Optical phenomena project. Lenses are transparent bodies bounded on both sides by spherical surfaces Experiments in geometric optics
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. Light spread
Light is radiation, but only that part of it that is perceived by the eye. In this regard, light is called visible radiation.
The bodies from which light emanates are sources of light.
Light sources are classified into natural and artificial.
Natural light sources- this is the Sun, stars, atmospheric discharges, as well as luminous objects of the animal and plant world.
Artificial light sources, depending on what process is the basis for obtaining radiation, are divided into thermal and luminescent.
TO thermal include electric bulbs, gas burner flames, candles, etc.
Luminescentsources are fluorescent and gas-light lamps
All light sources are sized. When studying light phenomena, we will use the concept of a point light source.
If the dimensions of the luminous body are much less 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 from a light source travels.
§ 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, passing from one constellation to another, and completes a full revolution during the year.
The Earth is one of the planets of the solar system. It revolves around the Sun in an elliptical orbit and revolves around its own axis. The movement of the Earth around the Sun and some tilt of the Earth's axis lead to a change in the seasons. When the Earth moves around the Sun, the Earth's axis remains parallel to itself.
Moon- the satellite of the Earth, the celestial body closest to the Earth. 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, shifts in the opposite direction and after another stop again changes the direction of movement to the original.
§ 65. Reflection of light. Light reflection law
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 we send 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 we 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 gets into our eyes, that is, it becomes visible.
Figure: 134. The incidence of rays of light on the screen
If you dust the air between the screen and the light source, then the entire beam of light becomes visible (Fig. 134, b). The dust particles reflect light and direct it into the eyes of the observer.
This phenomenon is often observed when the sun's rays penetrate the dusty air of a 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 specular surface.
Figure: 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 SO ray. The direction of the reflected beam is shown by the OB beam. SO beam - incident ray, beam OF - reflected beam... From the point of incidence of the ray O, the perpendicular OS is drawn to the surface MN. The SOC angle formed by the incident SO beam and the perpendicular is called the angle of incidence (α). The angle of the OWS formed by the same perpendicular OS and the reflected beam is called angle of reflection (β).
Thus, the reflection of light occurs according to the following law: the incident and reflected rays lie in the same plane with the perpendicular drawn to the interface between the two media at the point of incidence of the ray.
The angle of incidence α is equal to the angle of reflection β.
∠ α = ∠ β.
Any non-specular, that is, rough, nonsmooth, surface scatters light, since there are small protrusions and depressions on it.
§ 66. Plane mirror
Flat mirror is called a flat surface that reflects light. The image of an object in a flat mirror is formed behind the mirror, that is, where the object is not in reality.
Let diverging rays SO, SO 1, S0 2 fall on the mirror MN from a point light source S (Fig. 139).
According to the law of reflection, the SO beam is reflected from the mirror at an angle of 0 °; ray S0 1 - at an angle β 1 \u003d α 1; ray S0 2 is reflected at an angle β 2 \u003d α 2. A diverging beam of light enters the eye. If we continue the reflected rays behind the mirror, they will converge at 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 point S.
Figure: 139. Image of an object in a flat mirror
S 1 O \u003d 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. The law of refraction of light
A medium in which the speed of light propagation is slower is an optically denser medium.
In this way, the optical density of the medium is characterized by different speed of light propagation.
This means that the speed of light propagation is greater in an optically less dense medium. When a light beam hits a surface that separates two transparent media with different optical densities, for example, air and water, then 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, the light beam changes direction at the border of the media (Fig. 144). This phenomenon is called refraction of light.
Figure: 144. Refraction of light when the beam passes from air to water
Let's consider the refraction of light in more detail. Figure 145 shows: incident ray JSC, refracted beam ОВ and the perpendicular to the interface between the two media, drawn to the point of incidence O. Angle AOS - incidence angle (α), angle DOB - angle of refraction (γ).
A ray of light, when passing from air to water, changes its direction, approaching the perpendicular CD.
Water is optically denser than air. If water is replaced by some other transparent medium, optically denser than air, then the refracted ray 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 compose 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, you can write:
where n is a constant independent of the angle of incidence. It is called refractive index for two environments. The higher the refractive index, the more the ray 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 perpendicular drawn to the interface between the two media at the point of incidence of the ray 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.
Figure: 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 bounding the lens is called optical axis.
Figure: 152. Optical axis of the lens
By directing a beam of rays parallel to the optical axis of the lens at 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 focus lens.
Each lens has two focuses - one on each side of the lens.
