The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924031784162 PHYSICS IN SMALL HIGH SCHOOLS ISSUED BY THE EASTERN ASSOCIATION OF PHYSICS TEACHERS 1910 INSTRUCTION IN PHYSICS IN SMALL HIGH SCHOOLS A REPORT OF A COMMITTEE OF THE Ea^ern Association of Physics Teachers PUBLISHED BY THE ASSOCIATION THE DUNBAR-KBRR CO. 382 Main Street, Malofsn Mass. 1910 CopyrigVited by the Eastern Association of Physics Teachers JOHN W. HUTCHiNS, Chairman of Committee 1910 REPORT OF A COMMITTEE ON INSTRUCTION IN PHYSICS IN SMALL HIGH SCHOOLS To the Eastern Association of Physics Teachers: This committee was appointed to investigate the conditions of instruction in Physics in the smaller High Schools, with the purpose of securing information concerning existing practices, and of rendering such assistance as the Association might be able to give these schools. Since the College Entrance Examination Board has issued a new list of topics and experiments, which will constitute the basis of college examinations, this committee has sought to harmonize these requirements with the needs and limitations of the schools considered in this report. The needs of the larger number of pupils who do not prepare for college have been still more care- fully considered. This committee has sent out a series of questions to 334 New England secondary school principals and has received 183 replies. The schools included in this list are those schools whose enrol- ment was supposed to be between 25 and 150 pupils. ' These replies have been tabulated and a summary of these replies is given in this report, together with the questions asked. Inquiries sent Replies received Me. N. H. Vt. Mass. R.I. Conn. Total 49 42 35 147 13 48 334 24 26 22 73 10 28 183 Classification of replies, showing the number of schools giving definite answers to each inquiry. 1. During what year of the High School curriculum is your course in Physics offered? Schools giving no course ... 7 Alternating years III or IV. .30 Physics given during year I.. 4 Alternating years II or III. . . 3 Physics given during year II. . 15 Schools having two courses Physics given during year III 77 I and III or IV years 18 Physics given during year IV 12 II and III or IV years 16 2. Is this course in Physics required or elective? Schools having Physics elective 66 Schools having Physics required .■•■■. I» Physics elective in some courses and required in others 37 3. How many weeks and how many recitations per week are given to this course? Length of course in weeks: 20 weeks or less 3 schools 30 to 36 weeks 58 schools 37 or 38 weeks 36 schools 39 or 40 weeks 72 schools School exercises per week in Physics: 8 periods per week 2 schools 7 periods per week 6 schools 6 periods per week 1 school 5 periods per week 117 schools 4 periods per week 32 schools 3 periods per week 14 schools 2 periods per week 2 schools 4. What is the length of the recitation period? Of the lab- oratory period? Recitation Periods : Schools giving less than 40 minutes to recitation periods 25 Schools giving between 40 and 50 minutes to recitation periods 144 Schools giving more than 50 minutes to recitation periods 3 Laboratory Periods : Schools giving no laboratory work 12 Schools making laboratory periods shorter than recitations 2 Schools making laboratory periods of same length as recitations 72 Schools making laboratory periods longer than recitation periods 81 5. Number of pupils taking the course in Physics this year? (1909-1910). Schools enrolling no pupils in Physics classes 4 Schools enrolling less than 10 pupils in Physics classes 39 Schools enrolling from 10 to 20 pupils in Physics classes 84 Schools enrolling from 20 to 50 pupils in Physics classes 40 Schools enrolling more than 50 pupils in Physics classes 2 6. Total number of pupils in the school? Schools having a membership less than 50 45 Schools having a membership between 50 and 100 66 Schools having a membership over 100 65 7. What text-book is used as the basis for the course? Andrews and Rowland 1 Gilley ^ Avery 8 Hall & Bergen 14 Carhart & Chute 19 Higgins 17 Cheston and Gibson .,..,.,.. 