1. During the ancient era Greek philosophy was the most creative.
2. In ancient times, the systematic study of fundamental natural laws was called natural philosophy.
3. Physics may be divided into classical physics and modern physics.
4. The important laws in modern physics are the conservation laws.
5. Classical physics appeared at the beginning of the 20th century.
Task 5. Choose the correct answer.
1. What does physics deal with?
a) matter and energy and the relationships that exist between them
b) modern and classical physics
c) the conservation laws
2. What is classical physics based on?
a) the laws of motion and gravitation of Sir Isaac Newton
b) the theory of electromagnetic radiation of James Clerk Maxwell
c) both
3. What are matter and energy in classical physics?
a) They are disconnected.
b) They are two interchangeable concepts.
c) Matter is anything that occupies space and has mass; energy is the capacity to move matter.
4. What is modern physics based on?
a) the theory of relativity of Albert Einstein
b) the quantum theory of Max Planck and others
c) both
5. What are matter and energy in modern physics?
a) They are separate concepts.
b) They are alternate forms of each other.
c) Matter and energy are interchangeable.
Task 6. Complete the sentences according to the text «What is Physics?» in your own words.
1. Physics is the science that … .
2. The various laws of physics are … .
3. Classical physics is … .
4. Modern physics is … .
Task 7. Summarize one of the paragraphs of the text.
(See Appendix 1).
Task 8. Enjoy the poem and say the names of the prominent scientists in physics mentioned in the poem.
Unified Field Theory by Tim Joseph
In the beginning there was Aristotle,
At objects at rest tended to remain at rest,
And objects in motion tended to come to rest,
And soon everything was at rest,
And God saw that it was boring.
Then God created Newton,
And objects at rest tended to remain at rest,
But objects in motion tended to remain in motion,
And energy was conserved and momentum was conserved and matter was conserved,
And God saw that it was conservative.
Then God created Einstein,
And everything was relative,
And fast things became short,
And straight things became curved,
And the universe was filled with inertial frames,
And God saw that it was relatively general, but some of it was especially relative.
Then God created Bohr,
And there was the principle,
And the principle was quantum,
And all things were quantified,
But some things were still relative,
And God saw that it was confusing.
Then God was going to create Ferguson,
And Ferguson would have unified,
And he would have fielded a theory,
And all would have been one,
But it was the seventh day,
And God rested,
And objects at rest tend to remain at rest.
UNIT 2. A GLIMPSE OF CLASSICAL PHYSICS
ELECTRICITY AND MAGNETISM
«To cross the seas, to traverse the roads, and to work machinery by galvanism, or rather electro-magnetism, will certainly, if executed, be the most noble achievement ever performed by man».
Alfred Smee[2]
Vocabulary
| accelerate (V) – ускорять attract (to) (V) – притягивать aurora (N) – полярное сияние charge (N) – заряд circuit (N) – цепь, круг, цикл, контур collide ( V ) – сталкиваться compose of ( V ) – составлять constituent ( N ) – составная часть continuum ( N ) – сплошная среда convert ( V ) – трансформировать, преобразовывать current ( N ) – ток, поток, течение due to – благодаря, в результате, из-за emit ( V ) – испускать, выделять excess ( Adj ) – избыточный field (N) – поле hemisphere (N) – полушарие influence (N) – влияние infrared (Adj) – инфракрасный interaction (N) – взаимодействие | lodestone (N) – магнит magnetic (Adj) – магнитный magnetosphere (N) – магнитосфера molecule (N) – молекула needle (N) – стрелка (компаса) permanent ( Adj ) – постоянный pole (N) – полюс property (N) – свойство radio wave (N) – радиоволна repel (V) – отталкивать reverse ( V ) – менять resultant ( Adj ) – равнодействующий, получающийся в результате span ( V ) – охватывать spectrum ( N ) – спектр, диапазон ultraviolet ( Adj ) –ультрафиолетовый vice versa – наоборот, обратно, противоположно wander ( V ) – колебаться, отклоняться X - rays ( N ) – рентгеновские лучи |
Task 1. Discuss with a partner.