Figure: 153. Collecting lens:
a - the passage of rays through the focus; b - its image on the diagrams
The distance from the lens to its focus is called focal length of the lens and is designated by the letter F.
A convex lens collects rays from a source. Therefore, a convex lens is called collecting.
This lens is called scattering.
Figure: 154. Diffusion 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 higher magnification; the optical power of such a lens is higher.
Lenses are characterized by a quantity called the optical power of the lens.... Optical power is indicated by the letter D.
The power of a lens is the reciprocal of its focal length..
The optical power of the lens is calculated by the formula
Diopter (diopter) is taken as a unit of optical power.
1 diopter is the optical power of a lens with a focal length of 1 m.
Section 69. Images given by the lens
With the help of lenses, you can not only collect or scatter rays of light, but also get 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 subject 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 dual focus, i.e.
F< f < 2F.
Thus, the size and position of the image of the object in the collecting lens depends on the position of the object relative to the lens.
§ 70. Eye and sight
The human eye has an almost spherical shape, it is protected by a dense membrane called the sclera. The anterior part of the sclera - cornea 1 is transparent. Behind the cornea (cornea) is the iris 2, which may vary from person to person. There is a watery liquid between the cornea and the iris.
Figure: 163. Human Eye
There is a hole in the iris - pupil 3, the diameter of which, depending on the illumination, can vary from about 2 to 8 mm. It changes because the iris is able to expand. Behind the pupil there is a transparent body, similar in shape to a collecting lens - this is the lens 4, it is surrounded by muscles 5 that attach it to the sclera.
The vitreous body 6 is located behind the lens. It is transparent and fills the rest of the eye. The posterior part of the sclera - the fundus - is covered with a reticular membrane 7 (retina). The retina consists of the finest fibers that, like villi, line the fundus. They are branched endings of the optic nerve that are sensitive to light.
Light falling into the eye is refracted on the front 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 in question is formed on the retina (Fig. 164).
Figure: 164. Formation of an image on the retina
Light falling on the endings of the optic nerve that make up the retina irritates these endings. Irritations are transmitted through nerve fibers to the brain, and a person gets a visual impression, sees objects. The vision process is corrected by the brain, so we perceive the object as direct.
And how is a clear image created on the retina when we look 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 therefore the optical power, increase.
The control work (test) in physics for intermediate certification for the academic year contains:
- Answer form (filled on both sides). Criteria for evaluation. Answers. Solutions to the tasks of part 3. Job options (1,2,3). Sample of a brief analysis of test papers.
Test
in physics (test)
for interim certification
for the academic year
student (s) 8 "" class
_____________________________
Answer form.
Part 1.
Job number
Part 2.
16.
AND
17.
AND
Part 3.
18.
Criteria for evaluation.
The final work consists of three parts.
Part 1 consists of 15 test items.
For each of 1-15 tasks, 4 answer options are given, of which only one is correct.
Each assignment 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 estimated at two points, if it is completed completely, one point is given if one incorrect answer is given.
Part 3 consists of one task.
When completing task 18, it is necessary to correctly solve and formalize the problem.
Task 18 is estimated at three points if the task is completely solved. Two points are given if the problem is correct, but the complete answer is not given (the calculations are not completed, there is no answer). One point is given if the problem is correctly formulated and the calculation formulas are correctly written.
Scale for transferring points.
The maximum number of points is 22 points.
Mark by
five-point scale
Criteria for evaluation. Grading for work performed. Rating "2" is given if the student scored less than 6 points for the entire work.Rating "3" is put in the event that the student scored from 6-10 points.Rating "4" is put in the event that the student scored from 11-15 points, provided that one task from part 2 has been completed correctly.Rating "5" is put in the event that the student scored from 16-22 points, provided that all the tasks of part 2 were correctly completed, or one task of part 2 and the task of part 3 (in whole or in part) were completed.
Answers. Part 1.