1 Hoadley 16 Culler 4 Millikan and Gale 59 Fisher and Patterson 3' Mumper 6 Gage 13 Wentworth and Hill 32 8. What proportion of the entire tirae given to Physics is devoted to laboratory work? Schools giving more than two-thirds of entire time 1 Schools giving from one-third to two-thirds of entire time 103 Schools giving one-third or less 53 Schools giving no time 11 9. How much money has been expended during the past three years in purchasing physical apparatus? Schools expending less than $50 48 Schools expending between $50 and $200 72 Schools expending more than $200 ._ 29 10. What annual appropriation is available for this purpose ? Only thirteen schools have regular annual allowances, and these al- lowances are shared with other sciences. 11. What do you estimate the total value of the physical apparatus owned by the school? Schools having no apparatus 11 Schools having not over $100 23 Schools having between $100 and $500 89 Schools having between $500 and $1,000 34 Schools having between $1,000 and $8,000 ". 8 12. Does the course of topics and experiments outlined by the College Entrance Examination Board seem to be adapted to the needs of your school? Schools answering "yes" 95 Schools dissatisfied 23 13. What topics and experiments would you omit from the course proposed? 14. What topics and experiments would you add to the list? Answers given to questions 13 and 14 were very meagre and can not well be tabulated. 15. During the past three years how many students entering college from your school have offered Physics as an entrance sub- ject ?' Schools sending no pupils prepared in Physics 28 Schools sending 5 pupils or less prepared in Physics 62 Schools sending 6 to 10 pupils prepared in Physics 24 Schools sending 11 to 20 pupils prepared in Physics 18 Schools sending more than 20 pupils prepared in Physics 1 16. What other subjects does the instructor in Physics teach? How many recitations per week in each subject ? Teachers instructing less than 10 periods per week besides Physics .... 10 Teachers instructing from 10 to 29 period's per week besides Physics . . 113 Teachers instructing 30 or more periods per week besides Physics .... 23 17. What special preparation for teaching Physics has the instructor in this branch received? Number of teachers having no training beyond a single or required course in college 78 Teachers having some extra courses in Physics in college or in sum- mer schools 49 Specialists, who have taken several college or equivalent courses in Physics 30 In examining this data it must be noted that the large city high schools are not included. Data from such schools would show much more elaborate courses and more costly equipment than schools included in this report can usually expect. There are some apparent discrepancies in the table because only partial reports are given by many schools. The following observations, based upon the data and many letters which accompanied the replies may be noted: — I. Within twenty years the courses in Physics have been gradually changed to the latter part of the high school curricu- lum, and are now given principally in the third and fourth years. II. Notably in Massachusetts two courses in Physics have been established in many of the high schools. (a). An elementary Physics or Science course coming the first or second year, and generally occupying less time than a full year's course. (6). An advanced or college preparatory course in the third or fourth year. III. In many cases the elementary course is required and the advanced course is elective. IV. Very few schools now give less than a full year with five recitation periods per week of forty or more minutes each to the major course in Physics offered. 