Sáng kiến kinh nghiệm Giải pháp nâng cao hiệu quả giảng dạy mạch điện mắc phối hợp các phân tử R, L, C

Vật lý là bộ môn khoa học tự nhiên nghiên cứu về các hiện tượng xảy ra có tính qui luật trong tự nhiên. Những thành tựu của Vật lý được ứng dụng vào thực tiễn cuộc sống và ngược lại chính thực tiễn cuộc sống đã thúc đẩy khoa học Vật lý phát triển. Vì vậy, học Vật lý không chỉ đơn thuần là học lý thuyết Vật lý mà phải biết vận dụng kiến thức ấy vào thực tiễn cuộc sống. Do đó trong quá trình giảng dạy môn Vật lí, người giáo viên phải rèn luyện cho học sinh có được những kĩ năng, kĩ xảo và thường xuyên vận dụng những hiểu biết đã học để giải quyết những vấn đề thực tiễn đặt ra.

Bộ môn Vật lý được đưa vào giảng dạy trong nhà trường phổ thông nhằm cung cấp cho học sinh những kiến thức phổ thông, cơ bản, giúp học sinh có khả năng phân tích tổng hợp và có phương pháp làm việc khoa học. Chính vì thế, để học sinh có thể hiểu được một cách sâu sắc và đầy đủ những kiến thức, đồng thời áp dụng được các kiến thức đó vào thực tiễn cuộc sống thì cần phải rèn luyện cho học sinh những phương pháp, kĩ năng, kĩ xảo trong việc giải bài tập, đo lường, quan sát

Phần mạch điện mắc phối hợp các phần tử R, L, C thường xuyên xuất hiện trong các kỳ thi chọn học sinh giỏi cấp Tỉnh, cấp Quốc gia và Quốc tế. Tôi nhận thấy học sinh thường rất lúng túng và gặp nhiều khó khăn khi giải quyết các bài tập về dạng toán này. Trong thời gian giảng dạy phần mạch điện, bản thân tôi đã rút ra được một số giải pháp để nâng cao hiệu quả giảng dạy nội dung này.

 

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wn strategies and bottom-up strategies.
Top-down strategies: require listener’s background knowledge of context, topic, speakers, language to listen for gist (main ideas), details, information sequency, guessing or inferencing.
Bottom-up strategies: require students to concentrate on specific points (such as intonation, grammar points, linking words.)
Definition of Authentic materials:
When it comes to authentic materials, Widdowson wrote: 
“It has been traditionally supposed that the language presented to learners should be simplified in some way for easy access and acquisition. Nowadays, there are recommendations that the language presented should be authentic” (Widdowson 1990:67).
The definitions of authentic materials have been a much-discussed point. Harmer (1983) claims that “authentic texts (either written or spoken) are those which are designed for native speakers: They are real text designed not for language students, but for the speakers of the language in question”. They are defined as “materials that have been produced tofulfil some social purpose in the language community.” (Peacock (1997)), so they totally are not spoken for pedagogic purposes. In trying to define authentic listening materials, Underwood (1989) uses phrases like ‘real Speech’, ‘not specially designed for foreign learners’, ‘natural conversation’, ‘what people say in real life’, ‘what native speakers say when talking to each other’.
As some definitions are considered above, we can see that listening authentic materials are spoken by the native speakers and not designed for language teaching. In this understanding, a sheer volume of authentic materials can be found mostly on Internet such as broadcasts, official speech, radio, TV programs or even films. 
According to Gebhard (1996), authentic materials can be classified into three categories: Authentic Listening-Viewing Materials (TV commercials, quiz shows, cartoons, news clips, comedy shows, movies, soap operas, professionally audio-taped short stories and novels, radio ads, songs, documentaries, and sales pitches), Authentic Visual Materials (slides, photographs, magazine) and Authentic Printed Materials (newspaper articles, movie advertisements,). 
This paper only focuses on the first types of authentic listening materials which are seen as genuine monolongues or dialogues by native speakers for their social purposes. Thus, let see how they exert their impact on improvement of listening skills of English gifted students
Types of listening exercises:
In listening practice, there are a wide range of exercises. According to Ur (1984), listening exercises can be categorized into four main groups: listening with no respond, with a limited respond, with a long respond and with an extended respond. Students at grade 10 mostly focus on two types: listening with a limited respond and with a long respond. 
Listening with a limited respond: Exercises are designed with the hope of receiving limited responses from students. The possible actitivies are shown below: 
Following the instructions 
Ticking of the words they heard 
True or false activities
Spotting the difference.  
Guessing.  