Job number
Part 2.Job number
Part 3. Option 1. Using the formula for determining the resistance of the conductor, the power of the current, Ohm's law for the section of the circuit and the tabular values, we get:P \u003d UI or P \u003d U 2 / R from here we find resistance: R \u003d U 2 / P , substitute in the formula for calculating the length of the conductor: L= U 2 S/ pPWe substitute the data:L \u003d 200V * 200V * 0.5mm 2 / 0.4 * 360W \u003d 138.9m ANSWER: 138.9m Option 2. Using the rules for connecting conductors and Ohm's law for the circuit section:U 1 \u003d U 2 \u003d U, I \u003d U / R Determine the current strength in each section of the circuit:I 1 \u003d U / R 1 I 2 \u003d U / R 2 Let's find the current ratio:I 2 / I 1 \u003d UR1 / UR2 or I2 / I1 = R1 / R2 Let's substitute the data:I2 / I1 \u003d 150/30 \u003d 5 times ANSWER: the current 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 \u003d U / I Find the cross-sectional area:S= pLI/ ULet's substitute the data:S \u003d 1.1 * 5 * 2/14 \u003d 0.79 mm 2 ANSWER: 0.79mm 2
Option 1. Part 1.
1.During processing on the machine, the part is heated. What happened to her inner energy?
1) unchanged 2) increased as a result of heat transfer 3) increased due to the performance of work 4) decreased due to heat transfer
2. What kind of heat transfer is accompanied by the transfer of matter?
1) thermal conductivity 2) convection 3) radiation 4) thermal conductivity and radiation
3. When a substance passes from a liquid to a solid state
1) the forces of attraction between the particles increase 2) the potential energy of 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 2100J / kg about FROM . How the internal energy of 1kg of ice changed when cooled by 1 about FROM?
1) increased by 2100 J 2) decreased by 2100 J 3) did not change 4) decreased by 4200 J
5. Internal energy of an evaporating liquid
1) does not change 2) decreases 3) increases 4) depends on the type of fluid
6.Around stationary electric charges there is
1) electric field 2) magnetic field 3) electric and magnetic field 4) gravitational field
7. The atom has 5 electrons, and the nucleus of this atom has 6 neutrons. How many particles are there in the nucleus of this atom?
1)5 2)6 3)11 4)16
8. What particles move to create electric current in metals?
1) electrons 2) protons 3) ions 4) neutrons
9. What is the current in an electric lamp with a resistance of 10 ohms with a voltage at its ends of 4V?
1) 40 A 2) 2.5 A 3) 0.4 A 4) 0.04 A
10. The 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 coil with current can be increased 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 size of a luminous body is much less than the distance at which its action is estimated, then it is called
1) artificial 2) luminescent 3) spot 4) ideal
13. The 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 an object 2) real, equal to an object 3) real, any size 4) imaginary, 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 different media 4) light travels very slowly
Part 2.
16. Establish a correspondence between physical quantities and formulas for their calculation.
PHYSICAL QUANTITIES
AND
17. Set the 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 3.18. How many meters of nickel wire with a cross section of 0.5 mm 2 is required for the manufacture of a 360W heating element designed for a voltage of 200V?
Final test in physics, grade 8. Option 2. Part 1.
For each of tasks 1-15, 4 answer options are given, of which only one is correct. Indicate it.
1. Water was heated in a vessel. What can you say about her internal energy?
1) the internal energy has not changed 2) the internal energy has decreased 3) the 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 allowing 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 there is air in the pores that has poor thermal conductivity
3. Hot and cold water was 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 of cold water has decreased 3) how much the internal energy of hot water has decreased, the internal energy of cold water has increased by the same amount 4) the internal energy of hot water has decreased more than it has increased internal energy of cold water
4. When burning fuel with a mass m the amount of heat is released Q ... The specific heat of combustion of the fuel can be calculated by the formula
1) Qm 2) Qt / m 3) Q / mt 4) Q / m
5. For which type of vaporization - evaporation or boiling - an external energy source is needed?
1) evaporation 2) boiling 3) boiling in a closed vessel 4) boiling and evaporation
6.Ebony stick rubbed on wool. What about the charges acquired by the stick and the wool?
1) both positive 2) stick - positive, wool - negative 3) both negative 4) stick - negative, wool - positive
7. Electric current in metals is an orderly movement
1) electrons 2) protons 3) ions 4) charged particles
8. A source of electric current is required for
1) creating an electric current 2) creating an 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, 6 of them 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 current coil have?
1) none 2) one-north 3) one-south 4) two-north and south
12. The light beam is the line
1) along which the light moves 2) along which the energy from the source propagates 3) along which the 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 subject to plane mirror and distance from mirror to image
1) equal 2) 2 times more 3) 2 times less 4) 4 times different
15. On the basis of what law can be explained the "break" of a spoon, dipped in a glass of water, on the border of air - water?
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 strength and how many times?
Final test in physics, grade 8. Option 3. Part 1.For each of tasks 1-15, 4 answer options are given, of which only one is correct. Indicate it.
1.The steel ruler is hit with a hammer. In what way does the internal energy of the ruler change?