6 V. Schools of moderate size seem to give relatively more time to laboratory woi'k than the large city high schools. VI. The nmubcr of students taking Physics is a very small proportion of the pupils in the schools, — altogether smaller than the subject merits when considered either from the educational or informational standpoint. This is occasioned in part by the fact that the subject is offered only in the senior and junior years in most schools. • ' -'■- ■ ^1^ i^ I ©® ^UOi mm^M^ 1 k"""^-^^**^ 1^ mtMfi mj^BQii, 49 ^ P^-^^fepl ^E / 3\ r^H|^RC3^p']j|n~| ^^s *^f%m'"^ ^P^l^ Mm s-mrM ^ — ^^SLj Fig". I. Demonstration Apparatus for Klectricity VII. The number of schools generously supplied with appara- tus is rapidly increasing. VIII. As a rule the College Entrance Board Course meets with favor in the smaller as well as in the larger schools. IX. The majority of teachers of Physics have from 10 to 20 recitations per week on other topics than Physics. Twenty- three of the 183 replying have over 30 periods per week besides Physics, and one teacher reports 59 periods weekly besides Physics. X. There is a marked tendency to specialization among the Physics teachers. That about one-half the teachers reporting on this question have had special training is certainl}' encouraging. METHODS OF INSTRUCTION. Successful work in Physics requires a definite plan of instruc- tion. It is. assumed that the teacher will outline ahead not only his daily work, but that early in each year he wiU formulate what he hopes to accomplish with the classes and equipment at his disposal. The following statement of methods, which is largely a summary of an elaborate report on Methods of Instruc- tion in Physics, published by this Association in 1900 may be helpful. The principal methods of teaching Physics are these: — I. The Lecture and Demonstration method which may be regarded as the presentation of the subject to the class by the teacher with such experimental illustrations as may be desirable. By this method the teacher shotild cover the subject in outline, showing the relation of physics to the various practical affairs of every day life, and drawing illustrations so far as possible from local industries. The lecture should be so conducted as to awaken interest and to present important facts and principles in a forcible manner. The experiments should be for purposes of illustration and em- phasis, and shotild be so carefully prepared that they will not fail to show the principle intended. Pupils should take notes on the demonstration experiments under the direction 'of the teacher. The teacher should give instruction as to the best method of taking notes. The lecture is usually more valuable if informal and appealing personally to the pupils. An outline of the topics covered by the lecture should be given the pupil either from the blackboard or by the use of printed or hectographed forms. II. The Recitation method, which is the presentation of the subject to the teacher by the pupil, with such discussion — deve- loped largely by questions and answers — as the occasion may demand. The recitation, which forms a ready means of testing the pro- gress of the pupil and ascertaining his needs, should be mainly by topics, with free use of the text book and reference library. To secure clear comprehension of a topic nothing can take the place of the quiz. It is essential to the recitation. The teacher should also encourage questioning on the part of pupils but should never allow quibbling. Assignment of daily stud)^ should be by topic. III. The Laboratory method includes the experimental work on the part of the pupil, under the supervision of the teacher, elucidating important facts and principles. Fig. 2. Apparatus for Experiments in Mechanics The laboratory work should seek to develop the pupil's power of observation and discrimination; to teach him to work system- atically; to follow intelligently directions whether oral or written; to reason correctly and to record the results of his work in good English, with clearness, neatness and simplicity. If properly conducted it will make him somewhat acquainted with mechan- ical processes, and will develop self-reliance coupled with an ap- preciation of his own limitations and a due respect for the work and attainments of others. Both teacher and pupil should be thoroughly prepared for the work to be done. Laboratory work should be partly qualitative, but largely quantitative, the relative amount of the two depending upon the maturity of the pupils. If the school offers an elementary and an advanced course, the first should be mostly qualitative, and the second quantitative. In no case shoiold a high degree of accuracy be expected. It is economy of time and energy for all pupils to w.ork simul- taneously upon the same problem. A longer allotment of time than the