1. Do you agree or disagree with the quotation above?
2. What is electricity? What is magnetism? Is there any connection between them? Are there examples of electricity, magnetism, electromagnetism around us?
Task 2. Scan the text «Magnetism in Nature» and match the information below with the numbers.
| a) Ancient people were familiar with magnetite | 800 |
| b)The North Magnetic Pole doesn’t correspond with the North Pole | 2,000 |
| c)The magnetic poles tend to vary daily | 50 |
| d)The South Magnetic Pole doesn’t correspond with the South Pole | 500,000 |
| e)The magnetic poles sometimes reverse themselves | 1,600 |
Magnetism in Nature
Most modern applications of magnetism use electromagnetism, which is created using electricity. However, there are several natural occurrences of magnetism.
Lodestone, or magnetite, was the first naturally occurring magnetic material to be discovered by man. Over 2,000 years ago, the Greeks, Romans, and Chinese all knew of lodestones and their magnetically attractive properties. Lodestones are composed of iron (chemical symbol Fe) and Oxygen (O) and have the composition Fe3O4. Lodestones are commonly found in nature, and have been found in large quantities in Scandinavia, South Africa, and the United States, as well as other places. Lodestones are among the strongest natural magnets, but they are relatively weak as compared to the synthetic magnets used in everyday life.
The strongest magnet on the Earth is actually the Earth itself! Although scientists are not absolutely certain of what causes the Earth’s magnetic field, they think it is caused by the liquid outer core of the Earth. This is mostly iron, and scientists believe it flows in currents; the motion of the molecules in these currents is theorized to create the Earth’s magnetic field. The Earth’s magnetic poles are not at the same places as the geographic poles. The North Magnetic Pole is actually in far northern Canada, about 800 miles from the North Pole, and the South Magnetic Pole is off the coast of Antarctica, about 1,600 miles from the geographic South Pole. The magnetic poles tend to wander a bit, sometimes as much as 50 miles in a day. This is due to the interaction of the Earth and the solar wind. In addition to the daily variations, the Earth’s magnetic poles sometimes reverse themselves, with the North Magnetic Pole becomes south and vice versa. When this happens, the Earth’s magnetic field changes direction (and the sale of compasses increases dramatically). This happens about every 500,000 years.
Speaking of compasses, why do compasses point north? The needle of a compass is actually a small permanent magnet. The «north» tip of the compass needle is the north pole of its magnet, and is attracted to the North Magnetic Pole. The north pole of the magnet should not be attracted to the North Magnetic Pole if both are north poles. Similar poles should repel each other, yet the north pole of the compass magnet does indeed point «north». In reality, what we call the North Magnetic Pole is actually the South Pole of the Earth’s magnetic field! Similarly, the so-called South Magnetic Pole is actually the North Pole.
The Earth’s magnetosphere is a region above the Earth’s surface containing charged particles that are affected by the Earth’s magnetic field. It plays an important role in one of nature’s most picturesque magnetic phenomena, the auroras. Sunspots emit a large number of high-energy charged particles, some of which make their way through the Earth’s magnetosphere. These articles create an overload of charged particles in the lower Van Allen belt, which is basically a belt of radiation trapped around the earth. These excess charged particles enter the atmosphere near the Earth’s magnetic poles and collide with gas molecules in the atmosphere. These collisions make the molecules emit energy in the form of visible light. This happens for many molecules; their resulting light display is an aurora. In the northern hemisphere this display is called the Aurora Borealis, or northern lights. The equivalent southern lights are called the Aurora Australis.
Naturally occurring magnets are not used much these days.
(From Electricity and magnetism by John D. Carpinelli)
Дата: 2018-12-28, просмотров: 413.