1) heat transfer 2) performance of work 3) heat transfer and performance of 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) thermal conductivity and convection 2) thermal conductivity and radiation 3) convection and radiation 4) thermal conductivity, convection and radiation
4. Copper melts. How does her internal energy change?
1) increases 2) decreases 3) does not change 4) becomes equal to zero
5. How will the rate of evaporation of a liquid change with increasing temperature?
1) increases 2) decreases 3) does not change 4) cannot be said for sure
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 positive 4) they may not have charges
7. In the nucleus of an atom there are 5 protons and 6 neutrons. How many electrons are there in this atom?
1)1 2)5 3)6 4)11
8. Electric current is called
1) random movement of particles of matter 2) directional movement of particles of matter 3) directional movement of charged particles 4) directional movement of electrons
9. What is the formula for calculating the voltage at the ends of the conductor?
1) I \u003d U / R 2) U \u003d IR 3) P \u003d IU 4) A \u003d P / t
10. The deflection of a magnetic needle located near a conductor with a current 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 light propagation 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 light source is located at a distance of 10 cm from the flat mirror. How far from the mirror is his image?
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 examinations in physics (test) for intermediate certification for the academic year. Class : 8 a, b, c.amount : students.Overall academic performance : % High-quality academic performance : % Grades for work :
"five"
Completely correctly completed the work ________, scored 22 points out of 22 possible.____________ scored 21 points out of 22.Part 1 was completed by all students. Major mistakes in Part 1 (common):- Recognition of physical phenomena Definition of thermal processes. Determination of electrical quantities. Knowledge of Ohm's Law for a chain site. Determination of angles of incidence and reflection (the law of light reflection).
- Correspondence of formulas and units of measurement. On the correspondence of physical quantities and units of measurement.
Based on the requirements of the Federal State Educational Standard, where special attention is paid to the acquisition of experience in design and educational research activities by students, I propose the development of a project on the topic: "Optical phenomena".
When working on this project, students develop a meta-subject aspect of their 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 allows publicly showing 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 8th grade topic. Pupils of the class are invited to enter one of 4 groups: a) researchers of public opinion; b) theorists; c) experimenters; each group gets its own task. Collects material with the help and recommendation of the teacher. Provides a report in the form of a presentation, hands-on work and demo 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 go to a conference about what light is or will be limited only by the scope of the lesson, it all depends on the time capabilities and desires of the teacher and students. There are many variations on this topic. This is one of the possible options.
An educational project is an independent solution by 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 types of student activity - independent search for information, analysis of this information, selection of the necessary information, use of various types of information.
Design, manufacture, creation, selection of experiment and experimental equipment, exchange of information, the ability to express one's point of view, develop it, defend in a dispute.
Objectives: Find out what role light plays in our life. How did a person gain knowledge about light phenomena, what is the nature of light
Tasks:To trace the experience of mankind in the study, use of light phenomena, to find out the patterns and development of views on the nature of light; conduct experiments confirming these patterns; to think over and create demonstration experiments proving the laws of light propagation in different optical media (reflection, refraction, dispersion, diffraction, interference).
Opinion Research Group Report.
Objectives: 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, and the rotten glows." (Russian)
- "The shadow of a high mountain falls far away." (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." (Udmurd).
- "The flower in the mirror is good, but you can't take it, the moon is near, but you can't get it." (Japanese)
- "It's darkest before dawn." (English)
Puzzles:
For instance:
- What can't be hidden in the box? (Shine)
- You have, I have, by the oak - in the field, by the fish in the sea. (Shadow).
- A fathom in the morning, about a span at noon, and enough across the field in the evening. (Shadow)
- What can't you pick up from the Earth? (Shadow and Roads).
- From the window - the spindle is ready to the window. (Sunbeam).
Proverbs and sayings:
- The sun is shining, but the month is only shining. (Russian).
- The colors of the rainbow are beautiful, but it is not durable, the color of pine and cypress is not very beautiful, but they are evergreen. (Chinese).
- Dress up by looking in the mirror, correct yourself by looking at people. (Mongolian).
- You can't make white out of black. (Russian)
- The firefly does not shine 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 connection between our vision and the information that we receive from the outside world?
- What is the difference between campfire light and fluorescent lamp light?
Report of a group of theoreticians.
