- •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
Listen and read the following word combinations:
transmission of heat, transmitted by conduction, iron rod, are adjacent, heat energy, bottom of a vessel, becomes less dense, flows across, pushes up, radiant heat, internal motion, absorbing medium.
11. Listen and repeat in pauses:
Heat can be transmitted by conduction, convection and radiation. The transmission of heat from molecule to molecule is called conduction. Metals are good conductors. The transmission of heat by the movement of the heated masses of liquids or gases is called convection. Heat radiation is due to the internal motion of the atoms and molecules of heat-producing body. Heat radiation travels through the space as a wave. Radiation can travel through a vacuum. It warms only objects on which it falls and which absorb it. It does not heat the medium through which it passes.
12. Listen to these questions on the above text and answer them:
1. How can heat be transmitted? 2. What is called conduction of heat? 3. What is called convection of heat? 4. What is called radiation of heat?
13. Ask questions using the model.
Model: The molecules of a rod receive some heat from the flame.
What do molecules receive from the flame?
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1. The molecules transmit heat along the rod to other molecules. 2. The denser water pushes up the less dense water thus setting up convection. 3. The absorption of heat radiation produces heat in the absorbing medium.
14. Listen to this dialogue and learn it by heart:
— You know that heat is a form of energy. Let us discuss by what methods can heat be transmitted?
— It can be transmitted by different methods. For example, by conduction.
— That's right. It is a way of transmitting heat. By the way, what are the best conductors of heat?
- Metals are. They transmit heat from molecule to molecule. They are said to conduct heat.
- You are right. What do you know about convection?
- Oh, it's a way of transmitting heat too. It is transmitted by the movement of the heated masses.
- Radiation is the way of transmitting heat too. Isn't it?
— Certainly it is.
15. Suggested topic for oral narration:
By what methods can heat be transmitted? Account for the chief difference between these methods. Give an everyday example to illustrate each method.
Additional Material
Read the text and explain that: a) some metals are better conductors of heat than others, b) textiles are bad conductors of heat.
Good and Bad Conductors of Heat
Most metals are good conductors of heat, silver and copper being outstandingly good. At the other end of the scale, substances like cork, wood, cotton and wool are bad conductors. Both good and bad1 conductors have their uses. The best kettles are made of copper since heat is conducted most rapidly through this metal. The "bit" of a soldering-iron2 is also made of copper, so that when its tip is cooled through contact with the work heat is rapidly conducted from the body of the bit to restore the temperature of the tip and maintains it above the melting-point of solder.
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Bad conductors have a very wide application. Beginning with our own personal comfort, we prevent loss of heat from ourselves by a covering of poorly conducting material. Textiles are bad conductors of heat since they are full of tiny pockets of air enclosed by the fibers of the material. Air, in common with all gases, is a very bad conductor of heat. We say in ordinary conversation that wool is warmer than cotton. Technically, of course, we imply that it has a lower thermal conductivity than cotton.
Notes
1 both good and bad — как хорошие, так и плохие
2 the "bit" of a soldering-iron — наконечник паяльника
UNIT 10