Maria Knobelsdorf, University of Dortmund, Germany - Didaktik der ...

ehind the small suggestion to employ experiments in CS education
is meant as a step towards this direction. The educational goal
is to emancipate and educate all, so that they can use and modify
or even create digital artifacts according to their own creativity
and needs. And on a general level, to support well-being and
development of society as such, by being a responsible and participating
member of (the digital) society.
4.1 Goals
In summary, the duality of function and structure is an analytical
perspective that should frame the perception of topics to learn for
teachers and learners. It highlights some aspects, and is therefore
connected to certain goals:
Link computer science to ICT-experiences from everyday
life.
Foster interest and motivation.
Foster integration in long term memory by linking new content
(mainly from structure) to already known topics from
everyday life (mainly from function).
Develop / teach competencies to analyze different kinds of
digital artifacts (and thus foster self-efficacy and maybe
change attribution).
Demonstrate the relevance of CS for future development; in
personal life as well as with regard to the wellbeing of society.
This has three facets:
Getting help for usage problems (reattribution, get problem
solving ideas based on structure knowledge) and
hence acknowledge the (immediate) value of the learning
content,
Understanding the internal mechanics of digital artifacts,
as a) a prerequisite or aspect of learning programming
as well as b) an aspect of understanding the
dual nature of digital artifacts.
Understanding the need (and role) of design (structure);
and therefore be able to alter or widen conceptions of
computing disciplines and the role of computing professionals.
Teaching and learning methods are needed, that provide bridges
between structure and function. Experiments - understood similarly
to science education - are promising candidates to build such
bridges in the CS classroom. In science, experiments are rigorous
methods developed to test (and sometimes develop) hypotheses
about phenomena in nature. They are different from the everyday
meaning in which experimenting is often associated with tinkering
or trial and error. In the next section, examples of experiments as
bridges between structure and function are presented and briefly
discussed.
5. DUALITY EXPERIMENTS
In this section some examples are given, which show a variety of
experiments as teaching method in CS education. In doing so, the
rationale behind and the desired effects are discussed.
Note, however, that the examples are more or less based on literature.
All of them were enacted, at least in basic form - but not yet
empirically evaluated within the above outlined approach; therefore
the intended effects are described on account of the described
theory, and are not empirical results.
5.1 The cell phone network
Using cell phones / smart-phones is an everyday activity of school
children. E.g. in Germany 96% of all teenagers (age 12-19) own a
mobile phone [26].
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The teaching unit focusses on location based data produced by
mobile phones. In a first step, students are uncovering structure
and function of the cellular network.
A small experiment can be used as a motivating introduction[30]:
Two cell phones and a metal box are needed. In the first experiment
one phone is placed inside the box, which is closed. What
happens if one tries to make a phone call to that phone? It
wouldn’t ring because it is not available – no connection from the
other phone is possible. In the second version of this experiment,
the second phone is – after dialing the number of the first – also
put inside the box. What happens now?
This starting point raises the question how the cell phone network
works – what is its structure? A part of it is the need to localize
the mobile stations (the cell phones). And therefore, in the example
above, both phones in the metal box cannot connect to the
base station, and the called phone wouldn’t ring.
In a second step – which also may be called an experiment, but
more correctly is a role play – learners encounter the basic structure
of a cellular network (mobile stations, base stations, and the
central switching station with home location register) by enacting
(or experimenting with) use cases like connecting to another
phone. By enacting several scenarios learners will discover that
besides the content data (what they are talking over the phone)
also traffic data is transmitted and collected. Of these traffic data
the location data is in focus of the following step.
In [4] an example of location data collected by the phone service
provider is shown, including the raw data as a spreadsheet, an
interactive visualization and an interpretation of the data.
The learners will visualize the location data themselves, by using
a predefined framework. This framework allows inserting a
graphical representation (e.g. a dot) at the geographical coordinates
in one of the typical online maps (like OpenStreetMap).
Experiments with the data are made by changing the visualization,
e.g. adding a counter for each position and/or filtering for time
slots. For example, showing the position of the cell phone only
during night time indicates the residence of the cell phone owner.
These activities (producing different visualizations of the same
data) demonstrate the information that can be revealed, and what
possible (future) use of that information may be possible. This
includes a demonstration and discussion of location based services
like Google traffic, which predicts traffic conditions, based on
accumulated location data of cell phone users [27].
Students can learn – among other aspects – how computing is
changing and devolving, and eventually reflect on their conception
of computing disciplines.
In summary, the above outlined experiment (or, if you will experiments
(box, role play, and interactive visualization)) is aiming at
visualizing structure, namely effects of the receiving signal
strength, important parts of the cell phone network, and location
data. The main role of the experiment is to build the above mentioned
bridge from use experiences to perceiving the structure of
the cell phone network. It should do so by making the learners
curious and start to ask, what will happen and how does it work.
In other words, it should raise awareness for aspects of the otherwise
hidden structure of the cell phone network. The playful
approach should be motivating by making learners’ curious and
asking themselves, what will happen.
The immediate benefit for users is small, however. It may only a
better understanding of connection errors. In addition, the experiments
might raise the awareness of differences with regard to the
precision of one’s own location data, and that it can be influenced