- •Part I
- •Text. Physics and physical phenomena
- •Laboratory Exercises
- •Additional Material
- •M. V.Lomonosov
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Measurement of Volume
- •Text. The metric system
- •Dimensions of a Solid Body
- •Laboratory Exercises
- •Additional Material
- •Origin of the Metric System
- •Text. The kinetic theory and the three states of matter
- •3 Not to matter — не иметь значения will make full use — займут
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Mass and weight
- •3. Much, more, the most; little, less, the least; good, bet ter,
- •4, .,. Er than, more ... Than
- •5. At, on, over .., etc.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text, force, work, energy and power
- •Exercises
- •Additional Material
- •1. Have supported, has altered....
- •2. Energy can be converted...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Isaac Newton
- •Text. Heat
- •1. Heat is known to be a form of energy.
- •2. You place, you placed, you have placed. They take, they took, they have taken.
- •3. Newton began to think about heat.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Transmission of heat
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Good and Bad Conductors of Heat
- •Text. Calorimeters
- •1. It is usual to transfer ...
- •2. There is; is there; there is no ...
- •3. The setting up of ...; the reading of ...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Wave motion and sound
- •1. It does not move forward but returns again...
- •2. It is evident, it is clear.
- •Exercises
- •Additional Material
- •Text. Light
- •1. It becomes red-hot, it is the reason, it was cold...
- •2. High temperature produced by..., in a substance called... . Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Reflection and refraction of light
- •1. Do bodies emit? Does he make? Did it represent?
- •2. Have they shown? Had he travelled? Was it reflected? Is he going? Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Lenses
- •1. After leaving the lens...
- •Exercises
- •Additional Material
- •Text. Simple cell
- •1. The twitching of; the reading of...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Voltaic Cells
- •Text. The accumulator
- •1. A plate containing, a plate being immersed...
- •2. Achieved by connecting; determined by testing...
- •Exercises
- •Additional Material
- •Text. Principle of electric motor
- •1. They are used to pull...
- •2. When viewed, while doing...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Electric Bell Circuit
- •Text. Moving-coil ammeter and voltmeter
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Moving-Coil Galvanometer
- •Text. Electromotive force
Laboratory Exercises
9. Listen and practise the pronunciation of the words ending with the following suffixes: "-s", "-ed", "-ly":
changes, numbers, attracts, laboratories, masses, balances, contains, divisions, happens, remains, weights; weighed, placed, raised, fanned, adjusted; slightly, really, chemically, equally.
10. Listen and repeat in pauses:
The mass of a body is the quantity of matter in it. The unit of mass is the lump of platinum kept at Paris. It is called the standard kilogramme. The weight of a body is the pull with which the earth attracts it. The weight always acts downwards, towards the centre of the earth. The weight of an object is directly proportional to the mass of the object. The mass of an object is constant, its weight can vary and actually decreases with height above the earth's surface.
11. Listen to these questions on the above text and answer them:
1. What is the mass of a body? 2. What is the unit of mass? 3. What is called the standard kilogramme? 4. What is the weight of a body? 5. What varies? 6. What remains constant?
12. Ask questions using the model.
Model: The standard metre is the unit of length.
What is the standard metre?
1. А box of "weights" is really a box of "masses". 2. The standard kilogramme is the unit of mass. 3. Balances used in laboratories are more sensitive. 4. The litre is the unit of volume.
13. Listen to this dialogue and learn it by heart:
— May I trouble you for a moment, please? Certainly, what is it?
— We must weigh some substances for our experiment How must we do it? We don't know.
Oh, it's very easy. You ought to do it in the physical laboratory using a beam balance.
— What is a beam balance?
It's a precise instrument demanding careful handling.
— Thank you very much.
14. Suggested topics for oral narration:
1. Give the definition of a) the weight of a body, b) the mass of a body. What is the difference between them?
2. Describe a beam balance using the figure 2.
3. Describe the process of weighing.
Additional Material
1. Read the texts and find answers to these questions:
1. What does the mass of anything depend on? 2. What changes does a box of weights undergo when taken millions of miles away from the earth? 3. What is the scientific unit of mass? 4. What force is called the weight of a body?
Mass
The weight of any body at a certain place is determined by its mass. The mass of a body may be defined as the quantity of matter in it. The weight of a cake depends upon what is in it, i.e. upon its mass. A small piece of lead will weigh the same as a large piece of wood if they have the same mass. Thus the mass of anything depends not only on its size but on the kind of thing it is, e.g. lead, iron, water, etc.
A box of "weights" is really a box of "masses". It contains pieces of brass each having a standard mass. Since the weight depends upon the mass each piece of brass has a standard mass. It is important to remember that the mass of a body never changes. If you take a box of "weights" millions
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of miles away from the earth so that the earth's pull сan not be felt, the weight of the brass will disappear but the piece of brass, e.g. the mass will be the same.
Even if we melt the brass in a furnace the mass of the liquid formed will be the same as that of the solid brass. The mass of a body remains constant, but its weight changes.'The scientific unit of mass is the gramme. It the mass of 1 c.c. ( cubic centimetre) of water at a tempera-ture of 4°C.
Weight
Any body held in the hand and then released, immedia-tely moves towards the floor. This movement shows that • force is acting on the object. This force is called the weight of the body. It is due to the attraction of the earth and is the most familiar of all forces. The earth attracts all bodies and tries to pull them towards its centre.
All substances have weight, even air and gases like hydro gen and helium which are less dense than air and are therefore used in airships The earth pulls everything downwards and by "downwards" we mean "towards the centre of the earth"
Hence we may say that the weight of a body is the force with which the earth attracts it. This force is directed towards the centre of the earth,
It is very interesting to realize that the weight of a body is quite a scientific property due simply to its nearness to the earth. It is true that we buy coal by weight, but not because of its weight, we buy it for the heat it gives when burned.
UNIT 6