Solutions

We know that to some extent water dissolves nearly everything with which it comes in contact. So water forms solutions with solids, liquids and gases. A solution is any chemically and physically homogeneous mixture of two or more substances. We can speak about solutions of solids in liquids, liquids in liquids gases in liquids, solids in solids, etc.

Depending upon¹ the size of the dispersed particles, we recognize true solutions, colloidal solutions and suspensions.

A suspension is formed, for example, if we shake fine sand with water. The sand particles are comparatively large and consist of many molecules. As soon as² we stop the agitation, the sand particles begin settling to the bottom of the vessel.

On the other hand,³ a true or molecular solution is formed if we dissolve some sugar in water. Here, the sugar particles are of molecular sizes. They cannot be seen with the naked eye⁴, and they do not tend to settle unless⁵ the solution is saturated.

Colloidal solutions occupy an intermediate position between true solutions and suspensions.

From the pharmaceutical point of view, solutions of solids in liquids are the simplest and the most important liquid dosage forms. Apart from distilled water, the most common solvents for medicines are alcohols, oils, glycerine, ethers, liquid petrolatum etc.

A suspension is a liquid dosage form that consists of very fine insoluble solid particles of medicines suspended in a liquid. An emulsion is a kind of stable suspension of fat drops in water. True (or seed) emulsions are made from hemp seeds, poppy seeds, almonds that contain oils and natural emulgents. Solubility is the ability of substances to dissolve in other substances.

The extent of solubility of different substances varies from almost imperceptible amounts to relatively large values, but for any given solute, the solubility is constant at constant temperature.

Notes.

1.depending upon – в залежності від

2.as soon as – як тільки

3.on the other hand – з іншого боку

4.the naked eye – неозброєне око

5.unless – якщо (тільки) не.

Unit 3: Grammar. The Present/ Past Simple (Indefinite) Forms

Remember the following words and word combinations:

1. hygiene [haidЗi:n] гігієна

2. audience [‘o:djəns] аудиторія, слухачі

3. research [ri’sə:t∫] наукове дослідження, пошуки

4. obtain [әb’tein] отримувати, добувати

5. contamination [kәntәmi’nei∫n] зараження, забруднення

6. improperly [im’propәli] невідповідно, непридатнo

7. maintain [men’tein] підтримувати, зберігати, затверджувати

8. bouquet [‘bu’kei] букет

9. appear [ә’piә] з’явитися, здаватися

10. doctorate [‘doktәrit] докторська ступінь

Louis Pasteu: What his work revealed

Can life appear by spontaneous generation? In the 19th century, some scientists thought so. They felt that life could originate by itself from nonliving matter, without intervention by a creator.

But on a spring evening in April 1864, an audience present at a meeting hall at the Sorbonne University in Paris heard something different. In a masterful presentation before a commission of scientists, Louis Pasteur successfully refuted, point by point, the theory of spontaneous generation. This lecture and later discoveries made him "one of the world’s greatest scientists", as the World Book Encyclopaedia puts it. Louis Pasteur was born in 1822 in the small town in the east of France. His father had ambitions for his son. In spite of having leanings toward art, as well as real artistic talent, Louis took up the sciences. He obtained a doctorate of sciences at the age of 25. Early research of his had to do with tartaric acid, a compound present in the dregs left in wine barrels. Pasteur moved on to the study of fermenting agents.

Prior to Pasteur’s research, the presence of fermenting agents such as yeast was known. But it was thought that they were the result of fermentation. However, Pasteur proved that these fermenting agents were, not the result of fermentation, but rather the cause of it. He showed that each type of fermenting agent caused a different sort of fermentation. The report that he published on this in 1857 is today viewed as "the birth certificate of microbiology".

Pasteur’s research into fermentation enabled him to conclude that microbes caused the majority of problems of contamination in the food industry. Microbes were present in the air or in improperly washed containers. Pasteur suggested that improving hygiene could prevent spoilage of food products by bacteria and that maintaining a temperature of between 50 and 60 degrees Celsius for a few minutes could prevent spoilage of a liquid. This method was first used on wine to prevent abnormal fermentation. The main microbes were killed without causing much change in the taste or bouquet. This process, called pasteurisation, which Pasteur patented, revolutionized the food industry. Nowadays this technique is no longer used for wine but is still adequate for numerous products like milk or fruit juice.

To this day all the evidence from experimentation, history, biology, archaeology and anthropology continues to show what Pasteur demonstrated – that life could come only from pre-existing life, not from inanimate. And the evidence also clearly shows that life reproduces "according to its kind", as the Bible's account in Genesis state. The offspring are always the same "kind" or type, as the parents (Genesis 1:11, 12, 20-25). Thus, knowingly or not, through his work Louis Pasteur provided powerful evidence and testimony against the theory of evolution and for the absolute necessity of a creator for life to have appeared on earth.

Notes

1. to appear by spontaneous generation — довільно самозароджуватися;

2. from nonliving matter — із неживої матерії;

3. without intervention by a creator — без втручання творця;

4. successfully refuted point by point — успішно, крок за кроком спростувати;

5. had ambitions for his son — мав честолюбні плани щодо сина;

6. in spite of having leanings toward — незважаючи на схильність до;

7. to have to do with tartaric acid — досліджувати винну кислоту;

8. the dregs left in wine barrels — осад, що утворюється на дні барил з вином;

9. fermenting agents — речовини, що викликають бродіння;

10. yeast — дріжді;

11. is today viewed as — нині вважають;

12. spoilage of food products — псування харчових продуктів;

13. to prevent abnormal fermentation — запобігати перекисанню;

14. by improving hygiene — дотримуючись гігієни;

15. spoilage of a liquid — псування рідини;

16. from preexisting live — із життя, що вже існує;

17. from inanimate matter — з неживої матерії;

18. knowingly or not — свідомо чи підсвідомо,

19. to provide powerful evidence and testimony against — подати могутній доказ

і свідчення проти;

20. the offspring — нащадок;

21. as the Bible's account in Genesis states — як написано в біблійній книзі

"Буття".