Chapter 16

PHYSICAL SCIENCE PHASE OF NATURE STUDY

INSTRUCTIONS AND GENERAL METHOD

The preceding portions of this Manual dealt with living things. There is another phase of Nature Study which has a more direct relation to the physical sciences, Chemistry and Physics, two subjects that are essentially experimental in their methods.

Although the lessons that follow are grouped in one portion of this book, the teacher should understand that he is to introduce them into his work as the occasion demands. They may be used to throw light on other parts of the school work. The experimental method is somewhat advanced for young children, hence no lessons are outlined for Forms I and II. In ungraded schools, Forms III and IV may be combined for the subject. It will be found most convenient to take this portion of the Nature Study during the winter months.

VALUE OF SUCH LESSONS

1. They are _interesting_, hence there is attention. The senses must be alert, hence pupils are trained to observe accurately.

2. After the experiment comes the inference, hence reasoning powers are developed.

3. They enable the teacher to make exceedingly _concrete_ some very difficult abstract principles.

4. They can be _correlated_ with a large number of other subjects and made to have a beneficial influence on the whole of the school work.

5. The great advance that is being made in all useful inventions to-day is largely due to the study of the physical sciences. Many boys and girls (seventy-five per cent.) never attend the High School. The Elementary School owes them a taste at least of these sciences that have such a bearing on their lives, that have surrounded them with so many mechanical contrivances for their comfort and convenience, and that explain so many common natural phenomena. Give a boy a taste for experimental science, and there is some chance that after leaving school he will not throw aside his studies to subsist intellectually on the newspaper, but that he will continue to investigate for himself, and make himself a well-informed man, an influential man in his section. The Elementary School must aim at fitting the boys and girls for life.

6. The advent of the experiment marks the downfall of superstition, prejudice, and reliance on authority and tradition. To lead a child to think for himself is a great achievement.

7. The use of the experiment in gaining knowledge will result in a cautiousness in accepting statements and making decisions.

CONDITIONS UNDER WHICH EXPERIMENTS SHOULD BE PERFORMED

1. They should be introduced into the school work naturally, as answers to questions which arise either in the regular course of the work or from suggestions made by the teacher at appropriate times.

2. As far as possible, the pupils should assist in performing the experiment. In small rural schools the scarcity of apparatus will necessitate the teacher's doing most of the work. In Form V classes and Continuation Schools the pupils may do the experiments individually.

3. The bearing of an experiment is not always evident; the teacher must be ready with judicious questions to lead the class to the proper conclusions.

4. The pupils must be acquainted with all the apparatus used. They must know what the teacher is doing and must be near enough to see the result.

5. A problem may be suggested, and a few days allowed for the pupils to think out a means of solution. If they invent and make their own apparatus, so much the better.

6. Whenever possible, the experiment should be applied to some natural phenomenon or everyday occurrence.

CORRELATIONS OF PHYSICAL SCIENCE PHASE

Geography.--The value of Physical Science in the Elementary School is largely due to the light it throws on geographical data. Numerous examples will appear in the succeeding pages.

Hygiene.--Experiments in carbon dioxide, oxygen, air, water, sound, and light, are absolutely necessary, if the children are to grasp with any degree of clearness the principles of respiration and ventilation, and the phenomena of hearing and seeing.

Manual Training.--Many pieces of apparatus may be made by the boys in their work with wood or iron. Some of the elementary principles of chemistry enable the girls to do their cooking intelligently. A knowledge of some of the principles of machines will help the pupils to understand the tools they may use in any employment.

Drawing.--Careful drawing of the apparatus used helps to fix the experiment in the mind and at the same time gives practice in art.

Composition.--Pupils must have ideas before they can write. The description of the experiment will make a good composition exercise, oral or written.

LIST OF REFERENCE BOOKS AND BULLETINS

GARDEN AND PLANT STUDY

Bulletins of the Ontario Department of Agriculture, Toronto.

Bulletins of the Dominion Department of Agriculture, Ottawa.

