Sixth Week of Teaching Practice

Hi all,

      This week's blog will be about my teaching practice experience of my past week. It's been a great week. Last week the conscientization program has made a great impact on students. There has been a great response from the students regarding eating healthy foods and avoiding Junk foods. Let's look at the classes I was able to take.
Topics covered this week

• Water- the universal solvent,
• Soft Water and Hard Water.

Water- the universal solvent

• Class began with the concept of recalling the concept of solvent and recognizing the concept of universal solvent. 
• One of the students was asked to dissolve vinegar in a glass of water and observe it carefully.
• Students found out that, "When substances dissolve in water they acquire the property of the substance dissolved" after tasting the solution.
• Students were given another activity. They were asked to take distilled water in three test tubes. Two drops of hydrochloric acid solution added to one test tube and two drops of sodium hydroxide solution to another one. Small pieces of pH paper were dipped, blue litmus paper and red litmus paper in all the three and were asked to observe what happens to the nature of water and Record the observations.
• Students understood that Pure water has neither the properties of acid nor those of alkali. Hence it is called a neutral solvent.
• Since water can dissolve various substances and is widely used for preparing solutions, it is a universal solvent.

Soft Water and Hard Water

• Class began with the discussion on washing clothes and arrived at the concept of Soft Water and Hard Water.

• Activity given: Take three test tubes containing water in which the bicarbonate, chloride, sulphate of calcium is dissolved. Take pure water in another test tube. Put small soap pieces of equal size in all the test tubes. Shake the test tubes well. 
• Questions asked: 
• In which of these test tubes do you see more lather? 
• Why does soap not lather easily in other solutions?

• Students understood that, The water in which soap does not lather easily is called hard water. Here, the hardness of water is due to the presence of dissolved salts of calcium. Water in which soap gives lather readily is called soft water.

• Hard water is formed due to the dissolution of the salts of calcium and magnesium present in soil and rocks as rainwater seeps through the soil. Hard water does not give easy lather with soap because the salts of calcium react with soap to form insoluble salts.

• The hardness of water containing Calcium or Magnesium, bicarbonates is removed during boiling. This type of hardness of water is known as temporary hardness. The hardness of water containing the chlorides and sulphates of calcium and magnesium is not removed even after boiling. This is a permanent hardness.