Infinitive and its forms:

Infinitive	Active	Passive
Indefinite	to repair	to be repaired
Continuous	to be repairing	____
Perfect	to have repaired	to have been repaired
Perfect Continuous	to have been repairing	____

Exercise 1. Write the appropriate form of the infinitive.

E.g. I worked – to have worked (Perfect infinitive – action refers to past).

1. He has been repairing a refrigerator … .

2. She has worked … .

3. Meat was frozen … .

4. The machines have been examined … .

5. An engineer is checking … .

6. It is boiled … .

7. He will prepare … .

8. The temperature is reduced … .

9. She threw out the leftovers … .

10. Refrigerators preserve foodstuffs … .

Exercise 2. Fill in the correct form of the infinitive.

The device is hot. It must … (to work) for two hours without a break.

The engineer claimed … (to examine) the machines at the time of explosion.

The light must … (to turn off) before leaving the room.

The new refrigerator seems … (to work) properly.

The meat must … (to freeze) as it hasn’t spoilt.

One of the ways … (to preserve) meat is … (to salt) it.

I‘d like … (to enjoy) the sights of some ancient city at the moment instead of doing this monotonous work.

The senior engineer was very upset … (to tell) that there were some problems with the installation of equipment.

The barometer is the instrument … (to show) atmospheric pressure.

… (to explain) the problem he drew a diagrams all over the blackboard.

Exercise 3. Translate into Ukrainian.

To control the operation a worker must know technical process.

One mustn’t change the temperature too often for the conditioner to last longer.

We hope to study more in practice.

The manager asked the work to be done in time.

It was generous of him to have helped me before the lesson began.

They refused to change defective parts.

The young man must have come earlier then we came here.

I want to call Mr.Jones and fax or post him a letter.

He claims to have worked here before.

He looks tired. He seems to have been studying for the test all night.

Discussion:

1. Answer the questions:

Why is a refrigerator called “a miracle of modern living”?

How was food preserved prior refrigerators?

What is the purpose of having a refrigerator?

Can we do without it?

How do we preserve food today?

2. Retell the text.

unit 2.

Understanding refrigeration

I. Warm-up:

Have you ever made any experiments in your chemistry classes? What were they?

Do you know anything about how a refrigerator works?

II. Read and translate the text:

Vocabulary notes:

property -	здібність
to measure up -	вимірювати
thermometer -	термометр
burner -	горелка
to boil -	кип’ятити
sea level -	рівень моря
to heat up -	нагрівати
creature -	істота
liquid -	рідина
air pressure -	aтмосферний тиск

TEXT.

To understand what is happening inside your refrigerator, it is helpful to understand refrigerants a little better. Here are two experiments that help you see what is happening. These experiments can help you understand the properties of gases and their role in refrigeration. Experiment 1.

You will need:

a pot of water;

a thermometer that can measure up to at least 250 degrees F;

a stove.

Put the pot of water on the stove, stick the thermometer in it and turn on the burner. You will see (if you are at sea level) that the temperature of the water rises until it hits 212 F. At that point, it will start boiling, but will remain at 212 F - this is the boiling point of water at sea level. If you live in the mountains, where the air pressure is lower than it is at sea level, the boiling point will be lower - perhaps between 190 and 200 F. This is why many foods have "high-altitude cooking directions" printed on the box. You have to cook foods longer at high altitudes. Experiment 2.

You will need:

an oven-safe glass bowl;

a thermometer that can measure up to at least 450 F;

an oven.

Put the thermometer in your container of water, put the container in the oven and turn it to 400 F.

As the oven heats up, the temperature of the water will again rise until it hits 212 F, and then start boiling. The water's temperature will stay at 212 F even though it is completely surrounded by an environment that is at 400 F. If you let all of the water boil away (and if the thermometer has the range to handle it), as soon as the water is gone the temperature of the thermometer will shoot up to 400 F.

The second experiment is extremely interesting if you think about it in the following way: Imagine some creature that is able to live happily in an oven at 400 degrees Fahrenheit. This creature thinks 400 F is just great - the perfect temperature (just like humans think that 70 F is just great). If the creature is hanging out in an oven at 400 F, and there is a cup of water in the oven boiling away at 212 F, how is the creature going to feel about that water? It is going to think that the boiling water is really cold. After all, the boiling water is 188 degrees colder than the 400 F that this creature thinks is comfortable. That's a big temperature difference!

(This is exactly what is happening when we humans deal with liquid nitrogen. We feel comfortable at 70 F. Liquid nitrogen boils at - 320 F. So if you had a pot of liquid nitrogen sitting on the kitchen table, its temperature would be - 320 F, and it would be boiling away - to you, of course, it would feel incredibly cold.)

Modern refrigerators use a regenerating cycle to reuse the same refrigerant over and over again. You can get an idea of how this works by again imagining our oven creature and his cup of water.

He could create a regenerating cycle by taking the following four steps:

The air temperature in the oven is 400 degrees F. The water in the cup boils away, remaining at 212 F but producing a lot of 400 F steam. Let's say the creature collects this steam in a big bag.

Once all the water boils away, he pressurizes the steam into a steel container. In the process of pressurizing it, its temperature rises to 800 F and it remains steam. So now the steel container is "hot" to the creature because it contains 800 F steam.

The steel container dissipates its excess heat to the air in the oven, and it eventually falls back to 400 F. In the process, the high-pressure steam in the container condenses into pressurized water (just like the butane in a lighter - see sidebar).

At this point, the creature releases the water from the steel pressurized container into a pot, and it immediately begins to boil, its temperature dropping to 212 F.

By repeating these four steps, the creature now has a way of reusing the same water over and over again to provide refrigeration.