Objectives:Study the laws of light propagation in a homogeneous and inhomogeneous transparent medium; the behavior of a light beam at the interface between two media. Arouse cognitive interest, develop research skills: independently search, collect information, observe, analyze, be able to draw conclusions; be able to argue. - “Do we see a ray of light? What is light? "
Life on Earth originated and exists thanks to the radiant energy of sunlight.
The bonfire of primitive man, oil burning in the engines of cars, the fuel of space rockets - all this is the light energy once stored by plants and animals. Stop the flow of the sun, and the Earth will be rained from liquid nitrogen and oxygen. The temperature will approach absolute zero.
But not only energy brings light to the Earth. Thanks to the light flux, we perceive and cognize the world around us. The rays of light tell us about the position of close and distant objects, about their shape and color.
Light, amplified by optical devices, reveals to man two worlds that are polar in scale: the cosmic world with its enormous dimensions and the microscopic one, inhabited by the smallest organisms that are indistinguishable to the simple eye.
Light allows us to know the world around us with the help of sight. Scientists have calculated that about 90% of information about the world around a person receives with the help of light through sight.
The brightest and most beautiful natural phenomena with which a person gets acquainted 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 deceiving mirages are!
Man has learned to use light in his various activities. Optical instruments on board an aircraft or space station can 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. The same beam cuts massive sheets of metal at a metallurgical plant, and cuts fabrics at a garment factory. The light beam conveys messages, controls chemical reactions, and is used in many more technological processes.
Have you ever thought about such questions:
Why are some objects colored and others white or black?
Why do bodies heat up when sunlight hits them?
Why is the shadow of the feet on the ground from the lantern sharply limited, and the shadow of the head more vague?
- 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 Fiber Optic?
- The eye is a living optical device.
- How do animals see?
- Telescopes and their history. Observations of the Moon and planets.
- Microscope.
Conclusions: Light is visible only when it hits our eyes.
Light emanating from different objects, falling into the eyes of a person, produces an action, which is then processed by the brain, and we say that we see.
Different bodies reflect, transmit, and absorb light in different ways.
Depending on what phenomenon plays the main role, we divide bodies into transparent and opaque.
Physical models:
If the dimensions of the luminous body are much less 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 from a light source travels.
Light from a source can travel through vacuum, air, or other transparent medium.
A medium is called homogeneous if its physical properties at different points do not differ or these differences are so insignificant that they can be neglected.
The law of rectilinear light propagation:
In a homogeneous transparent medium, light propagates in a straight line.
Shadow formation is a consequence of rectilinear light propagation.
Vision mechanism:
Experimental group reports.
Goal: find out the dependence of the size of the shadow on the size of objects and on the distance between the source, object and screen; how a ray of light passes through the boundaries of different media; the behavior of the beam when it falls on a triangular prism; how the angle of refraction changes when the angle of incidence changes.
Experimental topics:
- Get an image of a distant object (for example, a window) on the screen through a pinhole in the cardboard. Hole dimensions are about 5 mm.
- Light propagation in a homogeneous transparent medium: air, water, glass.
- 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-paper sheets (white, colored, black)
- How the angle of reflection changes when the angle of incidence changes at the air-mirror (water) interface
- What happens to a ray of light when it hits a triangular prism; plane-parallel plate; a round flask with water (no water)?
- How does the angle of refraction change when the angle of incidence changes when going from air to water, to glass?
- How the angle of refraction changes when the angle of incidence changes when the light beam passes from water to air; from glass to air?
For laboratory work, a set of L-micro optics, a computer, a multimedia projector is used.
Design team report.
Objectives:Create demo experiments; explain the results of the observed phenomena. To cultivate accuracy when performing an experiment, observe safety precautions, responsibility, perseverance, be able to analyze the result obtained.
Experiments in geometric optics.
Having studied the literature, several experiments were selected, which they decided to carry out themselves. They came up with experiments, made instruments and tried to explain the results of the experiments.
Equipment: a jar of sour cream, black paint, tracing paper or tissue paper, an elastic band and a small candle.
Make a small hole in the bottom of the jar, and use tracing paper instead of the lid, securing it with an elastic band. Light a candle and direct the bottom of the jar towards the candle flame. An image of a candle flame will appear on the tracing paper.
Calca is an analogue of our retina. On it the image of a candle is inverted. We also see the world upside down, but our brain processes the image of the eyes and turns it over 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 to the mirror. The beam of light will bounce off the mirror and hit the object. Checking the laws of light reflection.
Equipment: stick a small mirror on a white piece of paper, flashlight.
The mirror in this experiment looks like a black rectangle. Why?
Equipment: glass, two identical candles, matches.