usual recitation period is desirable for some laboratory exercises. The pupil should keep a laboratory note book, which shoiild contain a concise statement of, — (1) The problem to be solved. (2) Apparatus and material used, and generally a sketch of the apparatus used. (3) Method of work followed. (4) Measurements and data neatly tabulated. (5) Computations. (6) Results noted, — conclusions or inferences. Of these three methods of instruction no one should be domin- ant, but all should be closely related, and supplementary to each other. The amount of time given to each method and the order of sequence raxist be determined by local conditions and the matur- ity of the pupils, as well as by the training of the teacher and the equipment of the school. With small classes the best restilts may often be secured without too conspicuous separation of the methods used. It is assumed that the above methods will be re-inforced by brief and frequent written tests and also by formal examinations at less frequent intervals. Physics is largely a mathematical subject. A few problems illustrating the principles of the lesson, taken from the text-book or other source, and made a part of the daily assignment for home work, give a tangible object for study. Great care must be taken that these problems are not too difficult mathematically, else the labor of computation will obscure the principle of Physics involved. The following helpful devices should also be used as far as pos- sible : Lantern view exhibitions. Reports upon topies looked up in tlie libran' or in eurrent literature. Visits to factories and power plants with reports. Pupils acting as teachers in experimental demonstrations. Discussions between pupils under supervision of the teacher. Students clubs, for more extended investigation. Fig-. 3. Apparatus for Experiinent.s in Heat Paramount to all detailed methods of instruction is the spirit of the teacher in his work and his attitude of sympathy with the class. The teacher must put himself in the place of the pupil and approach every subject from that standpoint. An appeal to the pupils' own experiences or previous knowledge concerning some application of each principle is an open door to interest and profitable instruction. RECOMMENDATIONS. This committee makes the following recommendations to the schools for which this report is intended: — I. Physics should be given a place in every coiorse of study in the secondary school: (1) because of its value as a disciplin- ary study; (2) because of the useful information which it imparts concerning the affairs of every day life. II. With the rapidly increasing number of new text-books, each school should select that best adapted to its own needs and limitations, rather than the most comprehensive book, which may be suited only to the large city school. The place of the subject, in the curriculum should influence the choice of the proper book to use. III. This committee wotild recommend that well plaimed individual laboratory work constitute an important part of the course in Physics. It is also very desirable that laboratory periods should not be less than 45 minutes each. IV. The laboratory experiments performed by pupUs should be supplemented by many illustrative experiments, largely qualitative, performed by the teacher before the class. V. If the number of pupils taking Physics in a school is very small and it is financially impossible to offer an individual labor- atory coiu-se, the laboratory and recitation work may be combined and much benefit derived from a single set of pupil's apparatus used by a small group of pupils. Every pupil should take a care- ful, individual record of the experiments performed by the group. The teacher's personal supervision of such exercises, accompanied by suitable questions may make it valuable both as an exercise in Physics and in the personal influence of the teacher on his pupils. VI. While every teacher should choose those experiments which meet his own needs and available apparatus, this committee recommends the following thirty experiments, selected from the options which the college Entrance Examinations Board adopted in 1909, as giving a satisfactory return for a moderate