of these metals and the sodium chlorid has become the by-product. The "Stassfurt Salts" constitute one of Germany's richest natural resources. The world's chief supply of bromin and potassium are obtained from these salts. BROMIN. Purpose.-State it on the separate sheet used for record. Apparatus.-15 cm. test tubes with a one-hole cork stopper to fit; L tube; stirring rod. Materials. Concentrated sulfuric acid, potassium bromid, powdered manganese dioxid, carbon disulfid, starch. I. Preparation: Bore a hole through a cork that has been fitted to a 15 cm. tube and insert the short arm of the L tube in the hole. Mix several medium sized crystals, or 1 cc. powdered crystals, with twice its bulk of powdered manganese dioxid and put it in the 15 cm. tube. Adjust the clamp to hold the tube in a slanting position and fill another tube two-thirds full of cold water. Pour 2 cc. of concentrated sulfuric acid into 1 cc. of water and cool it. Then pour it upon the dry mixture in the other tube, insert the cork with L tube, and hold the tube of cold water so that the long arm of the L tube will dip just below the surface of the water. Heat the mixture slowly and constantly with a medium flame until the reddish vapor is driven beyond the bend in the L tube. Do not heat enough to boil the black liquid through the L tube nor stop heating until all the red vapor is driven over. Then stop heating and remove the tube of water at once. The dark liquid in the bottom of the tube is bromin. Describe the action in the generator during the preparation. (?) Diagram the apparatus and label the parts. Write the equation and balance it. The molecule of bromin has two atoms. ?KBr+MnO2+?H2SO→ II. Properties: KHSO4+MnSO1+?+? (a) The colored water above the bromin in the tube is called "bromin water." Pour 2 cc. of it into a 10 cm. tube, add 1 cc. (no more) of carbon disulfid, cover the tube with thumb and shake it. Most of the disulfid settles to the bottom. Compare the colors of disulfid and water, which show the relative solubilities of bromin in the two liquids. (?) (b) Wet a stirring rod and roll it in dry powdered starch. Heat a drop or two of bromin liquid and hold the rod with starch in the vapor of bromin. (?) This effect is used as a test for bromin. (c) Test bromin water with both colors of litmus. (?) Pour some on a little cochineal solution. (?) Note the effect of the bromin on the cork used in the generator. (?) Pour any liquid bromin remaining after tests into the stock bottle of bromin water. (d) Tabulate the physical and chemical properties of bromin. Give the degree of solubility. BROMIN. Experiment 35, Dorothy Borg. Purpose. To prepare and study the properties of bromin. I. Preparation: 2KBr+MnO2+3H2SO4→ 2KHSO4+MnSO4+2H2O+Br2 The substance in the generator has a very dark brown color which, when heated, turns a reddish brown. The heat applied forces the reddish vapor through the L tube into the water forming bromin water. Bromin settles in the bottom of the tube. a. The disulfid is colored much more than the water. b. Bromin colors starch brown. C. Bromin water colors litmus paper red and bleaches it. 3. Sp. gr.-heavier than water. 4. Solubility-less in water than in carbon disulfid. 3. It bleaches calico but does not act as vigorously as chlorin. 4. It attacks cork. The methods mentioned give satisfactory results on the following points: 1. The introduction to experiments gives a working knowledge of the problems involved in the experiment. 2. Training in accurate observation is secured by making the permanent record in the laboratory at the time the results are obtained. 3. The thinking out and writing of record is done at the time and in the place in which the student can have individual instruction from the teacher. 4. The loose leaf experiment sheets placed with the student's record sheets makes a suitable permanent record without any copying of procedure by the student. 5. The loose leaf plan saves time and paper for the student. 6. The loose leaf plan eliminates the drudgery of handling piles of student note books. 7. The loose leaf plan permits collection of student records each day without taking away the assignment for the following day. 8. The loose leaf plan permits carrying student records easily anywhere to be read and graded during the teacher's unoccupied time. 9. The loose leaf plan permits insertion of practical experiments of local interest. 10. Students correct their own mistakes under the supervision of teacher during the following recitation period. 11. The removal of the temptation to unfair practices in doing work promotes general honesty. 12. The study of chemistry is more comprehensible when experiments are grouped under larger heads. 13. The knowledge in the results is developed by the questions to be answered by the student. 14. Library and extra work is systematically developed as optional work. Price of Preprints of the "Status of Mathematics in Secondary Schools." Preprints of this article, published in the January, February, March and April issues, may be had for 10 cents from Mr. M. J. Newell, High School, Evanston, Ill., or from Mr. Alfred Davis, William and Mary College, Williamsburg, Va. THE REORGANIZATION OF HIGH SCHOOL SCIENCE. Illinois State Normal University, Normal, Ill. The day has passed when it was pertinent to ask whether high school science needs reorganization; high school science is now being reorganized. While this reorganization has been taking place some of our scientific friends have been so engrossed in the daily routine of teaching science that they have had no time to glance over their spectacles and note the condition towards which high school science is rapidly drifting. Other of our scientific friends, more alert, have seen with unwilling eyes the drift of science but they have held firmly to the traditions of their own high school and college days; they have rebelled against every innovation; they have contended that the charge that much of our high school science teaching is a near failure from the point of view of the boy or girl is heretical and should be suppressed; they have compared those educators who asked that high school science be reorganized to the boy who cried "Wolf" when there was no wolf; they have said: "Leave high school science alone; we admit that