (focus)
A convex lens is called ..., and a concave lens is called ... (collecting, scattering)
The reciprocal of the focal length of a lens is called ... (optical power)
IfF< d<2 F, then the image will be ... (real, enlarged, inverted, located on the other side of the lens)
Ifd>2 F, then the image will be ... (real, inverted, reduced, located on the other side of the lens)
Ifd< F, then the image will be ... (imaginary, direct, enlarged, located on one side of the lens)
Lenses are used in devices, for example: ... (microscope, camera, telescope)
Physical dictation + physical education minute (for students in grades 7.8)
Physical quantity, its designation, unit of measurement, instrument, formula, term associated with physical quantity etc. corresponds to a suitable physical exercise (the exercise can be performed while sitting)
force - arms are bent at the elbows, demonstrating their muscles ("strong men")
time - look at the hand, bending it at the elbow, imitating the movement when looking at the watch worn on the hand;
speed - simulate running;
length, path - hands to the side;
height - hands up;
temperature - rubbing hands;
volume - spread their arms to the side, showing the volume of the ball;
weight - raise their hands up, simulating the movement when lifting the barbell;
density - show two exercises in a row related to mass and volume
pressure - rise on a chair on their hands
Job - do two exercises in a row related to strength and path
energy - jumping in place
Children are happy to come up with such exercises.
Seven troubles, one answer. (based on the TV game of the same name)
Seven signs for one:
thermal phenomena
1.1). Physical quantity
2). Hot - cold
3). Thermal phenomena are associated with its change
4).if it rises, then the molecules move faster
5). Degree Celsius
6). If it rises with us, we get sick
7). It is measured with a thermometer
answer: temperature
2.1).thermal movement
2).molecules
3). Depends on aggregate state
4) deformation
5). Does not depend on the mechanical movement of the body
6). Very large
7). Can be changed in two ways
Answer: internal energy
3.1). It happens bad and good for different substances
2). Vacuum
3). "Is the fur coat warm"
4). "Puffed up like a sparrow"
5). Good for metals
6). The phenomenon of internal energy transfer
Answer: thermal conductivity
4.1). Phenomenon
2). Wind
3). Is natural and free
4). Cannot occur in solids
5). Needs to be heated from below
6). Energy is carried by jets of gas or liquid
7). Type of heat transfer
answer: convection
5.1). Sun
2).Thermoscope
3) White and black
4). Can be carried out in full vacuum
5). There is visible and invisible
6). We do it too
7). One type of heat transfer
answer: radiation
6.1).Energy
2). Heat transfer
3). Calorimeter
4). Weight dependent
5). Depends on body temperature difference
6). Depends on the type of substance
7). Measured in joules
7.1).One of two ways
2). Occurs at any temperature
3). The larger the surface of the liquid, the greater its speed
4). In the Finnish and Russian baths, it occurs at different speeds.
5). Its speed depends on the type of liquid
6) It happens faster the higher the temperature
7) Liquid vapor
answer: evaporation
8.1).Bubbles
2). Archimedean force
3). whistling kettle
4). One of two ways
5). Occurs at a certain temperature
6). 100 WITH
7). When this happens, the temperature of the liquid does not change.
answer: boiling
9.1).Gas operation
2). Fuel energy mechanical energy
3). XVII
4). James Watt
5). Dead point
6). It can be four-stroke
7). Has efficiency
Answer: heat engine
Magnetic phenomena
10.1). Hans Christian Oersted
2). A special kind of matter
3). Its source is a moving charge
4). Can be detected with iron filings
5). Has lines of force
6). It can be strengthened and weakened
7). The earth has it
Answer: magnetic field
11.1). North and South
2). Coil
3). Core
4). Telephone
5). Its effect can be strengthened or weakened
6). It can change poles
7). You can easily make it yourself
answer: electromagnet
12.1). It uses the property of a magnetic field to act on a conductor with current
2). Anchor
3). stator
4). 1834
5). Boris Semyonovich Jacobi
6). High efficiency
7). Widely used in transportation
answer: electric motor
light phenomena
13.1). "Sunny Bunny"
2). "Flying Dutchman"
3). Periscope
4). Reflection angle
5). The interface between two media
6). Reversibility of light rays
7). The angle of incidence is equal to the angle of reflection
Answer: law of reflection
14.1). It takes place at the border
2). Light changes direction
3). In fact, the stars are closer to us
4). It happens according to the law.