expendi- ture of time and money. Exp. Nos. 1, 2, 3, 4, 6, 10, 11, 12, 14, 15, 16, 18, 19, 21, 22, 25, 26, 28, 31, 32, 33, 34, 36, 40, 42, 43, 44, 46, 48, 49. In addition to this list as many more experi- ments may be performed as time and apparatus permit. VII. In the purchase of apparatus this committee strongly recommends that each school adopt some consistent general plan of piircJiase, looking toward an equipment somewhat be- 3'ond its present needs. The yearly purchases should be devoted to securing apparatus of good quality, of permanent value, as parts of such complete equipment, even though deficient for a time in some departments. Home-made apparatus is cheap and in- structi\'e. Pieces made by local mechanics are frequently very efficient and cost less than the product of the apparatus dealers. Much apparatus can be imported at a considerable saAdng, through the regular American dealers. This is especially true of expen- sive apparatus and chemical glassware. Fig. ,4. Apparatus for p^xperinient.s in Light Teachers of Physics should be supplied with ordinary' tools and have special time allowed them for the preparation of apparatus for their work. Every teacher of science will do well to keep on file the illustrated catalogues of the large apparatus dealers, which are sent without charge (List of dealers given in appendix). The catalogues of many manufacturers of steam and gasoline engines, heating systems, electrical devices, electric motors, etc., are always helpful. VIII. For the convenience of reference, this committee has prepared two lists of apparatus, which arc giA'cn at the end of this report. One of these lists is devoted to apparatus for the pupils' laboratory work, and is required for the thirty' experi- ments mentioned in this rejjort, while the other includes the more 13 important pieces needed for the teacher's demonstration of topics mentioned in the College Entrance Board list of topics. The list of apparatus for pupils' use is arranged to show the cost of an equipment for a class of ten pupils. In a few cases with expensive apparatus, it is assiraied that classes will work in groups of two or more pupils. For schools having classes larger than ten, the amount of apparatus should be increased in proportion to the number of pupils. In all cases, there should be added to the pupils' apparatus, as large an amoumt of the teacher's demonstration apparatus, as funds will permit. IX. This committee wishes to call especial attention to the statement of the College Entrance Examination Board concern- ing the course in Physics. Emphasis is placed, first on "the study of one standard text-book," etc.; second, "Instruction by lecture table demonstration,"; third, "Individual laboratory work." The thirty experiments should require from one-fourth to one- third the entire time given to the subject. While indi-vddual laboratory work is very important it must not assume undue prominence in time and efEort at the sacrifice of the other means of instruction. Experience has shown that the coiu-se in Physics should occupy not less than a full year's work of five rec'tations per week. The course should come in the junior or senior year of the High School curriculum. It is very desirable that pupils should have had a previous course in Elementary Algebra and Geometry. The examination questions set by the College Entrance Ex- amination Board as well as the questions set by some of the colleges should always be at hand as suggestive of the method of instruction which advanced institutions expect. X. As a valuable aid to profitable study of Physics, the com- mittee would recommend that a few careftilly selected reference books be kept at all times in the Physics room, and that assign- ments of supplementary topics be made a part of the work. Frequent reference to the scientific magazines will also be val- uable. Several of the better text-books of secondary school grade, which present the topics from slightly different points of \'iew always interest and prove helpful to classes. 