ЭЛЕКТРОННЫЙ МИКРОСКОП.
ЦЕЛИ:
Развитие познавательных интересов учащихся через нестандартную форму подачи нового материала.
Развитие навыков работы с техническим словарём, техническими текстами.
Применение информационно – коммуникативных технологий на уроках английского языка.
ЗАДАЧИ:
Изучить принцип действия электронного микроскопа.
Познакомиться с технической терминологией на английском языке.
Использовать информационные ресурсы.
ХОД УРОКА.
Организационный момент.
Boys and girls, you have learnt some information about optical instruments in Russian. Now it`s time to talk about them in English. Today we find out the technical characteristics of the electron microscope. Let`s divide into groups. The first computer is for those who are good at physics and maths. It`s the first group. The second one is for those who enjoy playing computer games. It`s the second group. The next group and the third computer is for those who have similar interests in clothes, music, films. The computer number four is for those who like doing experiments. It`s the fourth group.
Проверка домашнего задания.
Well, the electron microscope is used by many scientists. Zhores Alferov is one of them. Tell me about
him. It was your homework. /Уч-ся рассказывают об учёном//На экране – фото Алфёрова/
Основная часть урока.
Now, read and translate the text about the electron microscope, and then we`ll do some tasks. You may use these phrases./На экране – фразы, у детей на компьютерах – текст об электронном микроскопе/
Check your translating:/Озвученные фразы на русском выделяются цветом в тексте и у детей,
и на экране/
электронный микроскоп – the electron microscope
волновые характеристики – the wave characteristics
пучок электронов – a beam of electrons
до изобретения этого прибора – until the invention of this instrument
достижимое увеличение – the magnification obtainable
отличается друг от друга – distinguish from each other
в качестве осветителя – as the illuminant
скорость электронов – the velocity of the electrons
магнитные линзы – a system of magnetic lenses
фокусирование пучка – focusing the beam
полученное изображение –the resulting image
особый вид фотопластинки – a special type of photographic plate
огромное увеличение – the tremendous magnifications
напряжение – potential
Thank you. Well done. Now, find your own task in your file. You have 4 min. /у каждой группы своё задание, выполненные задания отсылаются на главный компьютер, появляются на экране и сообща проверяются; каждая группа специальными карточками с баллами/
The 4th group – to find physical terms from the text
The 3d group – to give the specific features of the electron microscope
The 2nd group – to match synonyms and antonyms
The 1st group – to give a summary of the text
To summarize your knowledge of the subject I suggest doing a test. Open the file “Test”.
You can get one more mark. /уч-ся выполняют тест, пересылают его учителю; в последствии он его проверяет и ставит оценку/
Задание на дом.
You know all about the electron microscope. For homework, find some information about
experiments using the electron microscope.
Приложение1
The electron microscope.
The wave characteristics of a beam of electrons have been put to the most beneficial use in the electron microscope. Until the invention of this instrument just before the Second World War, the magnification obtainable with a microscope was limited by the wavelength of visible light. This is because two points on a microscope specimen cannot be distinguished from each other if they are not least as far as apart as half the wavelength of the light are used to illuminate them. By using a beam of electrons instead of light as the illuminate them. Bu using a beam of electrons instead of light as the illuminant, virtually any wave length can be used by controlling the velocity of the electrons electrically. Thus, by subjecting a beam of electrons to a potential of 10000 volts, a wavelength of about 10 – 9 centimetres is obtained, compared to visible wavelength of the order of 5*10 – 5 centimetres. Glass lenses cannot be used with electron microscopes, instead a system of magnetic lenses is used for focusing the beam, and the resulting image is photographed on a special type of photographed plate. With the tremendous magnification possible with this instrument, objects as small as individual viruses can be clearly photographed and observed.
Приложение 2
PHRASES
1. have been put to the most beneficial use –
наиболее успешно использованы
2. at least as far apart as-
по крайней мере на таком расстоянии друг от друга, как…
3. by subjecting a beam of electrons to-
подвергая пучок электронов…
Приложение 3
TASKS
№4: To find physical terms from the text, read and translate them.
№3. To give the specific features of the electron microscope.
№2 1. the wave characteristics a) apparatus
b) tension
2. magnification c) vibration
d) device
3. instrument e) enlargement
4. a potential
№1 to give a summary of the text.
Приложение 4
TEST
What does a microscope do?
It makes things look smaller
It magnifies
It keeps things the same size
The optical system of a microscope consists of ------ lenses?
2
3
4
When did the fast spread of microscopes begin?
1667
1609
1646
What is used for getting an image in the electron microscope?
A beam of electrons
Light rays
Proton stream
How does the estimated power of a microscope depend on the wavelength?
Magnifies it
Decreases it
It doesn’t depend on it
What nature of light are diffraction, dispersion, and interference related to?
Corpuscular
Wave
Corpuscular-wave
7. The estimated power of the electron microscope exceeds the estimated power of an optical one by ---- of times.
a. Tens
b. Hundreds
c. Thousands
How is the wavelength of electrons changed in the electron microscope?
The frequency of the source is change
The velocity of the electrons is changed
The angle of the dip of a beam is changed