the drift is bad at the present, but the organization and subject matter is the best possible; college and university men approve of it; apparent defects are due to poor teaching and .we are about to remedy that defect." This laissez faire attitude has been most pronounced in teachers of the biological and earth sciences; teachers of physical science have, as a rule, taken more kindly to the demand that high school science be modified, that it be adapted to the interests of high school pupils and to the needs of modern life. Generally speaking, physical geography, physiology, zoology and botany have been the sciences taught in the first two years of the high school course. The laissez faire attitude of the teachers of these subjects, coupled with the growing conviction that the reorganization of high school science must begin at the bottom of the high school science curriculum, is now leading rapidly to the elimination of these subjects from the high school curriculum and the substitution of other subjects which are believed by many to be better adapted to the needs and interests of the pupils in the early years of the high school. The extent to which these four science subjects have declined during the past fifteen years especially during the past five years will be seen by a study of the accompanying graphs and Table I. TABLE I. Table showing per cent increase (bold face) or decrease (light face) during the five years from 1910 to 1915 in the percentage enrollment in the high school science subjects. United States Iowa Wisconsin Illinois Ohio Subject Physics.. Chemistry. 7% 15% 4% 3% 8 Physical Geography 33% Physiology.. 38 31 30% 89 44% 30% 17% 28 Botany.. Zoology.. 50% Agriculture... 24% 52% 231% Domestic Economy. 237% 65% 340% From these data it appears that physics is now nearly holding its own, that chemistry is making slight gains, that physical geography, physiology, botany and zoology are all rapidly losing ground and will soon disappear as high school subjects, or at least they will soon become unimportant subjects in the high school curriculum. It also appears that agriculture and domestic economy are everywhere making rapid gains. It is unfortunate that the reports of the Commissioner of Education, from which these figures are taken, do not show the part which general science is taking in this realignment of high school science.1 It is interesting to note the approximate date at which we may expect physical geography, physiology, botany and zoology to disappear, or practically disappear, from the high school curriculum if their decline continues at the rate indicated from 1910 to 1915. TABLE II. Table showing approximate date at which the science subjects generally taught during the first two years of the high school curriculum may be expected practically to disappear, their places being taken by other subjects. Subject United States Iowa Wisconsin Illinois Ohio It would probably be erroneous to conclude, however, that high school science as a whole is at the present time declining The High School Supervisor of West Virginia in his report for 1915-1916 gives the total ent ollment in high school science subjects in that state as follows: Physics, 831; Chemistry, 992; Botany, 738; Agriculture, 1431; Biology, 2194; and General Science, 1133. A report of the Committee on Science in the High School of Tomorrow, given before the Central Association of Science and Mathematics Teachers, at Columbus, Ohio, November 30, 1917, shows in thirty-six large high schools in the Upper Mississippi Valley, having a total enrollment of 42,107 students, the following percentage enrollment in the sciences: Chemistry, 10.5%; Physics, 10%; Botany, 4.9%; Zoology, 2.3%; General Science, 7.1%; Physiography, 5.4%; Physiology, 2.5%. if we include as high school science agriculture, domestic economy, general science and general biology. A study of the reports of the Commissioner of Education for the past twenty years, incomplete though the reports are, leads to the conclusion that the total percentage enrollment in high school science subjects did decline from about 1900 to 1910 but from 1910 to 1915 there was a slight increase. An analysis of the nature and significance of these shifts in our high school science curriculum is important. It seems fair to presume that, in a large measure, physical geography and physiology have given place to general science as the first-year-science course. Likewise, it is apparent that botany and zoology have given place to general biology in many schools in certain states. and to agriculture in many schools in many states. Domestic economy, without doubt, has displaced the older sciences in many cases. Why were these shifts made? Was it mere caprice, a desire on the part of teacher or pupil, or both, to try something new or different? Or is there a deep-lying conviction held by superintendents, principals, science teachers, and educators in general that the science courses which have been generally offered during the first two years of the high school curriculum are not well adapted to that purpose? The accompanying graphs show that for some years before the advent of agriculture, domestic economy, and general science, all of the old recognized sciences were suffering a rather rapid decline. The truth is that all of the old recognized sciences failed some years ago to command the respect of students of education when regarded as educative materials which would best equip the pupil to take his place as a prosperous and self-respecting citizen in this twentieth-century world. The following five graphs show the percentage of the total number of the public high schools of the United States and in Iowa, Wisconsin, Illinois, and Ohio which were enrolled in the various subjects indicated in 1900, 1905, 1910 and 1915.2 In a measure, teachers and textbook writers of the physical sciences began to recognize the defects in the methods and Note: The data from which these graphs were made are to be found as follows: Summary for the United States from 1890 to 1915, p. 487, Vol. 2, Report of the Commissioner of Education for 1916. For the various states for 1900, pp. 2138-2139, Vol. 2, Report of Commissioner of Education for 1899-1900. For the various states for 1905, pp. 832-833, Vol. 2, Report for 1905. |