5). It can be controlled with a prism
6). Fishermen need to take into account
7). If it does not occur, then the reflection is complete
answer: refraction
15.1). With it, you can control the light beams
2). They are in our eyes
3). They are convex and concave
4). They have tricks
5). They scatter and gather
6). They are characterized by optical powerDocument
Geography for course 6 class « Physical geography" Teachers the highest category... Northeast America. Geographical dictation 1. Name the branches of modern geography. ... multi-year weather regime C) weather D) type weather 7. The thickness of the bottom layer...
Grade 10 Type of lesson
LessonFields. The principle of superposition of fields» Class: 10 Type lesson: learning new ... survey on previously studied material ( physicaldictation) Asks the question: “How is it carried out ... in writing to questions Remember course 8 class and answer: “Through the electric ...
The working program of the training course physical culture grade 1 was developed
Working programmM. : Education, 1998. - 112 p. Physical culture. 1-11 classes: comprehensive program physical education of students V.I. Lyakh ... dictation 1 Examination 54-56. Connection of words in a sentence 3 Combined Know: types offers...
Based on the requirements of the Federal State Educational Standard, where special attention is paid to the acquisition by students of experience in design and educational and research activities, I propose the development of a project on the topic: "Optical phenomena".
When working on this project, students form a meta-subject aspect of activity; which allows students to formulate the purpose of the work, define tasks and predict the result of their activities. The work on this project is aimed at solving an interesting problem related to optical phenomena, is of a practical nature and makes it possible to publicly show the achieved result.
Depending on the characteristics of the class, this project can be expanded to a large research work or, conversely, reduced to the boundaries of a specific topic of the 8th grade. Class students are invited to enter one of 4 groups: a) researchers public opinion; b) theorists; c) experimenters; each group gets its own task. Collects material with the help and on the recommendation of the teacher. Presents a report in the form of a presentation, practical work and demonstration experiment.
Depending on which class 8, 9 or 11 this project will be implemented in, the material can be expanded or reduced; whether the project will come out to a conference about what light is or will it be limited only to the scope of the lesson, all this depends on the temporary possibilities and desires of the teacher and students. Variations on this topic a lot of. This is one of the possible options.
The educational project is independent decision students or a group of students of any problem and a public presentation of the results of this work. This project is an information and research project with elements of practical orientation. New activities of students - independent search for information, analysis of this information, selection of the necessary information, use various kinds information.
Design, manufacture, creation, selection of an experiment and experimental equipment, information exchange, the ability to express one's point of view, develop it, defend it in a dispute.
Goals: Find out what role light plays in our lives. How a person received knowledge about light phenomena, what is the nature of light
Tasks: To trace the experience of mankind in the study and use of light phenomena, to find out the patterns and development of views on the nature of light; conduct experiments confirming these patterns; think over and create demonstration experiments proving the laws of light propagation in different optical media (reflection, refraction, dispersion, diffraction, interference).
Report of a group of public opinion researchers.
Goals: Show what role light phenomena play in our life; answer the question: “What do we know about this phenomenon?”.
The group studied proverbs, sayings, riddles related to light phenomena.
- "In the dark, even rotten things glow." (Russian)
- "Shadow high mountain- falls far. (Korean)
- "The tail follows the body, the shadow follows the object." (Mongolian)
- "The sun is brighter - the shadow is darker." (Tamil)
- "You can't run away from your shadow." (Udmurdskaya).
- “A good flower is in the mirror, but you won’t take it, the Moon is close, but you won’t get it.” (Japanese)
- "It's darkest before dawn." (English)
Puzzles:
For example:
- Why not hide in a box? (Light)
- You have it, I have it, the oak has it in the field, the fish has it in the sea. (Shadow).
