Light must enter our eyes in order for us to see something. If we close our eyes or enter a dark room, we will not see anything. We can perceive the visual world only with the help of our vision.
A light source is a body that emits light - the sun, lamp, candle, etc.
Our eye also perceives light from those bodies that are illuminated by some light source. All bodies are capable of reflecting light to a greater or lesser extent. 
Shadow
Light travels in a straight line. The light beam is visible especially well if there are dust particles or water droplets in the air that reflect the light.
If a ray of light falls on an opaque object, an unlit spot called a shadow appears behind it. Depending on the distance the object is from the light source, the size of the shadow may change. 
If we illuminate an object with two lamps that stand side by side, then two shadows appear, partially overlapping one another.
Places that are not illuminated by any source are called direct shadow. Unlike direct shadow, penumbra is formed by the overlap of shadow and light. 
The sun constantly illuminates the moon. Since the Moon makes a complete revolution around the Earth every 28 days, we can observe the degree of illumination of the Moon's surface over time. 
During the new moon, the Moon is between the Sun and the Earth in such a way that its illuminated part is not visible to us.
The moon is growing, and we see more and more of the illuminated part of the surface. During the full moon, we observe the fully illuminated surface of the Moon.
When the Moon wanes, the illuminated part visible from the Earth slowly disappears, until the Moon turns into a thin crescent.
Once every 1.5 years, the trajectory of the Moon intersects the trajectory of the Earth, so the Moon falls into the shadow cast by the Earth. 
It is then that the Moon is not illuminated by the Sun, and we do not see it. This is called a lunar eclipse. 
Approximately once every 2.5 years, the Moon is located between the Sun and the Earth. At this moment, a partial solar eclipse can be observed. If you are on Earth in a place where the Moon casts a shadow, the diameter of which is approximately 260 km, you can see a total eclipse of the Sun. But this phenomenon is very rare and occurs no more than once every 200 years. 
Short-term plan for conducting an open lesson in physics in 8"B" according to the program
Cambridge University physics teacher R.T. Kuspakova
Coming together is a beginning. Sticking together is progress. Working together is success.
Henry Ford.
It is not enough to have a good mind, the main thing is to use it correctly.
Rene Descartes.
04/16/16 Subject physics Class 8 “B”
Lesson topic:
Light. Light sources. Star - Sun. Law of rectilinear propagation of light. Shade and partial shade. Solar and Lunar eclipses.
Duysembaev B.M. and others. Physics and astronomy: Textbook for 8th grade. general education school, 2nd edition, revised/B.M. Duisembaev, G.Z. Baizhasarova, A.A. Mendetbekova. – Almaty; Publishing house "Mektep", 2008.-256 pp.; ill.
Goals:
Objective of the lesson:
familiarize students with natural and artificial light sources; explain the law of rectilinear propagation of light; explain the nature of solar and lunar eclipses.To encourage students to overcome difficulties in the process of mental activity, to cultivate interest in physics.
Learning outcomes:
Everyone knows what is light, shadow, penumbra, eclipse.Most can applyin practicebasic knowledge of light phenomena.Some are capable analyze the differences between the formation of shadow and penumbra, eclipses.Be able to describe physical phenomena based on knowledge. Be able to formulate complete and competent answers and questions.Learning new concepts, learning to work in a group, the ability to listen to opinions, ask questions on a topic.
Key ideas:
group mutual learning will allow students to get closer, teach them the ability to hear and listen to their interlocutor, be more tolerant of each other, increase educational and cognitive motivation, and improve the psychological climate in the class; the ability to conduct a dialogue will teach you to argue your point of view; activating students' critical thinking will allow them to solve problems posed to them, develop research skills, relying on their own and indirect experience, will increase the efficiency of assimilation and updating of knowledge, which will make it possible to transfer students into self-development mode.
Time
Strategies
Resources
Lesson content
Teacher's activities: what will I do?
Activity
students
Org.
moment. (2min)
Greetings, division into 2 groups(according to the inscription on candy wrappers),and presentation of the expert council
Greet
each other- Cross your arms over your chest (Arabs).