Describing
Listening with a long respond: Exercises are designed with the demand for giving comprehensive answers in order to prove their understanding of the text, involving these activities:  
Summarizing 
Paraphrasing and translating 
Gap filling 
Answering questions (The most common form of this exercise is a multiple choice). 
Application:
Sources of authentic materials:
The factual situation of 10th grader’s listening ability, to some extent, shows some problems as follows: (1)sources of listening materials are of unreliability or deficient authenticity ( for example random internet recordings, youtube clips, pop song); (2)Teachers are yet to take maximum advantages of listening materials; (3)Students are not informed fully at least primal listening techniques.
Accordingly, as mentioned before, the coming-first solution for these problems is to find the authentic materials. With the technological advances, it is easier to access the rich sources of authentic materials from Internet. Take some possible types of authentic materials for example: BBC News, Breaking News English, VOA Special English, British Council Podcasts, TedTalk, SBS (the service broadcast of Australia), CNN radio and so forth. At the same time, teachers are expected to explore and design the suitable listening activities for student’s practice
In a deeper analysis, there are three main authentic sources of listening:
Radio: Using radio can expose students to real speech in their target language with a broad range of social aspects and topics (e.g. BBC, VOA, CNN, SBS)
 TV programs: Also provide various topics of culture, science, nature, entertainment with visual aids which make TV Programs attractive (e.g. National Geographic Channel)
Audio tapes and videos: audio recordings about a variety of listening situation, speakers, accents or audio books; videos designed with dynamic and interesting effect or video-recorded lectures British Council Podcasts, TedTalk)
In the this process of applying the given solution in real gifted class, the motivation factor can not be ignored since not just listening practice, all other types of English skills practice considerably require the need of motivating students. The most feasible way is choosing the topical events or controversial topics in every aspects of life. Students likely want to show their interest in matter of considerable public concern. 
BBC News as the focused authentic material
Within the scope of this paper, in this part, the focusing application is using BBC News in boosting students’ listening skill. As regards the brief information about it, it is a part of British Broadcasting Corporation with a responsibility of gathering and broadcasting of news and current affairs. I collect 10 different news reports from BBC News on topics of our daily life and topical events. Five news from these 10 collecting ones mentioned above will be chosen to design listening tasks. The topics of these 5 news are: Women’s right to vote” ( 6 minutes) ,“Chinese taxi drivers learn English” (nearly 3 minutes), Who do you think you are?”, “Is English changing?” “How to prepare for an exam”. I will concentrate on analyzing the possible confusions when doing exercises on the first two news. By doing this, students can obtain some techniques to do True/False task as well as the useful language (words, phrasal verbs or nouns)
Authentic materials are applied in designing True/False exercise:
These recordings can be useful materials for designing a range of different listening exercises. I opt for only one type of exercises which is True/False exercise to design and analyze two news. Doing this task requires the strategy - listening for specific information in which students have to learn intensively and find out specific details. The reason for choosing this kind of task is that it seemingly causes listeners a lot of confusions when they have to decide whether the sentences are true or false. Exercises are designed from two news as follows: (Besides, I also design 3 additional news with other listening exercises at the end of this part)
News 1: “Women’s right to vote”
You are going to hear two news hosts Alice and Neil talking about British suffragette leader Emmeline Pankhurst and her struggle to get women a better life. While listening, you have to decide the following statements are true (T) or false (F):
Statements
True
False
Alice have a strong feeling of respect and liking for suffragettes.
Alice thinks they are really brave
Neil’s answer to today’s quiz question is false
In Britain, women’s groups lobbied Parliament for ten years eventually winning the right for all women to vote.
Julia Bush was a charismatic leader, she campaigned with great courage for women
According to Julia Bush, Emmeline Pankhurst was sacked as a result of the parliamentary vote.
Mrs Pankhurst’s expectation for wider reforms was seen as a big challenge.
June Purvis says that despite high determination, it is impossible for women to take actions of interrupting public events.
 Neil shows his positive reaction to the suffragettes’ teashop talks to address the public
 The European war in 1940 contributed to the women’s capability of their good management at home as men away fighting.
 At the end of the news, Neil doesn’t care about the correct answer to today’s quiz question anymore.
Key: 1. T ; 2. F ; 3. F ; 4. T ; 5. F ; 
 6. F ; 7. T ; 8. F ; 9. F ; 10. F 
The topic of this exercise has long been much-mentioned in society but it is crucial background knowledge for our students. As shown above, this exercise may bring out some possibilities of confusing issues for students. The common point leading to students’ confusion is the expressions with the same meaning. Most statements I designed are paraphrased from the original transcipt or containing the synomous words/word phrases. Therefore, students are required to truly understand what speakers means in order to get the correct point of the statements. For instance, in senttence 1, “have a strong feeling of respect and liking for” is similar to “have great admiration for” in the recording. In sentence 4, “ten years” is equal to “a decade”. If students can not recorgnize this, they will have great confusion in deciding the statements are corrected or not. Statements number 5 to 8 are paraphased in term of content in a little higher difficulty level, demanding for students’ comprehension.