- In the morning with a fathom, at noon with a span, and in the evening there is enough across the field. (Shadow)
- What can you not lift from the Earth? (Shadow and roads).
- From the window to the window, the spindle is ready. (Sunbeam).
Proverbs and sayings:
- The sun shines, but the moon only shines. (Russian).
- The colors of the rainbow are beautiful, but they are not durable, the color of pine and cypress is not very beautiful, but they are evergreen. (Chinese).
- Dress up by looking in the mirror, improve by looking at people. (Mongolian).
- You can't make white out of black. (Russian)
- The firefly does not glow in the sun. (Tamil)
The group conducted a small sociological survey
- What do you know about light phenomena?
- Why do people use glasses or lenses?
- What is the relationship between our vision and the information we receive from the outside world?
- How is the light from a fire different from the light of a fluorescent lamp?
Report of a group of theorists.
Goals: To study the laws of light propagation in a homogeneous and inhomogeneous transparent medium; behavior of a beam of light at the interface between two media. Wake cognitive interest, develop research skills: independently search, collect information, observe, analyze, be able to draw conclusions; be able to argue. “Can we see a beam of light? What is light?
Life on Earth arose and exists thanks to the radiant energy of sunlight.
The fire of a primitive man, the oil burning in the engines of cars, the fuel of space rockets - all this is light energy, once stored by plants and animals. Stop the solar stream, and rains of liquid nitrogen and oxygen will fall on the Earth. The temperature will approach absolute zero.
But not only energy is brought to the Earth by light. Thanks to the light flux, we perceive and cognize the world. Rays of light inform us about the position of close and distant objects, about their shape and color.
Light, amplified by optical devices, opens up to a person two polar worlds in terms of scale: space world with its vast expanses and microscopic, inhabited by the smallest organisms that are not visible to the naked eye.
Light allows us to perceive the world around us with the help of vision. Scientists have calculated that about 90% of information about the world around a person receives with the help of light through vision.
The brightest and most beautiful natural phenomena that a person gets acquainted with in his life are light. Remember the sunrises and sunsets, the appearance of a rainbow, the blue color of the sky, the glare of sunbeams, the iridescent color of soap bubbles, and how mysterious and deceptive mirages are!
Man has learned to use light in his various activities. Optical instruments installed on board aircraft or space station, make it possible to detect oil spills on the sea surface. The laser beam in the hands of the surgeon becomes a light scalpel suitable for complex operations on the retina. This same beam steel plant cuts massive sheets of metal, and cuts fabrics in the clothing industry. The light beam transmits messages, controls chemical reactions and is used in many other technological processes.
Have you thought about these questions:
Why are some objects colored and others white or black?
Why do bodies get hot when sunlight hits them?
Why is the shadow of the feet on the ground from the lantern sharply limited, while the shadow of the head is more blurry?
- Light is radiation that is perceived by the eye. This radiation is called visible.
- The radiation energy is partially absorbed by the bodies, as a result of which they heat up.
- The bodies from which light emanates are sources of light.
Based on the results of studying this topic, presentations were made on one of the proposed topics:
- Light sources (traditional and alternative).
- From the history of light sources.
- The sun and its influence on life on Earth.
- Solar and Lunar eclipses.
- Optical illusions and mirages.
- Mirrors in human life.
- Camera and projection equipment yesterday and today.
- What is optical fiber?
- The eye is a living optical instrument.
- How do animals see?
- Telescopes and their history. Observations of the Moon and planets.
- Microscope.
Conclusions: Light is only visible when it enters our eyes.
The light coming from various objects, entering the eyes of a person, produces an action, which is then processed by the brain, and we say what we see.
Different bodies reflect, transmit and absorb light in different ways.
Depending on which phenomenon plays the main role, we divide bodies into transparent and opaque.
Physical models:
If the dimensions of the luminous body are much smaller than the distance at which we evaluate its action, then the luminous body is called a point source.