Install candles at the same distance from the glass on 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 is reflected from the glass. The illusion of burning both candles is created.
Equipment: transparent container, flashlight, some milk, water, screen.
Direct the flashlight beam at the water, the light will come out from the other side of the container. If you shine a flashlight at an angle, directing the beam slightly upward. After passing through the water, the beam will be at the bottom of the vessel wall. If you add milk to the water, the light will be better seen. The surface of the water works like a mirror.
Literature:
- Textbook "Physics-9" ed. G.N. Stepanov.
- "Light" auth. IN AND. Kuznetsov - Moscow: "Pedagogy", 1977.
- "Physics in Proverbs and Sayings" S.А. Tikhomirova - Moscow: Interprax, 1994.
- "Do you know physics?" ME AND. Perelman - Kvant library, issue 82, 1992.
- "Big Book of Scientific Experiments for Children and Adults" M. Yakovleva, S. Bolushevsky. - Moscow: Eksmo, 2013.
- “Project activities of students. Physics grades 9-11. ON. Lymareva. - Volgograd: Teacher, 2008.
Nikolskaya secondary school
Composed by: physics and computer science teacher
Nikolskaya secondary school
Spassky district
Republic of Tatarstan
V.P. Avdonina
8th grade
Physical dictations of type 1.
Select from the listed concepts the units of measurement, physical quantities, devices, phenomena, processes. The answer is presented in the form of a table:
units | physical quantities | devices | processes |
joule, energy, free fall, diffusion, velocity, temperature, С, m / s, potential energy, deformation, internal energy;
heat transfer, calorie, thermometer, beaker, calorimeter, convection, kg, heat capacity, mass, J / kg, С, 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 humidity, hair hygrometer, С, temperature,%, evaporation, condensation;
current strength,R, ampere, milliammeter, electric voltage, voltmeter, Ohm, rheostat, resistivity, m, mm 2 , cross-sectional area;
work of electric current, joule. Watt, power of electric current, 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. The answer is presented in the form of a table:
thermal and electrical phenomena
electrification, 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, work of electric current, 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
Insert missing words or complete a sentence.
Theme: Internal energy.
A molecule is the smallest particle ... ... (substance)
there are two types of mechanical energy that atoms possess:… .. (kinetic and potential).
The energy of motion and interaction of particles that make up the body is called…. (internal energy)
Internal energy of the body…. from its mechanical energy. (does not depend).
When the body temperature 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…. (doing work on the body).
Among metals ... (silver, gold) have the highest thermal conductivity.
Porous bodies have poor thermal conductivity, as they contain ... (air).
Heat transfer in vacuum by means of thermal conduction ... (not possible).
Convection occurs in solids, ... (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 the radiation incident on them. (OK)
For convection to take place in water, it must be cooled ... or heated ... (top, bottom).
Theme: Thermal phenomena
The energy that the body receives or loses during heat transfer is called ... (amount of heat).
The unit of the amount of heat is called ... (joule).
The specific heat capacity of water is ... (4200 J / kg FROM).
Specific heat capacity of the same substance in different states of aggregation ... (different).
Melting is the transition of a substance ... (from a solid state to a liquid).
The amount of heat released during 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 ice mass at 0 S. (more)
When ice melts, its temperature ... (does not change).
The crystallization process is accompanied by ... heat. (highlighting)
The formula for the amount of heat required to melt a substance ... (Q \u003d m)
Amorphous bodies include, for example ... (glass, rosin, candy)
Amorphous bodies ... of a certain melting point. (Dont Have)
The reverse process of vaporization is called ... (condensation)
Dew formation. The clouds are associated with thermal phenomena such as ... (condensation)
Condensation is accompanied by ... energy. (highlighting)
The amount of heat required to turn 1 kg of liquid at 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 a given substance ... (the same)
Theme: Electrical phenomena.
Electron is translated from Greek as ... (amber)
The charge separation process is called ... (electrification)
There are two types of charges: ... (positive and negative)
Charges of the same name ..., and unlike charges ... (repel, attract)
The electric charge is divided into ... parts. (equal)
One way to electrify is ... (friction)
The device for measuring electric charge is called ... (electrometer)
The minimum electric charge is ... (1.6 10 -19 Cl)
The atomic nucleus includes ... (protons and neutrons)
The idea of \u200b\u200ban atomic nucleus belongs to ... (E. Rutherford)
A special type of matter is formed around a charged body, which is called ... (electric field)
Electrification is used, for example ... (when painting the body of cars, when smoking.)