Improvement of School Grounds. Department of Education, Toronto.

Atkinson. First Studies of Plant Life. Ginn & Co. 60 cents.

Bailey. Manual of Gardening. Macmillan Co. $2.00.

Blanchan. Nature's Garden. Doubleday Co. $2.00.

Comstock, A. M. Handbook of Nature Study. Comstock Pub. Co. $3.25.

Gray. Field, Forest, and Garden Botany. Amer. Book Co. $1.40.

Green, Louise. Among School Gardens. Charities Pub. Co. $1.25.

Hodge. Nature Study and Life. Ginn & Co. $1.50.

Holtz. Nature Study. Scribners' Sons. $1.50.

Jackson and Dougherty. Agriculture through the Laboratory and School Garden. Judd. $1.50.

James. Agriculture. Appleton & Co. 80 cents.

Keeler. Our Native Trees. Scribners' Sons. $2.00.

Osterhout. Experiments with Plants. Macmillan Co. $1.50.

Parsons. How to Plan the Home Grounds. Doubleday Co. $1.00.

Sergeant. Corn Plants. Houghton, Mifflin Co. 75 cents.

PHYSICAL SCIENCE

Miller. Minerals and How They Occur. The Copp, Clark Co. $1.50.

Milliken and Gale. First Course in Physics. Ginn & Co. $2.00.

Newman. Laboratory Exercises. Ginn & Co. 10c. each.

Remsen. College Chemistry. Am. Pub. Co. $2.50.

Simmons and Syenhouse. Science of Common Life. The Macmillan Company, $1.00.

Woodhull. Home-made Apparatus.

High School Text-books.

ANIMAL STUDY

Bulletin No. 52. Dominion Department of Agriculture, Ottawa.

Bulletin No. 134. Ontario Department of Agriculture, Toronto.

Bulletin No. 161. Ontario Department of Agriculture, Toronto.

Bulletin No. 124. Ontario Department of Agriculture, Toronto.

Reports of Entomological Society of Ontario. Department of Education.

Fishes of Ontario. Nash. Department of Education.

Bailey and Coleman. First Course in Biology. The Macmillan Company. $1.25.

Buchanan. Senior Country Reader. The Macmillan Company. 40 cents.

Chapman. Bird Life. Appleton. $2.00.

Crawford. Guide to Nature Study. The Copp, Clark Co. 90 cents.

Dearness. How to Teach the Nature Study Course. The Copp, Clark Co. 60 cents.

Jordan and Kellogg. Animal Life. Appleton & Co. $1.20.

Kellogg. Elementary Zoology. Holt & Co. $1.35.

Reed. Bird Guide--Parts I and II. Musson Book Co., Toronto. 40 cents each.

Shaler. Domesticated Animals. Scribners' Sons. $2.50.

Silcox and Stevenson. Modern Nature Study. The Macmillan Company. 75 cents.

NOTE.--The bulletins named above are supplied free to schools. Chemical and Physical Apparatus and Entomological Supplies may be obtained from G. M. Hendry Co., Victoria Street, Toronto. Rocks and Minerals may be obtained from the Ward Natural Science establishment, Rochester, or from the Central Scientific Co., Chicago.