A light beam is a line along which energy travels from a light source.
Light from a source can travel in a vacuum, air, or other transparent medium.
A medium is called homogeneous if it physical properties V different points have no differences or these differences are so insignificant that they can be neglected.
The law of rectilinear propagation of light:
In a homogeneous transparent medium, light propagates in a straight line.
The formation of a shadow is a consequence of the rectilinear propagation of light.
Vision Mechanism:
Reports of a group of experimenters.
Target: find out the dependence of the size of the shadow on the size of objects and on the distances between the source, the object and the screen; how a ray of light passes through the boundaries of different media; the behavior of the beam when it falls on a trihedral prism; how the angle of refraction changes with the angle of incidence.
Topics of experimental work:
- Obtain an image of a distant object (such as a window) on the screen through a pinhole in cardboard. Hole dimensions are about 5 mm.
- Propagation of light in a homogeneous transparent medium: air, water, glass.
- The formation of shadows behind objects from one and two light sources.
- What happens at the interface between two media: air-glass (opaque, transparent); air-water; air-mirror; air-sheets of paper (white, color, black)
- How does the angle of reflection change with a change in the angle of incidence at the air-mirror (water) boundary
- What happens to a ray of light when it falls on a trihedral prism; plane-parallel plate; round flask with water (without water)?
- How does the angle of refraction change when the angle of incidence changes when passing from air to water, to glass?
- How does the angle of refraction change when the angle of incidence changes when a beam of light passes from water to air; from glass to air
For laboratory work used a set of optics L-micro, Computer, multimedia projector.
Design team report.
Goals: Create demonstration experiments; explain the results of the observed phenomena. To cultivate accuracy when performing an experiment, observe safety precautions, responsibility, perseverance, and be able to analyze the result.
Experiments in geometric optics.
After studying the literature, several experiments were selected, which they decided to carry out themselves. They came up with experiments, made devices and tried to explain the results of the experiments.
Equipment: a jar of sour cream, black paint, tracing paper or thin paper, an elastic band and a small candle.
Make a small hole in the bottom of the jar, and use tracing paper instead of a lid, securing it with an elastic band. Light a candle and point the bottom of the jar at the candle flame. An image of a candle flame will appear on the tracing paper.
Tracing paper is an analogue of our retina. On it, the image of a candle is upside down. We also see the world upside down, but our brain processes the image of the eyes and flips it to make it easier for us to perceive information.
Equipment: flashlight, small mirror, foil, small object.
Wrap the end of the flashlight with foil, make a small hole in the foil and direct the flashlight beam at the mirror. A beam of light will bounce off the mirror and hit the object. We check the laws of reflection of light.
Equipment: stick a small mirror on a white piece of paper, a flashlight.
The mirror in this experiment looks like a black rectangle. Why?
Equipment: glass, two identical candles, matches.
Set candles to the same distance from glass from different sides. Light one of the candles. Move the candle so that the flame of the burning candle coincides with the wick of the unlit candle. The light from the flame of a burning candle reflects off the glass. The illusion of burning both candles is created.
Equipment: a transparent container, a flashlight, some milk, water, a screen.
Direct the flashlight beam at the water, the light will come out from the other side of the tank. If you shine a flashlight at an angle, pointing the beam slightly up. After passing through the water, the beam will be at the bottom of the vessel wall. If you add milk to water, the light will be better visible. The surface of the water acts like a mirror.
Literature:
- Textbook "Physics-9" ed. G.N. Stepanova.
- "Light" auth. IN AND. Kuznetsov - Moscow: "Pedagogy", 1977.
- "Physics in proverbs and sayings" S.A. Tikhomirova - Moscow: Interpraks, 1994.
- "Do you know physics?" ME AND. Perelman - Kvant Library Issue 82, 1992.
- « Big Book scientific experiments for children and adults” M. Yakovleva, S. Bolushevsky. - Moscow: Eksmo, 2013.
- « Project activity students. Physics grades 9-11. ON THE. Lymareva. - Volgograd: Teacher, 2008.
