Showing papers in "Physics Education in 1982"

Gravity - don't take it for granted!

Abstract: The interviews at the heart of this study were concerned with the concept of force. During the course of the discussions some youngsters felt the need to use the term gravity and were often asked to expand on their meaning of that word. I have suggested that the conceptual frameworks children use can be called `alternative frameworks', which I would describe as their imaginative efforts to explain the world around them. A pupil's own view can often be very different from the traditional physics view and can persist even through A-level and undergraduate work. Some of the frameworks that have been considered in this article have been noted by other researchers, most particularly in the work of Stead and Osborne (1979). Their study is close in spirit, too, since it employs parallel methods and a similar philosophy to the one I have discussed. This is heartening in that it gives an indication of the commonality of the frameworks. The eight frameworks I have described belong to no one pupil, but are composite pictures drawn from many discussions. I have made no attempt to quantify these results as yet, nor to make generalisations about all children's understanding from what is quite a small sample. However, it is difficult not to make some observations which may be of general interest. These frameworks are only accurate to a first approximation - there were many subtle variations within each one. This leads to the conclusion that for any group of pupils there might be as many qualitatively different frameworks as there are children. For instance, some thought gravity was power, that it pushed upwards (particularly on the moon); that it is a form of energy; that it drains energy from things, etc. Happily, there can be sufficient similarities to warrant collection as frameworks. At no point am I suggesting that pupils should understand physics in the same way as a mature physicist does. It would be surprising indeed if all pupils approached the questions with a full `Newtonian gestalt'. The important point is not that they do not understand, but that they understand differently, the emphasis of this article being on the many ways that they try to understand. Barnes (1974) has talked about a `gulf of understanding' between teacher and taught. Physics teachers may have lived with their subject so long that its technical terms and its ways of speaking are all so well known and fluently used that they come to be second nature. Exploring the meanings that children have for these terms may help to bridge the `semantic gap' and allow for more effective teaching of some complex concepts.

Energy and its carriers

Abstract: Reports on the first course of a new physics curriculum developed at the Karlsruhe Institute for the Didactics of Physics (Falk and Herrmann 1977, 1978, 1979, 1981). The entire curriculum begins at the elementary school level with children aged 10-12 and is intended to extend beyond high school and through university studies (Falk and Ruppel 1975, 1976). Energy is introduced as the primary quantity at the very beginning of the course. It is not 'derived' from other seemingly more fundamental quantities such as mass, displacement, velocity and force. However, the course is not an ad hoc construction simply to explain the concept of energy. The essential features of many natural and technological processes can be understood by considering the flow of energy. This is the basic idea underlying the course, and can be restated more completely in terms of the following rule: 'something is happening whenever energy is flowing and a flow of energy is always accompanied by the flow of at least one other substance-like quantity'. The course strategy is designed to make this simple rule obvious by way of numerous examples taken from everyday life. Selected topics are highlighted and they introduce concepts unique to the authors approach. These concepts are presented in the same chronological order as they appear in the course.

Measurement of Refractive Index Using a Michelson Interferometer.

Abstract: The Michelson interferometer has long been a popular piece of equipment in the physics undergraduate laboratory. One possible application is the measurement of the refractive index of a thin parallel-side plate of transparent material of known thickness. (Alternatively, if the refractive index is known, the thickness of the plate may be determined.) This is accomplished by using 'white light' fringes superimposed on monochromatic fringes and is described in standard laboratory manuals (Whittle and Yarwood 1973). The author describes another method for measuring the refractive index using and monochromatic fringes and explains how plates ranging in thickness from a few micrometres to several millimetres may be measured.

Zeroth law of thermodynamics

Abstract: And now we do turn to a discussion of the laws of thermodynamics, which will provide a further framework for the study of chemical systems. We will approach these laws using a semihistorical perspective. Not because we are interested in the history of the development of these laws, however interesting it may be, but because this provides us with an easy and conceptual picture of their scope and enunciation. As we do this, we will move pretty far afield from chemistry. We must keep in mind that our discussion will eventually lead us back to theories concerning the physical properties of chemical substances. And these theories will be framed within the framework of thermodynamics. Atkins says this rather grandly:

Mathematical modelling in physics and engineering. II

Abstract: For pt.I see Phys. Educ., vol.17, p.220 (1982). The authors present an example on mathematical modelling in the classroom, called 'Power from windmills', which has considerable potential for development both as a model and as a series of modelling exercises of increasing difficulty for students with different backgrounds.

A basic surface tension apparatus for educational purposes

Abstract: The author describes a very simple apparatus for measuring surface tension using the maximum bubble pressure method.

The place of astronomy in schools

Abstract: For well over a decade there has been great interest in astronomy throughout all the age groups in our schools. Many people consider this to be due to the space age and its attendant ballyhoo from all branches of the communications media. I suspect however that the interest was there even before space became popular as a source of science spectaculars.