To create a collaborative environment, she uses the “Compliments” strategy.
Compliment the neighbor on your right, and thank the neighbor on your left for something.
Introductory part (10 min)
ICT,
group work,
KM,
ODO,
Internet resources.
Textbook
physics 8th grade,
physics reference book,posters,
cell phones.
Before starting to study a new topic, it is necessary to analyze the results of the test, answer questions that arise on the work, and analyze the most common mistakes.I . Learning new material Plan for presenting new material: 1. Light as visible radiation. 2.Natural and artificial light sources. 3.Beam and beam. 4.Law of rectilinear propagation of light. 5.Shade and partial shade. 6.Solar and Lunar eclipses. In a brief introductory conversation, I will tell students about the importance of light in human understanding of the world around us. Thanks to the organ of vision, a person sees the world around him, communicates with the environment, and can work and relax. Labor productivity depends on how objects are illuminated. Without sufficient lighting, plants cannot develop normally. Knowledge of the patterns of light phenomena makes it possible to design various optical devices that are widely used in human practice. The best illustration of the significance of light phenomena in human life is a “minute” experiment: invite students to close their eyes for one minute and imagine “life in darkness”!!! What is light? All bodies are made of atoms (or molecules). But just as there is no sound in a guitar string, there is no light in an atom. The state of the atom, when its energy is minimal, is called normal (or unexcited). In this state, the atom does not radiate energy. Any other state of an atom with an energy different from the minimum is calledexcited. An atom can remain in an excited state for 10 3 With. The transition of an atom from an excited state to a normal state is accompanied by the emission of electromagnetic waves.Light is electromagnetic radiation perceived by the eye through visual sensation. Question:-How does the radiation from an iron or boiler differ from the radiation from an incandescent electric lamp?Light source are bodies that are capable of emitting light. Every luminous body consists of a huge number of “elementary” emitters. Thus, the optical radiation of light sources is a set of radiation from individual atoms and molecules. " By demonstrating to students various sources of light (a burning match, a candle, a glowing light bulb), the teacher communicates that there arenatural Andartificial light sources. Natural light sources are the Sun, stars, atmospheric charges, as well as luminous objects of the animal and plant world (fireflies, rotten bugs, etc.) Artificial light sources, depending on what process underlies the production of radiation, are divided intothermal Andluminescent. - Give examples of natural and artificial light sources.Since light is electromagnetic radiation and has all the properties of electromagnetic waves, all problems in optics can be solved on the basis of wave concepts. However, this requires the use of a very cumbersome mathematical apparatus. However, when solving problems of constructing images in mirrors and lenses and when calculating optical instruments, scientists use geometric methods. These methods constitute the contentgeometric optics, which is otherwise calledradial optics. The basic concepts of geometric optics arebeam and beam. Moreover, these concepts cannot be identified. A beam of light can be observed, but the beam can only be drawn on paper: -cylindrical or conical channels within which light propagates are calledlight beams ; - beam called a geometric line indicating the direction of transfer of light energy. Now the differences between these physical concepts and such figurative and literary “analogs” as “rays of the Sun”, “a ray of light fell on the table”, “Katerina is a ray of light in a dark kingdom”, and so on are obvious. There are no infinitely narrow beams of light; a beam of light always has a finite width. The beam is like the axis of the beam, and not the beam itself.Geometric optics is based on three laws: a) the law of rectilinear propagation of light; b) the law of light reflection; c) the law of light refraction.Light propagates rectilinearly in a homogeneous medium - this is how the law of rectilinear propagation of light is formulated. What examples can you give to prove that light travels in a straight line?Optically homogeneous a medium in which light travels at a constant speed is considered. If there are two media in which light travels at different speeds, then the medium where light travels at a lower speed is calledoptically more dense, and the environment where light travels at a higher speed -optically less dense. Shade and partial shade. The straightness of light propagation is confirmed by the formationshadows. If you take a small light source, a screen, and place an opaque object between them, a dark image of its outline will appear on the screen - a shadow.A shadow is an area of space that does not receive light energy from a light source. - Why does the formation of a shadow serve as evidence of the linear propagation of light? In the experiment, we did not take into account the size of the light source. A light source whose dimensions are small compared to the distance to the screen is calledpoint light source. If we take a larger light source, then a penumbra will also form on the screen around the shadow.Penumbra is a region of space into which light energy from a light source partially enters. The formation of shadow and penumbra explains solar and lunar eclipses.During a solar eclipse The full shadow of the Moon falls on the Earth. The Sun is not visible from this place on Earth. When the Moon, rotating around the Earth, falls into its shadow, it is observedlunar eclipse. At the end of the lesson, you can talk about the practical use of the law of rectilinear propagation of light (construction, laying roads, determining the height of objects, and so on).