Now let's take a look at how these four steps apply to your refrigerator.

III. Comprehension check-up:

1. Make the right choice:

1) To understand the … you need to conduct some experiments:

role of refrigeration;

boiling process;

properties of gases.

2) We can measure up the temperature of water with the help of a … :

thermometer;

burner;

pot of water.

3) Altitude influences much the process of … :

temperature measuring;

water boiling;

refrigeration.

4) A regenerating cycle helps… the same refrigerant again and again:

reuse;

understand;

heat up.

5) A regenerating cycle consists of steam collection, … and steam condensing into pressurized water:

refrigerant reusing;

stem pressurizing;

temperature rising.

2. Put the sentences into the right order according to the text continuity:

For the successful organization of the experiments you will need some water, a thermometer and a n oven.

The second experiment demonstrates the difference in temperatures of boiling water and an environment inside the oven.

To understand the properties of gases and their role in refrigeration you can conduct two experiments.

The first experiment shows the boiling point of water.

This temperature difference explains what happens when people deal with liquid nitrogen.

Then the steam is pressurized and its temperature rises.

Due to temperature difference stem is produced

After pressurization the steam condenses into water which begins to boil.

3. Mark true (T) and false (F) statements. Correct false ones:

The difference in temperatures at sea level and in mountains influences boiling point of water.

The two experiments show how to measure air pressure.

The temperature of water in the oven rises as the oven heats up.

In the mountains the air pressure is higher than it is at sea level.

Modern refrigerators use boiling water.

If liquid nitrogen boiled you would feel incredibly hot.

IV. Vocabulary knowledge check-up:

1. Match the words with their description:

thermometer	to use something for the second time
to heat up	more heat than necessary
to reuse	watery
excess heat	features
properties	a device for measuring temperature
liquid	to make something hot at high temperature

2. Fill in the missing prepositions where necessary:

To conduct the first experiment put the pot … water … the stove and stick the thermometer … it.

When the temperature … water reaches … the boiling point, the water may boil … .

If you are … high altitudes it will take you a long time to cook food.

The temperature … boiling water will stay … the same figure even if it is surrounded … environment … much higher temperature.

A regenerating cycle, used … modern refrigerators, reuses the same refrigerant … and … again

… the process … pressurizing the temperature of steam rises … 80 F.

3. Put the words into the right order to make up correct sentences:

Nitrogen, an, important, in, plays, role, refrigeration.

To, measure up, you, need, temperature, thermometer, a.

If, don’t, boiling, it, boil, away, you, water, will, stop.

Water, when, it, produces, boils, steam, away.

Refrigerators, use, cycle, modern, same, over, a, over, to refrigeration, again, reuse, the, refrigerant, the, and.

V. Controlled Practice:

Functions of the infinitive:

1. Присудок	1. To salt meat is not a good way of preservation.
2. Іменна частина присудка	2. The basic idea of refrigeration is to slow down the process of food spoiling.
3. Додаток	3. Students are taught to mend machines.
4. Означення	4. Refrigeration as the way to preserve food has became popular since the beginning of the 20th century.
5. Обставина	5.To keep food fresh put it into a fridge.

Exercise 1. Change the sentences according to the example.

E.g. Thomson was the first who discovered the electron. – Thomson was the first to discover the electron.

A.Lodygin was the first who invented the electric lamp.

The report contains all the data which must be discussed.

The cooling tower, which will be erected in this region, will be one of the most powerful ones.

The refrigerant which is to be compressed passes through several stages within a compressor.

James Chadwick was the first who discovered the neutron.

A refrigerator uses the evaporation of liquid to absorb heat.

The particles which must be accelerated pass through a strong magnetic field.

The machines parts that must be repaired will be brought next week.

Du Pont was the first who discovered a non-toxic replacement for ammonia.

CFCs which is to be used instead of ammonia is not toxic to humans and safe.

Exercise 2. Translate the sentences into Ukrainian and state the function of the infinitive.

This work can be done in a short time.

The duties of a mechanical engineer ate to repair and maintain the machines.

The most common refrigerant to be used in refrigerators is CFC.

I’m sure he was the first to discover this material.

It is dangerous to use ammonia.

A refrigerator uses water, ammonia and hydrogen to create a continuous cycle for the ammonia.

To produce cold temperature inside a refrigerator liquid ammonia must be mixed with hydrogen and evaporated.

The problem to be removed concerns the operation of the machine.

The ammonia-water solution flows toward the generator to repeat the cycle.

We must check up the new device to make sure it will not do any harm.

Exercise 3. Translate into English.

1. Вказівки, що мають бути виконані, стосуються головного інженера.

2. Для виконання цього завдання знадобиться більше часу.

3. Слід було заморозити продукти, ми могли б використати їх зараз.

4. Лабораторія для проведення експериментів дуже добре обладнана.

5. Зустріч організована для обговорювання наукових досягнень.

6. Слід бути дуже уважним, щоб не зробити більш помилок.

7. Обов’язки інженера – налагоджувати роботу холодильного обладнання.

VI. Discussion:

1. Answer the questions:

What helps us understand the work of a refrigerator?

Why are the two experiments given? What do they illustrate?

What is the essence of these experiments?

Does the temperature of water mean much in this process?

What is a refrigerating cycle?

Why do modern refrigerators use this cycle?

How many stages does the cycle consist of? Describe it.

Does the temperature remain unchanged?

How is the temperature changed?

What does this change show?

2. Retell the text.

Unit 3.

The refrigeration cycle.

I. Warm-up:

What gases do you know?

What gases are used in refrigerators?

II. Read and translate the text: