Work and Play in Girls' Schools / By Three Head Mistresses

by Dorothea Beale; J. F. Dove; Lucy Helen Muriel Soulsby

Even where no laboratory class is taken, the teacher can still take opportunities of convincing the children that experiments can be performed by themselves as well as by their class-teacher; they enjoy being called up to perform an experiment in class, and will, if they have any taste for the subject, take an interest in repeating any possible ones at home; they can convince themselves of air-pressure by private experiment with syringes, siphons, and inverted tumblers, or can find centres of gravity, or experiment with sounding strings of various lengths, but of course such desultory experiments, followed by no careful writing out of results, do not give very valuable training in scientific accuracy.

Diagrams.I would insist also on the importance of requiring children from the first to illustrate their work by diagrams; a little time is well spent in criticising these, and in showing how they might be improved. Very neat and serviceable diagrams may be produced even by children with no natural taste for drawing, but they need to be shown how to work, and perhaps to have the lines of a diagram suggested to them at first by a rough blackboard sketch, or it may not occur to them that a few simple lines will show all that is necessary better than a would-be realistic sketch of apparatus, with impossible perspective and smudgy shading.

Course of electricity and magnetism.I pass on now to somewhat higher classes. With pupils whose average age is about fifteen, some one or two of the branches of physics may be taken more in detail. Suppose electricity and magnetism to be chosen, the aim throughout the course should be so to impart elementary ideas that they may be a real help and not a hindrance to any future effort to take in modern views of electricity. To this end attention should from the very first be directed to the electric or magnetic “field” about any charged or magnetised body and not exclusively concentrated upon that body itself, and the pupils should be accustomed to attribute the motions in such fields not to the “action at a distance” of a charge, a pole, or a wire carrying a current, but to the special condition of the medium immediately around the moving body. The idea of a magnetic field is more readily grasped by beginners than the corresponding idea in electrostatics, owing to the ease with which the field may be mapped to the eye by means of iron filings, or by marking down successive positions of a tiny magnetic needle; it seems to me, therefore, well to begin with the study of magnetism, rather than, as is common in text-books, with that of statical electricity. From magnetism the more natural transition is to current electricity, and it will be found a good plan to take the subjects in this order, passing from the magnetic fields which surround permanent steel magnets to those which are found to exist in the neighbourhood of a wire whose ends have been joined to plates of zinc and copper immersed in a vessel of dilute acid. The existence of such fields will be proved by the magnetisation of iron round which the wire is coiled, and by the motion of permanent magnets near which it is held, and the direction of the lines of force will be inferred from the direction of such motion. The existence of the magnetic field established, the term “current of electricity” may be introduced; the children will readily understand that it arose from the idea that it was something flowing through the wire which gave it such strange properties, and that whether this is the case or not, there is a practical convenience in retaining the old terms.

Some of the practical applications of the magnetic effects of currents may now be explained, e.g., the electric telegraph and electric bells, and the use of a galvanometer as a current indicator. Simple experiments on the induction of currents by motion of magnets, or starting and stopping of currents may follow, it being carefully pointed out that the one essential for such induction in a coil is some change in the magnetic field in which it lies. The principle of dynamos readily follows. The heating and decomposing effects of electric currents may next be considered with their practical applications to electric lighting, and electro-plating respectively, and the attention of the children should be directed to the energy appearing as heat or as chemical separation in the two cases. If they have gone through the preliminary course they will know enough of the conservation of energy to look for the disappearance of energy in some other form, and the chemical action in the battery may now be pointed out. Some explanation of “polarisation” and of the need for more complicated forms of battery than the simple voltaic cell may be given.

Lessons on statical electricity will end the course; they may be connected with the preceding lessons by first speaking of the discharge of a Leyden jar, and that between the knobs of an induction machine as instantaneous “currents,” and going on to the state of affairs in the medium between the knobs or coatings when they are not sufficiently near for the discharge to take place; this will be made clear by going back to earliest facts known about electricity and following the ordinary course of electrostatic experiments.

Heat and light.Should “heat and light” be chosen instead of electricity for this year’s course, the mode of treating the subject must depend very much on the mathematical advancement of the pupils. It is probable that their knowledge will not exceed the first two books of Euclid, and algebra to simple equations, and it will therefore not carry them very far in the treatment of geometrical optics; it will enable the laws of reflection to be intelligibly explained, and the position of the image in a plane mirror to be determined (the law of refraction may also be made clear, as the children can easily be made to understand the meaning of the term “sine”), but formulæ connected with mirrors and lenses should be left to a later stage, the changes in size and position of the image formed by a curved mirror or a lens being determined experimentally and not by calculation. A general explanation of the action of optical instruments, telescope, microscope, spectacles, etc., can be given, without exact calculations, and illustrated either by carefully drawn diagrams, or by models with lenses of cardboard and rays represented by strings. The interest of lectures on dispersion and the spectrum is greatly increased if they can be illustrated by lantern experiments. The subject of heat lends itself better to non-mathematical treatment, and is specially good for practical work by the pupils themselves.

Work of senior classes.The work of senior classes, i.e., girls of seventeen or over, depends so much upon circumstances, such as their previous training, their mathematical knowledge, etc., that it is difficult to say much to the point about it, but a word may be added on a very common fault of such classes, a tendency to rely too much on their teacher and their notes of lectures, and to read and think too little for themselves. Independent reading.The practical work, which is an essential for such classes, does much to encourage self-reliance, but besides this they should from time to time be given some reading to do on points which have not been previously made clear in lectures; difficulties met with in the reading should be brought up at the next lesson, when the teacher will either solve them or put the pupil in the way of doing so for herself. This kind of work takes time, and is therefore apt to be crowded out from a full time-table, but it is worth an effort to find a place for it.

LIST OF SOME BOOKS USEFUL FOR TEACHERS.

I. Practical Physics.

For Beginners—