Notebook Computers and Learning in Physics - How Can They Help?
Jon M Pearce and Michelle Livett,
This paper describes a project in which five first year undergraduate physics students were given Macintosh PowerBook computers for their own use for one semester. They were set regular spreadsheet modelling tasks aimed at helping them develop better conceptual understanding of physics. This paper focuses on the nature of the tasks set, the students' reactions to them, and the authors' impressions of the way in which such use of computers should be developed.
The five students had a variety of backgrounds in the use of computers, all having had some experience with a Macintosh. They were lent the PowerBook computers on the understanding that they would meet every week with two staff members to discuss their experiences. The tasks set for them were relevant to their course studies at the time and aimed to provide an alternative medium in which the students could `play around' with the physics. This usually meant constructing a spreadsheet model and exploring its behaviour.
The software used was `ClarisWorks', an integrated package comprising word processor, spreadsheet, database, communications and drawing components. The students were encouraged to communicate with staff at other times using electronic mail (`QuickMail').
Initially a simple task was presented requiring students to explore Ohm's law and series and parallel combinations of resistors. The description of the task took the form of a ClarisWorks word processor document which described both the physics and what they were expected to do. That document also contained a spreadsheet representing two resistors connected in series. A diagram of the circuit overlaid the spreadsheet, giving the appearance of a labelled circuit diagram. This structure enabled students to change a label value (say, voltage) and observe the resulting changes in other values (current).
The aim was to introduce the students to a means of compiling a `physics workbook' containing active diagrams representing the models they constructed. Lining up the diagram accurately on the spreadsheet was sometimes time consuming, and often the diagram part was omitted. It was hoped that by exploring cause and effect relationships between quantities in their models students would develop their intuitive understanding of the underlying physical relationships.
Students were required to complete the set exercises and submit them by email. The extent of use of pre-constructed spreadsheets diminished as they became more competent with spreadsheet design.
Observing students grappling to become familiar with spreadsheets at the same time as exploring new physics made us aware of the tension between focusing on computing and focusing on physics. To help alleviate this conflict, we introduced the idea of causal arrows. These allow one to delineate cause and effect relationships on a diagram in a way that supports the later construction of a spreadsheet.
One situation students investigated was the force between two long, straight current carrying wires. A beginning point was to consider the field produced by one wire and the parameters that determined its magnitude:
The diagram shows that the field B, produced by a current I coming out of the page, is determined by the current (I), the distance (r) and a constant (u). The arrow was important in emphasising that I causes B. This helped in sorting out the confusion students have with two current carrying wires as to which field acts on which wire to produce a force. That is, they have often not sorted out the distinction between the parameters in the expressions:
B = f(u[[omicron]]I,2[[pi]]R) and F = IlB
Having drawn the diagram, a spreadsheet could be constructed following the same layout. For example, the process of drawing the causal diagram emphasised that the cell which calculates B must contain cell references to r and u. The spreadsheet might be laid out as shown below:
A student response to the task of exploring the forces between two currents, could be:
and similarly for the magnetic field produced by I2 and the force it exerts on I1. This forms the basis of their spreadsheet.
Each student was interviewed midway through the semester and again at the end. The following comments generalise their views.
There was an initial period during which the students' focus was the computer rather than the physics. They very quickly built up confidence and competence with the Macintosh and the portion of time preoccupied with the computer diminished. However, skill development with the spreadsheet was slow, even though they had had some prior spreadsheet experience in their physics studies. An initiation period for development of these skills would have been desirable.
The students reacted positively to the visual communication aspects of the computer. The quick and easy way in which they could explore and make changes to models was appreciated. In particular they perceived the value of immediate response to parameter value changes in developing an understanding of the links between quantities within the model. The reasoning process required for setting up the spreadsheet was seen to be valuable in sorting out conceptual relationships.
Students also preferred working with a screen rather than pen and paper, which they regarded as mundane and monotonous. As one said, "we're a screen orientated generation!". They saw the tasks presented to them as valuable in their own right; a supplement to, but not a replacement for, more traditional problems.
They were concerned about the weight of the PowerBooks (2.3 kg) and about the security of such machines if they became common place amongst students. Cost would be a prohibitive factor for many of them in buying their own, but each said they would buy one for this use had they the money.
If computers are to be well integrated into a physics course, and accessible to students as an aid to their conceptual learning, then students need to have access to them at all times (not just in computing labs) and be encouraged to develop skills that let them explore ideas and models in their own time. If all students have such access the we must re-examine our courses in this light. More emphasis should be given to numerical problem solving, for example, rather than analytical. More time could be spent by students exploring their own models rather than reading the descriptions of them in texts.
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