Students' answers
work in groups,
result
1min
Fizminutka
Basics
part (15 min)
View PPT presentation.Watch video
Let's pose the problem: Group work: “Snowball” strategy - the teacher invites students to prepare speeches on the following questions:
1 group “Sun”: What is light? What bodies serve as sources of light? How does the radiation from an iron or boiler differ from the radiation from an incandescent electric lamp?Star - Sun. Law of rectilinear propagation of light.
2.group “Moon”: What is meant in physics by the terms ray, beam of light, point source of light?Shade and partial shade. Solar and Lunar eclipses.Give examples.
Individual work: Self-tests of knowledge
Test:
1. Light radiation....?
A. ...makes various bodies visible;
B. Perceived by the eye; B. Radiates a heated body.
2 . There are light sources
A. ... only natural ones. B. ...only artificial ones.
V. ...natural and artificial
3 . What light source is called a point light source?
A. A luminous body of small size.
B. a source whose dimensions are much smaller than the distance to it.
B. A very faintly luminous body.
4 . How does light propagate in a homogeneous medium?
A. straight. B. curvilinear.
B. Along any line connecting the source and the object.
5 . How are light sources classified?
A. natural and artificial
B. mechanical.V. thermal
6. What is the source of visible light?
A) Heated electric kettle
B) Television antenna. C) Arc during welding
7 . Among the listed sources does not emit light?
A) Bonfire; B) Radiator; C) Sun.
8. What is a shadow?
A) A region of space where, due to rectilinear propagation, light does not reach.
B).Dark place behind the object
B) Unlit place
9. What is penumbra? What should the source be?
A) The place where half the light falls. Extended.
B) A place where there is light, but it is not enough.
C) An area of space where there is both shadow and light. Pointed.
10. Which line is called a light ray?
A) A line emanating from a light source
B The line along which energy from the light source spreads.
B) The line along which light from the source enters the eye.
Examination Click on the correct answers to appear
2. B
3. B
4. B
5.A
6.B
7. A
8. B
9V
Students watch a presentation
discussion of the presentation,
working with a textbook.
Group work: Snowball strategy:
Students individually write down their thoughts and opinions.
(discuss their positions and reach a compromise on this issue and write down the result).
Create a poster, adding concepts in accordance with the topic.
At the end of the discussions, students defend the work of the group, where they express their understanding of the topic, generalize, justify their point of view, and demonstrate the ability to argue their opinion; assessment skills.
Poster protection.
Work in groups, self-regulation.
Students take tests.
Self-assessment
0 errors – 5
1-2 errors - 4
3-4 mistakes – 3
5-6 errors - 2
I'll close
reader
part (8 min)
We solve quality problems.
1. How can light sources be positioned so that during the operation the shadow of the surgeon’s hands does not cover the operation site?
Answer : Place several lamps above your head
2. Why don’t objects give shadows on a cloudy day?
Answer : Objects are illuminated with diffused light, the illumination is the same on all sides.
3. Is it possible to observe solar and lunar eclipses from any point on the Earth’s surface?
Answer : Lunar yes. Sunny no.
4. Can a cyclist outrun his shadow?
Answer : Yes, if a shadow is formed on a wall parallel to which the cyclist is moving, and the light source is moving faster than the cyclist in the same direction.
5. How does the size of the penumbra depend on the size of the light source?
Answer : The larger the source, the greater the penumbra.