14 XL Assuming that the vahie of scientific study is recognized, the importance of Ph^'sics, (1) As a basis for other science work; (2) As a means of acquainting young people with the applica- tion of nature's laws to modem appliances; (3) As a direct appli- Fig. 5 Apparatus for Experiments iu FJectricity. cation of high school mathematics ; entitle it to a foremost place in the course of study which our schools should give. Teachers of science and principals can not too strongly urge both college preparatory students as well as all whose school life ends with the high school, to include the subject Physics in their course of study. JOHN W. HUTCHINS, Chairman, High School, Maiden, Mass. CALVIN H. ANDREWS, South High School, Worcester, Mass. N. HENRY BLACK, Roxbury Latin School, Boston, Mass. CLEMENT C. HYDE. High School, Hartforil, Conn. FRANK A. WATERMAN, Smith College, Northainpton, Mass. 15 Apparatus for a Class of Ten Pupils performing the thirty experiments in this list. These articles may be purchased from apparatus dealers at approximately the prices quoted. Articles marked with an asterisk (*) can usually be secured locally to good advantage. The experiments are numbered as in the list adopted by the College Entrance Examination Board in 1909. Exp. 1. Weight of unit volttme of a substance, prism or cylinder. 10 Harvard Trip Scales or other equal arm platform balances $60 . 00 10 Sets Metric weights in block, 500 grams to 1 gram, or 10 sets Hook weights in block 500 grams to 1 gram, made by C. H. Stoelting Co., at $2.00 each $20.00 1 doz. Metric rules, maple, 30 cm .40 or Keuffel and Esser boxwood, 30 cm. rules (8872) .75 *Rectangular blocks and cyUnders Exp. 2. Principle of Archimedes. 10 Overflow cans $4.50 10 Equal arm platform balances, — (Listed Exp. 1) 10 Beakers (250 c.c.) or tumblers .50 * Solids denser than water, weighing between 100 g- and 250 g. Use stone, coal, etc * Solids less dense than water. Use blocks of wood, apples. . . . If preferred use the spring balances, Usted in Exp. 12, substitut- ing for the beakers or tumblers, 10 catchbuckets, price 40c each. Exp. 3. specific gravity of a solid body that will sink in water. 10 Equal arm platform balances and weights. — (Listed Exp. 1) 10 Glass battery jars, capacity not less than 1 quart, (4" x 6 ) . . $1.80 * 10 Balance stands, home made, see illustration Fig. 7 * Solids weighing 100 g. to 250 g., — porcelain, solid glass stopper, pieces metal, stones, sulphur Exp. 4. Specific gravity of a liquid, two methods (bottle and displacement methods). 10 Platform balances and weights, — (Listed Exp. 1) 10 Specific gravity bottles. Use ordinary two ounce wide mouth bottles, with solid glass stoppers , $1 . 00 * Liquids of various densities, — Salt water, milk, denatured alcohol, kerosene By displacement method, — 10 Glass jars, capacity not less than 1 quart, — (Listed Exp. 3) * 10 Small pieces of glass or porcelain, weighing not less than 100 g. i6 Exp. 6. Boyle's Law. 5 Boyle's Law tubes, funnel top, large bore, thick walls $5.00 * Use laboratory supports (Fig. 6) to hold tube 5 Meter sticks, maple, — (Listed Exp. 10) 5 lbs. Mercury. This mercury must be very clean. Mercury $4.50 may be cleaned by thorough agitation with water 1 Mercury barometer, metric, adjustable $6.00 Exp. 10. The straight lever, principle of moments. 10 Meter sticks with fulcrum support. See illustration Fig. 10. . $2 . 50 * 10 Laboratory supports, — Illustration, Fig. 10 Weights (Hook weights are convenient), — Listed Exp. 1 Exp. 11. Center of gravity and weight of a lever. 10 Meter sticks, — (Listed Exp. 10) - * 10 Wood prisms, triangular, each face 2 inches x 1 inch Load one end of meter stick with some weight to destroy symmetry, or use as lever the upright shown in Fig. 8. Exp. 12. Parallelogram of forces. 15 Spring balances, metric 250 gram flat back $9.00 10 Metric rules, 30 cm. (Listed Exp. 1) 10 Rectangular blocks, — (Listed Exp. 1) Exp. 14. CoefiScient of friction between solid bodies, on a level and by sliding on an incline. * 10 Smooth boards, 24 x 6 x 7-8 inches 10 Smooth blocks, — (Listed Exp. 1.) 10 Platform balances and weights, — (Listed Exp. 1) 10 Spring balances, 250 g. — (Listed Exp. 2) * Large sheets of paper Exp. 15. Efficiency test of some elementary machine, either puUey, inclined plane, or wheel and axle. 10 Single pulleys $2,25 10 Double pulleys $4.00 [Pressed steel laboratory pulleys are recommended] Weights, brass, — (Listed Exp. 1) [Hook weights are desirable] * 10 Laboratory supports as shown in the illustration, — Fig. 6 . . 