Another thing to be cautious about is to identify two voices of speakers (usually female vs male). Take sentence 2 as an example, the statement mention the thoughts of one of two speakers in the talk. Students thus need to pay more attention to different voices. 
In sentence 3, students may get confused when they hear the word “right” in Alice’s response to Neil’s answer without listening to the rest of sentence. Alice says the word “right” but add that let’s see later on in the show. Hence, students should not jump into conclusion so quickly when hearing this kind of ‘distracting’ word.
The 10th statement draws students’attention to listen to numbers. There is usual confusion in differentiating “fourteen” and “fourty”. Teachers need to make sure students all know that the word stress of thirteen, fourteen, fifteen is at “teen” syllable and in contrast, numbers with the ending “ty” have the first-syllable stress.
Sentence 9 is about his reaction to an event. In his answer, he says an exclamation word: “Indeed!” which shows the postive emphasis on Alice’s ideas before. In sentence 11, Neil says “come on” which is a spoken expression used to hurry someone. In this case, Neil can’t wait to hear the answer. Through these sentences, students must get familiar with spoken language that may show speakers’ attitudes
News 2: “Chinese taxi drivers learn English”
You are going to hear a news report from Rubifield Hayes about the real situation of taxi drivers learning English in China. While listening, you have to decide the following statements are true (T) or false (F):
Statements
True
False
Across Beijing, 60,000 taxi flyers are being drilled in the rudiments of English
 Mr Jin is a fashion model in Beijing
In reality, most Beijing taxis have very poor facility condition 
All taxi drivers still want to spare time learning English despite the long working hour
It is not until the next 6 years that the Olympics starts
Key: T – F – T – F – T
Transcript: Now in the Chinese capital Beijing preparations to host the Olympic games in 2008 are being taken very seriously indeed in training the city’s notoriously grumpy taxi drivers.
In Beijing, a revolution is underway. Welcome to Beijing In classrooms across the city 60,000 taxi drivers are being drilled in the rudiments of English. The city prepares to host the Olympic Games, the notoriously grumpy taxi are being ordered to clean up their act.
Sleeping in English teaching cassette, Jin Fang Chen heads off on his morning rounds. Cean-cut, light, his car is always immaculate. Jin is a model student.
 Unfortunately, the reality of most Beijing taxis is still rather different. Engine wheezing tires that have seen much better days, shoehorned into the tiny cab with suspension that puts you in touch with every bump in the road. Don’t even mention the air-conditioner and how about those English classes.
There are so many problems. Cars are all absolutely filthy. Sometimes the drivers don’t even know where they’re going but spare a thought for the drivers working 13 hours a day, 7 days a week, meals grabbed on the houfe and now they’re expected to learn English as well. For some, it’s too much
.. There are still six years to go before the Olympics 
Statement 1 poses a posibility of confusion by the words pronunciation: “drivers” and “passengers” in a rapid speed of the news. It is likely that students may miss a specific word as listening to a long rapid sentence. In this case, the possible way is to listen carefully to the context after that to guess.
The meaning of the word “model” in the second statement (fashion model) is different from “model” from the news (model student). This is the case of polysemous words which are the words having more than one meaning. 
In the forth sentence, students may also hear “spare” in the news. However, its meaning also difers from “spare time”. In this case, one word with same meaning but it can be understood differently in each context or when it goes with different noun objects
News 3: “Who do you think you are?”
How do you see yourself and how do others see you? Alice and Neil discuss identity and how appearances can be deceptive. While listening, you have to fill in the blanks with the suitable words:
Alice sees Neil as male, Caucasian, .., short auburn hair, bushy eyebrows, thin lips
Neil thinks .. UK population describe themselves as ethnically mixed.
If a girl is described as English rose, she is attractive with a pale delicate.............
Neil’s friend is a real mix
Sarah Jones ‘s mother is actually .
The United States is considered a real .. 
People think Sarah is raised by parents who aren’t  her
According to Julian Baggini, our sense of self creates our sense of 
Key: 1. Early 40s ; 2. 0,9% ; 3. Complexion ; 4. Ethnic ; 5. Mixed
6.melting pot ; 7. Biologicially ; 8. identity
News 4: “Is English changing?”
Will we still be speaking in an English we recognise in a thousand years' time? Which words and grammar will still be there? And which will have been lost? Alice and Neil make some educated guesses! Listening and answer the following question in NO MORE THAN FOUR WORDS:
What is changing in the topic of the show?