PHYSICAL SCIENCE

FORMS III AND IV

DESIRABLE APPARATUS

1 lb. glass tubing in 3 ft. lengths 3/16 in. to 1/4 in. outside diameter. 6 Florence flasks, 4 oz. to 8 oz. $ .50 1 Funnel, 3 in. diameter .10 1 Beaker, 8 oz. .10 1 Evaporating dish .10 3 ft. pure gum rubber tubing 1/8 in. inside .25 1/2 sq. foot thin sheet rubber .20 1 doz. test-tubes 6 in. by 5/8 in. .20 1/2 doz. test-tubes 6 in. by 7/8 in. .10 Capillary glass tubing, 3 sizes .10 2 rubber stoppers No. 2, one hole 1 " " " 4, " " 1 " " " 7, two holes .30 2 watch glasses .10 Ball and ring 1.00 2 Dry cells .60 2 Bar magnets .50 1 Chemical thermometer 212 deg. F. to 0 deg. F. .40 1 Spirit-lamp .20 1 Retort, 4 oz. stoppered .15 Wax candles .10 Retort stand of iron, two rings .85 1 Thistle tube .10 Common corks, assorted .10 Filter paper 5 in. diameter .05 Test-tube holder .10 Test-tube rack .10 Test-tube cleaner .10 1 piece glass tubing 30 in. long, 1/4 in. inside, for barometer .20 1 clamp for closing rubber tube .10 Covered copper wire .10 Small compass .50 Glass model of common pump 1.00 Globe for weighing air 2.50 Small piece of platinum foil, 1/2 in. by 2 in. .25 Glass prism 60 .50 Tuning fork 4-1/2 in. .50 Electric bell .50 Motor (Ajax) 1.50 Balance 10.00 Air-pump 15.00 Iron wire gauze .05 Sheet metals, iron, copper, zinc, lead, aluminum .25 2 lamp chimneys, straight ones preferred, at 10c .20 Iron ball, 2 in. in diameter .20 2 dairy thermometers at 15c .30

CHEMICALS

Sulphuric acid, 1 lb. .10 Hydrochloric acid, 8 oz. .10 Nitric acid, 4 oz. .10 Washing soda .05 Sugar .05 Salt .05 Blue vitriol .10 Alum .05 Saltpetre .05 Sulphur .05 Potass. permanganate .05 Lime .05 Plaster-paris .05 Potass. bichromate .10 Methylated spirits, 1 pt. .10 Alcohol, 95% .10 Iodine crystals .10 Mercury, 1 lb. 1.00 Pot. chlorate .15 Manganese dioxide .10 Phosphorus .10 Sweet oil, 2 oz. .10 Benzine, 2 oz. .10

The following tools will be found very valuable: saw, square, plane, brace and bit, knife, hammer, glass cutter, files--round, flat, and triangular.

Where the circumstances will not allow of the purchase of the preceding list, the following apparatus is recommended as sufficient for the performance of a large number of the experiments:

1/2 lb. glass tubing in 3 ft. lengths, 3/16 in. and 1/4 in. outside $ .20 2 Florence flasks, 4 oz. .15 1 Funnel .10 2 ft. pure gum rubber tubing, 1/8 in. inside .15 1/2 doz. test-tubes assorted, 5/8 to 7/8 diameter, 6 in. long .20 2 rubber stoppers, No. 2, one hole .10 1 rubber stopper, No. 4, one hole .10 Expansion of heat apparatus (made at blacksmith's) .10 Common corks, assorted .10 1 chemical thermometer 0 deg. F. to 212 deg. F. .40 1 spirit-lamp, 4 oz. .10 1 thistle tube .10 Covered wire, copper .10

CHEMICALS

Iodine crystals .10 Sulphuric acid, 1 lb. .10 Methylated spirits 1 pt. .20 Alcohol, 95% .10 Mercury, 1/2 lb. .50 Pot. chlorate .15 Manganese dioxide .10

The following may be obtained, for either list, at little or no cost from household stores or home-made sources: washing soda, sugar, salt, ammonia, coal, coke, saltpetre, sulphur, blue vitriol, alum, potass. bichromate, blueing, lime, pickle-jars, wire gauze, candles, wire, sheet metals, test-tube holder and rack, balance, battery cells, horse-shoe magnet, pneumatic trough, lamp chimneys, tin cans, melting spoon, bicycle pump, baking-powder.

For home-made apparatus, consult _Laboratory Exercises in Physics_ by Newman, Ginn & Co., 50c., and Manual on _Manual Training_.

Reference has been made in the preceding experiments to the use of simple and easily contrived apparatus. The more of this the pupils can contrive and make under the direction of the teacher, the more valuable will be the course in Physical Science.