20 2inchironclamps,— SeeFig. 6 $3.50 100ft. small braided cotton cord [This should be stretched before using.] Exp. 16. Laws of the pendulum. 10 Pendulum balls, iron, 1 inch diameter, drilled .80 10 Meter sticks, — (Listed Exp. 10) 10 Supports, — (Listed Exp. 15) 17 Balance Stand and Laboratory Support (Figs. 6, 7, 8, 9, 10.) This is an inexpensive, home- made substitute for iron svipports. Dimensions of tlie balance stand are: — top, 1.5 x 10 x 3-4 inehes; sides, 14 X 2 X 1-2 inches: ends, 8 X 2 x 1-2 inches: legs, 10 x 1 x 1 inches; upright rod, 42 x 1 x 1 inches: cross arm on upright, 7x1x1 inches. The top anil sides of the table may be of any kind of wood, but the legs and support should be of hardwood, preferably ash. The parts should be firmly screwed together. Either iron screw clamps or two small bolts with thumb nuts may be used to fasten the support arm in position. Fig. 6 shows the upright rod clamped to one leg of the inverted table, as a support for the pen- dulum, and the pulley. Adjust- ments of the length of the pen- dulum are made by turning the spool. The hole in the sup- port through which the thread passes may be made with a hot needle if a Xo. 64 drill is not at hand. This support may be used to hold the Bovle's law tube (Exp. 6). Fig. 8 shows the support arm used as the centre of gravity lever (Exp. 11.) By attaching the weights as illustrated, the centre of gravity is kept below the point of support, permitting accurate balancing. With screws, screw eyes, spools and wooden bars many attach- ments can be made to the stand, which are not indicated in the cuts and which will much extend its usefulness. Fig. 6. i8 This shows the bal- ance table in use for finding specific gravi- ty and in studying the buoyant force of water. Exp. 2 and Exp. 3. Fig- 7- Fig. 8. Upright support used in studying the influence of the weight of a lever. Kxp. 11. This shows a means of support- ing a meter stick as an equal arm lever in stable equilibrium. Use either a metal or hard wood block screwed to the meter stick and a loosely-fitting wire nail as a ful- crum. XcX" CZ>^ 9 50 I Fig. 9. 19 Exp. 18. The mercury thermometer: relation between pressure of steam and its temperature. 10 Copper boilers and burners (Apparatus A) $22 . 50 10 Chemical thermometers enclosed scale (-10° C. ) to (1 10° C. ) 3 . 50 * 10 Mercury pressure gauges 2 . 50 10 Screw pinch cocks 1 . 20 25 ft. Rubber tubing, 1-4 inch 2.50 1 Barometer, — (Listed Exp. 6) 5 ft. 3-16 inch Rubber tubing for connections .40 [If illuminating gas is not available, some form of alcohol lamp may be used to supply heat.] Exp. 19. Linear expansion of a solid. 10 Sets linear expansion apparatus S15 . 00 Hall's form made by Cambridge Bot. Supply Co., or Cowen's to form, made by L. E. Knott App. Co 30.00 10 Thermometers, — (Listed Exp. 18) 10 Copper boilers and burners, — (Listed Exp. 18) 10 Meter sticks, — (Listed Exp. 6) Exp. 21. Increase of volume of a gas heated at con- stant pressure. *10 Straight glass tubes containing dry air, with mercury seal, to be used vertically $15 . 00 To njake: — Use Jena glass tubing, 6 m.m. outside diameter, and 1 m.m. inside diameter. 10 Chemical thermometers, — (Listed Exp. 18) 10 Meter sticks, — (Listed Exp. 10) 10 Copper boilers and burners, — (Listed Exp. 18) * 1 common water pail may be used to hold the ice and snow, while cooling the enclosed air columns. Exp. 22. Heat of fusion of ice. 10 Calorimeters $4. 50 [Nickel plated overflow cans, listed in Exp. 2, may be used.] 10 Thermometers, — (Listed Exp. 18) 10 Platform balances and weights, — (Listed Exp. 1) * 1 tea kettle for heating water Exp. 25. Determination of the dew point. 10 Calorimeters, — (Listed Exp. 22) 10 Thermometers, — (Listed Exp. 18) .- ; Ice and salt. Exp. 26. Specific heat of a solid. 10 Calorimeters, — (Listed Exp. 22) 10 Thermometers — (Listed Exp. 18) 10 Platform balances and weights, — (Listed Exp. 1) 10 Copper boilers and burners, — (Listed Exp. 18) 10 lbs. Lead shot, or metal blocks of aluminum, brass, or copper . $1 . 