10. Прочитайте текст.

How Fire Works

Fire is extraordinarily helpful. It gave humans the first form of portable light and heat. It also gave us the ability to cook food, forge metal tools, form pottery, harden bricks and drive power plants. There are few things that have done as much harm to humanity as fire, and few things that have done as much good. It is certainly one of the most important forces in human history. But what is it, exactly?

The ancient Greeks considered fire one of the major elements in the universe, alongside water, earth and air. You can feel fire, just like you can feel earth, water and air. You can also see it and smell it, and you can move it from place to place.

But fire is really something completely different. Earth, water and air are all forms of matter - they are made up of millions and millions of atoms collected together. Fire isn't matter at all. It's a visible, tangible side effect of matter changing form – it is one part of a chemical reaction.

Typically, fire comes from a chemical reaction between oxygen in the atmosphere and some sort of fuel (wood or gasoline, for example). Of course, wood and gasoline don’t spontaneously catch on fire just because they’re surrounded by oxygen. For the combustion reaction to happen, you have to heat the fuel to its ignition temperature.

A side effect of these chemical reactions is a lot of heat. The fact that the chemical reactions in a fire generate a lot of new heat is what sustains the fire.

Many fuels burn in one step. Gasoline is a good example. Due to heat, gasoline vaporizes and it all burns as a volatile gas. There is no char.

The dangerous thing about the chemical reactions in fire is the fact that they are self-perpetuating. The heat of the flame itself keeps the fuel at the ignition temperature, so it continues to burn as long as there is fuel and oxygen around it. The flame heats any surrounding fuel so it releases gases as well. When the flame ignites the gases, the fire spreads.

On Earth, gravity determines how the flame burns. All the hot gases in the flame are much hotter (and less dense) than the surrounding air, so they move upward toward lower pressure. This is why fire typically spreads upward, and it’s also why flames are always “pointed” at the top. If you were to light a fire in a microgravity environment, say onboard the space shuttle, it would form a sphere!

11. Найдите в тексте (задание № 10) и выпишите английские эквиваленты к данным словосочетаниям.

1. огонь распространяется вверх

2. пламя воспламеняет газы

3. пока есть топливо и кислород

4. огонь полезен

5. считали огонь одним из важных элементов

6. огонь – вообще не материя

7. загораться спонтанно

8. температура воспламенения

9. летучий газ

10. поддерживать огонь

12. Закончите предложения, выбрав подходящее слово. Переведите предложения на русский язык.

fire chemical reaction forces fuel volatile gas

1. It is certainly one of the most important _______in human history.

2. You can also see _______and smell it

3. Fire is one part of a _________

4. Due to heat, gasoline vaporizes and it all burns as a _________.

5. The heat of the flame itself keeps the _______at the ignition temperature.

13. Ответьте на вопросы к тексту из задания №10.

1. Why is fire extraordinarily helpful?

2. In what way is fire different from earth water and air?

3. Where does fire come from?

4. What sustains the fire?

5. Where do all the hot gases tend to move?

14. Переведите предложения на английский язык, пользуясь лексикой текста (задание №10).

1. Огонь очень полезен для людей.

2. Огонь – это одна часть химической реакции.

3. Для горения необходимо нагреть горючее вещество до температуры воспламенеия.

4. Горение будет продолжаться пока есть топливо и кислород.

5. Когда пламя воспламеняет газы, огонь распространяется.

15. Прочитайте текст и составьте реферат на английском языке, опираясь на следующий план:

1. Название статьи, автор.

The title of the article is …– Заголовок статьи…

The article under discussion is … – Статья, которую мне сейчас хочется обсудить ...

The author of the article is … – Автор статьи …

It is written by … – Она написана …

2. Тема, логические части.

The topic of the article is … – Тема статьи …

The article under discussion is devoted to the problem … – Статью, которую мы обсуждаем, посвящена проблеме …

The author in the article touches upon the problem of … – В статье автор затрагивает проблему ...

The article under discussion may be divided into several logically connected parts which are … – Статья может быть разделена на несколько логически взаимосвязанных частей, таких как …