English physicists were engaged in the study of the interaction of electric charges: ... and ... (D. Maxwell and M. Faraday)
The unit for measuring electric charge is named after the French physicist ... (C.O. Coulomb)
Topic: Electric current. Current strength.
Topic: Electrical voltage.
Voltage is a physical quantity that characterizes ... that creates a current. (electric field)
The voltage shows ... when moving an electric charge equal to 1 C. (current work)
A value equal to the ratio of the work of the current in a given section to the electric charge passed through this section is called ... (voltage)
The unit of voltage is taken as ... (volt)
The voltage unit is named after an Italian scientist ... (A. Volta)
1 V \u003d ... (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 a switch on the device is called ... (parallel)
The current in the circuit is directly proportional to ... (voltage at the ends of the circuit)
Voltage is indicated by the letter of the Latin alphabet - ... (U)
Theme: Electrical resistance.
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 different ... (resistance)
The unit of resistance is taken as ... (Ohm)
The unit for measuring the electrical resistance of a conductor is named after a 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 strength of the current in a section of the circuit 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 constant ... (current strength in the conductor, voltage at the ends of the conductor)
Resistance of a conductor made of a given substance with a length of 1 m, a cross-sectional area of \u200b\u200b1 m 2 called ... (resistivity)
The device for regulating the current in the circuit is called ... (rheostat)
Topic: Parallel and serial 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 ... (sequential)
An example of a serial connection is the connection of ... (bulbs in a Christmas tree garland)
With a series connection, the current in any part 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 equal to ... (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 ... (lamps and sockets in the apartment)
Voltage at the section of the circuit and at the ends of all parallel-connected conductors…. (same)
The current in the unbranched part of the circuit is ... in separate parallel-connected conductors. (amount)
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. (amount)
Topic: Work and power of electric current.
To determine the work of an electric current in any section of the circuit, you need ... (the voltage at the ends of this section of the circuit is multiplied by the electric charge)
The work of the electric current in the section of the circuit is equal to ... (the product of the voltage at the ends of this section by the current strength and by the time during which the work was performed)
The power of the electric current is ... (the product of voltage and current)
Per unit of power taken .. (watt)
1 W \u003d ... (1 J/ from)
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 strength, the resistance of the conductor and time)
The lamp, convenient for industrial production with a carbon filament, was created by an American inventor…. (T. Edison)
The 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)
Purpose of fuses ... (immediately disconnect the line if the current is more than the permissible norm)
Fuses with a consumable conductor are called ... (fusible)
The device for measuring the work of electric current is called ... (counter)
Theme: Magnetic phenomena.
Interaction forces arise between conductors with current, which are called ... (magnetic)
The interaction of a conductor with a current and a magnetic needle was first discovered by a Danish scientist ... (Oersted)
There is ... (magnetic field) around a conductor with electric current
The source of the magnetic field is ... (moving charge)
The magnetic field around a conductor with a 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 field lines)
the magnetic lines of the magnetic field are ... curves that enclose the conductor. (closed)
A coil with an iron core inside is called ... (electromagnet)
The magnetic field of the coil with current can be increased if, ... (increase the current strength, increase the number of turns in the coil, insert the core)
Electromagnets are used, for example ... (in telephones, telegraph, magnetic relay)
Bodies that retain their magnetization for a long time are called ... (permanent magnets)
Every magnet must have ... (pole)
The like poles of a magnet ..., and unlike poles - ... (repel, attract)
The Earth has…. (a magnetic field)
The magnetic poles of the Earth ... with its geographic poles. (do not match)
One of the largest magnetic anomalies - ... (Kursk)
The compass was invented in ... (China)
The rotation of a coil with a current in a magnetic field is used in a device ... (electric motor)
One of the world's first electric motors suitable for practical use was invented by a Russian scientist ... (B.S. Jacobi)
Theme: Light phenomena.