6. Under what condition should a body give a sharp shadow without penumbra on the screen?
Answer : When the size of the light source is much smaller than the body size.
Guys! In conclusion, I want to say. A physicist sees what everyone else sees: objects and phenomena. He, like everyone else, admires the beauty and grandeur of the world, but behind this beauty accessible to everyone, another beauty of patterns in the infinite variety of things and events is revealed to him.
Children, love physics!
She is always, everywhere.
Will help you with the ability,
Both in life and in work!
Lesson summary (3min)
Summing up the lesson,
assessment,
peer assessment
Strategy “Two stars and a wish” - students give 2 stars and write down why, express one wish, which, in their opinion, will improve this work.
A word from the expert council
Reflection “Starry Sky”
Home rear
(2min)
§61,62, 63
Grateful High School
An open lesson in physics in grade 8 “B” on the topic
Prepared by physics teacher R.T. Kuspakova
Aktobe
2015-2016 academic year
When illuminated by a light source whose dimensions are comparable both to the size of the body and to the distance between the source and the body. The penumbra is the periphery (outer part) of the darkened area. In the penumbra region, only part of the light source is visible. This distinguishes it both from complete shadow, in which the source is not visible at all, and from complete light: in the light it is completely visible.
Penumbra (outer part of the shadow) from celestial body, can be observed, for example, with partial eclipse Sun, when the observation point falls into the penumbra formed Moon in a stream of sunlight.
IN fine arts, in particular in photos, by penumbra we mean not so much space as an area surfaces body as an element chiaroscuro- weak shadow, gradation of light and shade on the surface of an object, occupying an intermediate position between light and deep shadow. Penumbra occurs when an object is illuminated by multiple sources. Sveta, on a surface facing the light source at a slight angle.
In everyday speech, penumbra can be called any thin (weak, transparent, pale shadow) that appears in low light.
Literature
- Yashtold-Govorko V. A. Penumbra // Yashtold-Govorko V. A. Photography and processing. Photography, formulas, terms, recipes. Ed. 4th, abbr. M., Art, 1977.
Wikimedia Foundation. 2010.
Synonyms:See what “Penumbra” is in other dictionaries:
Penumbra… Spelling dictionary-reference book
The space between the areas of complete shadow and full light, formed behind an opaque body when illuminated by a light source with large angular dimensions (Fig.). In the P. area, only part of the source is visible (in the shadow the source is not visible at all).... ... Physical encyclopedia
PENUMADOR, partial shade, about partial shade, in partial shade, female. Sparse shadow, very dimly lit place. “The distant threshing floor is barely noticeable in the partial shade.” A.K. Tolstoy. Ushakov's explanatory dictionary. D.N. Ushakov. 1935 1940 ... Ushakov's Explanatory Dictionary
PENUMADAR, and, about partial shade, in partial shade and in partial shade, pl. and, to her and to her, wives. Faint transparent shadow. In the partial shade of foliage. Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 … Ozhegov's Explanatory Dictionary
Noun, number of synonyms: 2 shade (34) chiaroscuro (3) ASIS synonym dictionary. V.N. Trishin. 2013… Dictionary of synonyms
penumbra- penumbra, gen. penumbra, prev. about partial shade, in partial shade and in partial shade; pl. penumbra, gen. penumbra and obsolete penumbra... Dictionary of difficulties of pronunciation and stress in modern Russian language
The space between areas of complete shadow and complete light. It is formed behind an opaque body when illuminated by a light source, the dimensions of which are comparable both to the size of the body and to the distance between the source and the body (Fig.). In the area... ... Great Soviet Encyclopedia
penumbra- pusšešėlis statusas T sritis fizika atitikmenys: engl. half shade partial shadow; penumbra vok. Halbschatten, m; Penumbra, f rus. partial shade, f pranc. pénombre, f … Fizikos terminų žodynas
G. 1. Thin, pale shadow. 2. Dimly lit space between complete shadow and full light. Ephraim's explanatory dictionary. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language by Efremova
1. penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra 2. penumbra, partial shade, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra, penumbra,… ... Forms of words
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