The Educational screen (c1922-c1956])

Page 166 The Educational Screen fj, n an tfiE C^Lc aiizoonz Conducted by Wilber Emmert Director Visual Education, State Teachers College, Indiana, Pa. i Models for Enrichment RECENT experiences in supervising elementary science, teaching a survey course in physical science, as well as conducting a course in descriptive astronomy, have brought forceably to my mind the necessity of making and using simple mechanical aids to assist the pupils in gaining correct understandings of some of the many abstract concepts encountered in courses which deal with terrestrial and celestial re- The writer with a few aids for astronomy teaching lationships. This article proposes to indicate how some of the teacher-pupil constructed mechanical aids and commercially made devices can provide lasting memory images and assist in overcoming some of the limitations to learning commonly encountered in the study of the topics mentioned. An underlying concept of perceptual learning is the principle that sensory experiences are necessary for mental activities. Sensory experiences properly con- ditioned result in vivid and lasting memory images. These memory images constitute the building blocks for reflective and constructive thinking. Hence, it is recognized that we can think only in terms of our past experiences; and that we can imagine only with the elements of our past experiences. If the visual-sen- sory aids used in the classroom provide the proper degree of reality, are within the range of the pupil's past experiences, fit in with the objectives of the par- ticular lesson, and are within the range of the intellec- tual maturity of the learner, they will assist in making the abstractions encountered meaningful, and provide memory images for intellectual advancement. Scientists have conceived a whole host of "imaginary" lines, circles, and angles to indicate the relations exist- ing on the terrestrial sphere and the celestial globe. "The equator is an imaginary line passing around the earth midway between the poles, and at right angles to the earth's axis." "The meridian is an imaginary line joining " "The horizon is an imagi- nary line " The globes ,maps, charts, etc.. commonly used in geography work assist in mak- ing these abstract concepts meaningful for the problems of the terrestrial sphere. However, the similar as- tronomical coordinates in the celestial sphere tax the conception of the abstract circles of the celestial sphere, imagination of the pupils. And for most minds a con- crete model is a necessary aid in attaining an adequate conception of the abstract circles of the celestial sphere. The Coelosphere The Coelosphere consists of systems of circles to illustrate the astronomical coordinates of the three systems of circles of the celestial sphere recognized in astronomical work, namely the horizon system, the equator system, and tlie ecliptic system. Commercially made, as in the accompanying illustration, the coelo- sphere sells for $16.00. However such a device can be made by the pupils with no outlay of money, by merely using materials right at hand. It looks compli- cated, but it is really easy to make. A tennis ball can be used to represent the earth (equator, ecliptic. meridians. and parallels of lati- tude marked on with ink), while wire coat hangers can be conveniently shaped to form the circles df the individual systems. Excess wire of the hooks can be snipped off with a pair of pliers. One or two hooks can be straightened out to make the ped- estal for the appa- ratus. This device shows clearly the inter-relation of the different sys- tems of coordinates, as well as their relation to the earth. This is one of the most important bits of appa- ratus the school can secure to assist the pupils in gain- ing clear understandings of the problems connected with the circles of the celestial sphere. The meaning of the concepts embodied in the equinoxes, the celestial equator, the ecliptic, right ascension, declination, etc.. can be easily and effectively demonstrated. Prior to the use of the composite model, the pupils should have the opportunity to construct and use individual models The Coelosphere