Light is ... (visible radiation)
Light sources are divided into ... and ... (natural and artificial)
If the dimensions of the luminous body are much less than the distance at which we evaluate its action, then the luminous body is called ... (point source)
A light ray is a line ... (along which light travels)
A shadow is that area of \u200b\u200bspace ... (into which the light from the source does not fall)
Penumbra is that region of space ... (into which light from a part of the source enters)
When the Moon falls into the shadow of the Earth, then ... (lunar eclipse)
When the shadow of the moon falls on the Earth, in this place on Earth is observed ... (solar eclipse)
The angle between the incident ray and the perpendicular restored at the point of incidence of the ray to the interface between the two media is called ... (angle of incidence)
The angle of incidence is ... (angle of reflection)
The imaginary image of an object in a flat mirror is ... distance from the mirror, at which the object itself is. (on the same)
The 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)
The change in the direction of propagation of light 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)
Lenses are of two types: ... (convex and concave)
Lenses with edges that 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 the lens is called ... (optical power)
If aF< d<2 F, then the image will be ... (real, enlarged, inverted, located on the other side of the lens)
If ad>2 F, then the image will be ... (real, inverted, zoomed out, located on the other side of the lens)
If ad< F, then the image will be ... (imaginary, straight, 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)
A physical quantity, its designation, a unit of measurement, a device, a formula, a term associated with a physical quantity, etc. corresponds to a physical exercise that is suitable in meaning (the exercise can be performed while sitting)
power - arms bend at the elbows, showing their muscles ("strongmen")
time - they look at the hand, bending it at the elbow, imitating movement, when they look at the watch worn on the hand;
speed - imitate running;
length, path - arms 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, imitating the movement when lifting the bar;
density - show two exercises in a row related to mass and volume
pressure - rise in a chair on their hands
work - do two exercises in a row related to strength and path
energy - jumping in place
Children are happy to come up with such exercises themselves.
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
five). Degree Celsius
6). If it rises with us, we get sick.
7). It is measured with a thermometer
answer: temperature
2.1) .thermal motion
2) .molecules
3). Depends on the state of aggregation
4) deformation
five). 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 is bad and good for different substances
2). Vacuum
3). "Does the fur coat warm"
4). "Laughing like a sparrow"
five). Good for metals
6). The phenomenon of transfer of internal energy
answer: thermal conductivity
4.1). Phenomenon
2). Wind
3). It happens natural and free
4). Can't happen in solids
five). Needs to be heated from below
6). Energy is carried by jets of gas or liquid
7). Heat transfer type
answer: convection
5.1). The sun
2) .Thermoscope
3) White and black
4). Can be carried out in full vacuum
five). There are visible and invisible
6). We do it too
7). One of the types of heat transfer
answer: radiation
6.1) .Energy
2). Heat transfer
3). Calorimeter
4). Depends on the mass
five). Depends on the difference in body temperature
6). Depends on the type of substance
7). Measured in joules
7.1) One of two ways
2). Happens at any temperature
3). The larger the surface of the liquid, the greater its speed
4). In the Finnish and Russian baths, it happens at different speeds.
five). 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). Whistle kettle
4). One of two ways
five). Occurs at a certain temperature
6). 100 FROM
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
five). Dead point
6) .There is a 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 found with iron filings
five). Has ley lines
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). Phone
five). Its effect can be increased or decreased.
6). He can change the poles
7). You can easily do it yourself
answer: electromagnet
12.1). It uses the property of a magnetic field to act on a conductor with a current
2). Anchor
3). Stator
4). 1834 g.
five). Boris Semyonovich Jacobi
6). High efficiency
7). It is widely used in transport
answer: electric motor
Light phenomena
13.1). "Sunny Bunny"
2). "Flying Dutchman"
3). Periscope
4). Reflection angle
five). The interface between two media
6). Reversibility of light rays
7). The angle of incidence is equal to the angle of reflection
answer: the law of light reflection
14.1) It happens at the border
2). The light changes direction
3). In fact, the stars are closer to us
4). It happens according to the law
five). It can be controlled with a prism
6). It must be taken into account by fishermen
7). If it does not happen, then the reflection is complete.
answer: refraction
15.1). With it you can control light beams
2). We have them in our eyes
3). They are convex and concave.
4). They have magic tricks
five). They scatter and collect
6). They are characterized by optical powerDocument
Geography for course 6 class « Physical geography "Teachers of the highest category ... North-East America. Geographical dictation 1. Name the branches of modern geography. ... long-term weather mode C) weather D) type weather 7. The thickness of the bottom layer ...
Grade 10 Lesson type
LessonFields. The principle of superposition of fields " Class: 10 A type lesson: learning new ... a survey on previously learned material ( physicaldictation) Asks the question: “How is it done ... in writing to the questions Recall course 8 class and answer: “Through the electric ...
The working program of the physical education class 1 is developed
Working programmM.: Education, 1998 .-- 112 p. Physical culture. 1-11 classes: comprehensive program physical education of students of V. I. Lyakh ... dictation 1 Control work 54-56. Connection of words in sentence 3 Combined Know: types suggestions ...
