If the plant is too large for the mounting sheet, cut out the central part, and use the root, lower leaves, upper leaves, and flower. If the root is very thick, cut slices lengthwise off the sides so as to reduce it to a flat form that is not too bulky.
Before the plant has had time to wither, spread it out flat on a sheet of paper and spread another sheet over it, taking care to straighten the leaves and flower out. Blotting-paper is preferable, but any soft paper that will absorb moisture will make a very good subst.i.tute.
~Pressing and drying.~--Place several sheets of paper above and below the specimen. Any number of specimens prepared as described in the last paragraph may be placed in a pile, one over another, resting on the floor or on a table. Place on top of the pile a board which is large enough to cover the surface of the pile, and on the board place a weight of about fifteen pounds of bricks, or other convenient material. A box containing sand, stones, or coal may be used in place of the board and weights. The weight prevents the shrivelling and distortion of the plants.
To prevent discoloration and mildewing of the plants, the papers around them must be changed at the end of the following successive intervals: two days, three days, five days, one week, etc., until they are quite dry. The length of time required for pressing and drying depends upon the quant.i.ty of sap in the plants and also upon the dryness or humidity of the atmosphere.
~Mounting.~--When dry, the specimens are mounted on sheets of heavy white paper. These sheets are cut to a standard size, eleven inches by fourteen inches, or sheets of half this size, namely, seven inches by eleven inches; are permissible. The best method of attaching the plant to the sheet is by pasting narrow strips of gummed paper across the plant in such positions as will serve to hold all parts of it in position.
~Labelling.~--The name of the specimen, the date of collection, the place from which collected, and the name of the collector are to be neatly written in a column in the lower right-hand corner of the sheet. Printed labels which are pasted on this corner of the sheet are also used.
Collections of leaves may be prepared by the same process as that given for plants. Leaves will retain their autumn tints if their surface is covered with varnish or paraffin, which will prevent the admission of air.
To cover with paraffin dip the leaf for a moment into melted paraffin.
CHAPTER II
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 superst.i.tion, 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 a.s.sist 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 cla.s.ses 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 cla.s.s 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.