GRENET CELLS

Into a pint gem-jar put water 10 parts, sulphuric acid 1 part, potass, bichromate 1 part. Have jar three quarters full. Cut a piece of board 4 in. square, bore two holes in it, and through the holes thrust two pieces of electric light carbon, 5 in. or 6 in. long. The outer edges of the carbons should not be more than two inches apart. With a saw, cut a slit in the board between the holes and insert a strip of zinc 2 in. by 7 in. previously rubbed over with mercury. Set the three elements in the jar, connect the two carbons to one wire, and the zinc to another.

One cell of this kind will run a small motor, operate a telegraph sounder, make a simple electro-magnet, or ring an electric bell; two cells will decompose water: three will heat a piece of fine iron wire red-hot.

DECOMPOSITION APPARATUS

1. Cut the neck end from a pickle bottle. Get a No. 1 stopper, (rubber) with two holes in it and insert a piece of platinum foil 2 in. by 1/8 in. into each hole so that 1/2 in. projects above and below. Insert a tight plug beside each strip, thus holding it fast and making the stopper watertight. Insert the stopper into the neck of the jar. Pour into the vessel thus formed enough water to cover the platinums, and add a few drops of sulphuric acid. Touch the wires from the battery to the lower ends of the strips. Note bubbles of gas arise from the platinums. These may be collected in test-tubes and found by test to be oxygen and hydrogen.

2. Fasten a strip of platinum 1 in. by 1/8 in. to each wire from the battery and dip these into some acidulated water contained in a tumbler. The decomposition of the water into two gases can be seen, but the gases cannot be collected so readily as in 1 above. Bits of electric light carbon will do instead of platinum if the current is not too weak.

PNEUMATIC TROUGH

When oxygen or other gas is to be collected over water, use a milk pan or similarly shaped vessel.

SPIRIT-LAMP

Use an ink-bottle to contain the alcohol and several strands of string for the wick; make a hole in a piece of tin and draw the wick through; then let the tin rest on the neck of the bottle to support the wick.

BAROMETER

A siphon barometer takes less mercury than a cistern barometer. To the open end of the barometer tube attach a piece of strong rubber tubing 4 in. long and to this a piece of glass tubing 3 in. long. Fill the tube thus formed with mercury to within 3 in. from the top. Holding the short glass tube open end up, turn the long tube closed end up. (A tube of 1/8 in. bore needs only one quarter of the mercury required to fill a tube 1/4 in. bore.)

HYGROMETER

For a hygrometer, suspend two dairy thermometers side by side against the wall, cover the bulb of one with thin muslin, and let the muslin hang down and dip into water in some small vessel placed about three inches below the bulb on a little shelf.

HINTS

To avoid explosions, a spirit-lamp should be kept filled.

Toy rubber balloons answer well for sheet rubber.

Red ink makes good colouring matter.

Make touch-paper by soaking any porous paper in a solution of saltpetre, and drying it.

Instead of bending glass tubes, join them with rubber tubing.

To make a test-tube holder, fold a sheet of paper until it is about half an inch wide and wrap this around the tube.

To bend glass tubing, hold in the flame of the spirit-lamp and rotate between the fingers till it becomes soft and flexible, remove from the flame, and bend.

To break glass tubing, first scratch with a file.

To break glass bottles, make neatly a deep cut with a file, then touch the glass near the cut with a red-hot wire. When a crack appears, move the hot wire and the crack will follow. Several heatings may be necessary.

In the case of a heavy glass bottle, file the cut as before, wrap the bottle with string dipped in alcohol, light it, and after it has burned, plunge the bottle vertically into cold water.

Melted paraffin is good for closing small leaks.

TIME APPORTIONED TO NATURE STUDY

The Nature Study lesson should be given a definite place on the time-table. It is recommended that each class should have at least one lesson of fifteen minutes in length, a week. In addition to this, about five minutes a week should be spent in assigning problems for out-of-door work and in discussing the observations which the pupils have made on problems previously assigned.