What does the word “plos” mean in text speak?
What does Alice think about the word “shall”?
Struggle for life can happen in language. So what are competing with each other?
What happens to the modal verb ‘must’?
When did Progressive tenses start to increase dramatically?
What is the slogan used by an American fast-food chain?
Where does Professor Mark Pagel work at?
Key: 1. English language; 2. Parents look over shoulder;
	3.old fashioned; 4. Similar words ; 5. Decline rapidly
	6. the 19th century; 7. I’m loving it; 8. Reading University
News 5: “How to prepare for an exam”
Students up and down the UK are busy revising for exams. Alice and Rob consider which study techniques are effective – and which aren't – including Rob's suggestions to sleep with his textbook under his pillow and singing in the shower. Listen and choose the best option:
What grades did Rob get at schools?
Very good grades	B. Not good grades
C.Very bad grades	D. Good grade
 2. The first study method mentioned in this talk is ..
	A. book-under-the-pillow	B. paper-under-the-pillow
	C. right book-under-the-pillow	D. work at night
 3. One of Rob’s top tips is 
	A. summarising	B. highlighting
	C. underlining	D. cramming
 4. What steps does John Dunlosky says about how to memorise?
	A. Read textbook -> highlight -> reread -> test yourself
	B. Read textbook -> color any images -> make flashcards
	C. Highlight -> read textbook -> test yourself -> reread
	D. Read textbook -> highlight -> make flashcards -> test yourself
 5. By testing youself in repeated way, you will ..
	A. strengthen your brain
	B. strengthen the pathways between the neurons
	C. strengthen nerve cells
	D. weaken the pathways between the neurons
 6. Testing yourself repeatedly over a long time period is called .
	A. distributed practice
	B. effective way
	C. attributed practice
	D. learning effectiveness
 7. What does Rob do before his French exam?
	A. cram the French words
	B. practice French songs
	C. take a shower
	D. sing irregular French verbs.
 8. What research suggests a good learning strategy for certain things?
	A. Pneumatics
	B. Mnemotics
	C. Hypnotics
	D. Phonetics 
Key: 1. B	;	2.A	;	3.B	;	4.D
 5.B	;	6. A	;	7.D	;	8.B
PART C: CONCLUSION
Summary:
All things considered, utilizing authentic listening materials is of prime importance in improving listening skill of the special target learners – 10th grade English gifted students. They will apparently gain a great deal of knowledge and skills as well if teachers have good approach and appropriate task design. Listening to real language which is not for normal language learners is an obvious challenge at first; notwithstanding, I strongly believe that with intensive practice, their listening skill will upgrade to a whole new level and more importantly, gifted students considerably benefits from authentic materials and accumulate their knowledge for their later academic study.
Further suggestions:
A variety of listening tasks are needed to be designed by teachers with good preparation and time investment. Teachers should stage the listening by starting with the simple one and then more demanding one. Thereby, the authentic materials are made good use of. Particularly, each type of tasks aims at a certain aspect of language. For example, True/False statements exercise analyzed in this paper shows its function of providing students with techniques of listening for specific information (including words, numbers, spoken language, synonym), in which tasks need to be ordered in ascending difficulty in order not to discourage students
Pre-listening activity is necessary for students to get the overall ideas of the recordings as well as introduce possibly new knowledge. For instance, when listening to a news on BBC News, teachers can give them information about the countries, places, people, contexts relating to that topic. At the same time, extra-activies can be designed to motivate students or raise their interst.List of references:
Lindsay, C. and Knight, P. (2006) Learning and Teaching English. Oxford: OUP
Jack C.Richards (2008). Teaching Listening and Speaking From Theory to Practice. Retrieved from:  
Buck, G. (2001). Assessing Listening.Cambridge: Cambridge University Press
Goh, C., and T. Yusnita (2006). Metacognitive instruction in listening for 
young learners. ELT Journal60(3):222–232.
Nunan, David.1991. Language Teaching Methodology: a textbook for teachers. Great Britain
Widdowson, H.G. (1990) Aspects of Language TeachingOxford, O.U.P.
Harmer, J. (1991). The practice of English language teaching: new edition. London: Longman. 
Peacock, M. (1997) The Effect of Authentic Materials on the Motivation of EFL Learnersin English Language Teaching Journal 51, pp 2
Genhard, J.G. (1996). Teaching English as a foreign language: A teacher self-development and methodology. Ann arbor: the university of Michigan press. 
Underwood, M. (1989). Teaching Listening. London: Longman
Links of listening recordings from BBC News
(4 first audios in this link)

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