SUGGESTIONS FOR TEACHERS 



General Suggestions. Please keep in mind that students are being 

 taught and that the subject matter must be adapted to their capacity 

 and needs. Study the experiences and needs of the students and make 

 the subject a living one by presenting it to them in such a way that they 

 will begin to use it immediately. Connect it with their everyday life 

 by drawing on their experiences and home environment. Whenever 

 possible have the students bring the material for classroom use, and 

 have them prepare everything possible. The duty of the teacher is to 

 keep the students busy at something useful. 



The questions and exercises at the close of each chapter will give 

 some suggestions for detailed procedure. Some detailed suggestions 

 for the treatment of a few chapters follow: 



Chapter III. Before assigning any work in this chapter give the 

 students some red and blue litmus paper and have them test many of 

 the substances which they have at home, arranging the compounds in 

 three columns, namely: 



(i) Acids (2) Bases (3) Neutrals 



Tell them that those substances which turn blue litmus paper to a 

 red color are acids, those which turn red litmus to blue are bases, and 

 those which do not affect either red or blue litmus are neutral com- 

 pounds. 



Have them test such compounds as water, milk, lard, vinegar, baking 

 soda, soap, alcohol, etc. 



Limewater can be made by placing about one pound of unslaked lime 

 in four pints of water. Use a tall vessel and shake well after slaking the 

 lime and set it aside for a day or more, so that the undissolved lime can 

 settle, then pour off the clear limewater into a bottle for future use. 



A potash-lye solution may be made of the lye purchased in grocery 

 stores by dissolving it in water. Household ammonia and baking soda 

 may also be obtained from the grocery. 



These bases with vinegar, sour milk, and fruit juices for acids will be 

 sufficient material for classroom demonstration to show the nature of 

 such compounds. If you have an equipped laboratory use the chemi- 

 cals at your disposal, but be sure that you connect the work with the 

 life of the students. 



Have the students make soap at home and bring the finished product 

 to school. Give them the directions for making the soap and supply 

 a small quantity of lye if you have it. 



Have the students test their home water to learn whether it is hard 