00 to 5.00 Kig, 10. A meter stick in position as a lever of tiie third order. Attachment to meter sUck shown in Fig. 9 used to support lever on the inverted table leg. Exp. 28. Wave length of sound. 10 Tuning forks, A 435 $10.00 10 Meter sticks, — (Listed Exp. 10) 10 Glass tubes, 13 inches long, not less than three-fourths inches in diameter, inside 10 Battery jars, — (Listed Exp. 3) Use battery jars and tube to vary the column of air as in illustration. Fig. 11 Fig II. Apparatus for measuring the wave length of sound. Exp. 31. Images in a plane mirror. 10 Mirrors, thin glass about 15 cm. x 3 cm $1 .00 10 Metric rules (30 cm.) (Listed Exp. 1) 10 Blocks for support, — (Listed Exp. 1) 10 Paper protractors .80 Exp. 32. Images formed by a convex mirror. 10 Cylindrical mirrors, nickel-plated $4.50 10 Metric rules, — (Listed Exp. 1 ) Exp. 33. Images formed by a concave mirror. 10 cyUndrical mirrors, nickel -plated,— (Listed Exp. 32) 10 metric rules, 30 cm., — (Listed Exp. 1) Exp. 34. Index of refraction of glass. 10 Glass refraction plates, (7.5 cm. x 10 cm.) $2 . 50 10 Metric rules, — (30 cm.), — (Listed Exp. 1) Exp. 36. Focal length and conjugate foci of a converg- ing lens. 10 Converging lenses, 12 cm. focus $.80 10 Lens holders 1 . 50 10 Screen holders .90 10 Meter sticks, — (Listed Exp. 10) * 20 Support blocks for meter sticks * Candles * 10 pieces Wire gauze about 5 cm. square, to be used as objects. 22 Exp. 40. Study of magnetic field. 10 Bar magnets, 15 cm $2.00 1 lb. Iron filings, fine .20 1 doz. Tracing compasses, about 1-2 inch diameter 1.20 Exp. 42. Study of a single fluid voltaic cell. 10 Glass tumblers (heavy) $ . 50 10 Zinc plate elements .60 10 Copper plate elements .60 9 lbs. Sulphuric acid, coric .55 1 lb. Mercury .90 10 Simple galvanoscopes with compasses 25 . 00 as furnished by Gaertner & Co. — H.-2801+H. 2601 or by Central Scientific Co.,— 2401+1765 [The frame may be made locally]. Fig. 12. A simple galvanoscope. Exp. 43. Study of a two fluid voltaic cell. 10 Daniell cells, consisting of: — 10 Battery jars, — (Listed Exp. 3) 10 Porous cups, 2 inches x 4 inches $1 . 50 10 Copper plates, 4 inches x 4 inches 1 .25 10 Zinc pencils 1 . 75 10 Galvanoscopes, — (Listed Exp. 42) 10 Platform balances, — (Listed Exp. 1) 5 lbs. Copper sulphate, crystal .60 Sulphuric acid, — (Listed Exp. 42) Exp. 44. Magnetic effect of an electric current. 10 Daniell cells,— (Listed Exp. 43) 10 Tracing compasses, — (Listed Exp. 40) * 10 Electromagnets, various types of local make Exp. 46. Laws of electrical resistance of wires : various lengths, cross section, and in parallel. [This experiment should follow Exp. 48 and the resistances should be measured by the bridge method. Pupils work in groups of two.] 10 Daniell cells,— (Listed Exp. 43) 5 Wheatstone's bridges, — (Listed Exp. 48) 5 D'Arsonval galvanometers, — (Listed Exp. 48) 5 Known resistance coils, 5 ohms, — '(Listed Exp. 48) 5 Known resistance coils, 10 ohms, — (Listed Exp. 48) 1-2 lb. Copper wire. No. 30, double cotton, to be cut in 10 meter lengths $1 .00 1-2 lb. German silver wire. No. 24, double cotton 1.40 1-4 lb. German silver wire. No. 30, double cotton 1 . 30 [The G. S. wire to be cut in 2 meter lengths] 23 Exp. 48. Resistance measured by Wheatstone's bridge. [Pupils work in groups of two.] 10 Dry cells,— (Listed Exp. 49) 5 Wheatstone's bridges, slide wire form , $15.00 5 D'Arsonval galvanometers 12. 50 [It is safer to use this galvanometer shunted, or else use the gal- vanometer mentioned in Exp. 42 while making the prelim- inary examination of an unknown resistance.] 5 5-ohm Resistance coils 2 . 50 5 10-ohm Resistance coils 2 . 50 [These may be obtained from W. & L. E. Gurley, Troy, N.Y.] 5 pieces German silver wire. No. 24, about two meters long .... Exp. 49. Battery resistance — combination of cells. [Pupils work in groups of two]. 10 Daniell cells, — (Listed Exp. 43) or 10 Dry cells $3.00 10 Simple galvanoscopes with compasses, — (Listed Exp. 42 ) . . . 5 10-ohm Resistance coils, — (Listed Exp. 48) mWi^ FIRST METHOD Weight Empty Bottle Weight Bottle Filled with Cu. S(^ S<:lution . Weight Bottle filUd with Woter Weijht CiiSCV Solution In Bottle Weight t^O in Bottle SPECIFIC GRflVlTT " CuSQ, Weight fiiSC^ .123.3 .£0fe5 . la-l.GS _ 83.2 . 71.35 _ 1.16 j