Netbooks on the road

May 23, 2008 on 6:08 pm | In KS4, Public Understanding of Science, algebra, constructivist approaches, engineering, graphing, mathematics, mobile computing, models, physics, practical activities, review - equipment, secondary education, user stories, wider context | No Comments

My part of this “netbooks” trial involved much hair loss. Since the base for my work with disconnected teenagers is a cybercafé, there is no obvious rôle for a small, pocketable computer in the normal context of what I do. To make good use of the opportunity, I had to let these machines go out of my control, into an environment where small high value objects are regarded as currency. The sponsors said they were willing to take the risk of loss, provided that I took what I considered reasonable care to minimise it … what, exactly, constitutes reasonable care when handing expensive stuff over to teenagers who may not come back, have class A drug habits, and are due in court on Wednesday for handling stolen goods?

The other question was what exactly to do with these machines, to justify taking the risk. These two issues were linked; my clients had to feel that something worthwhile was going on, if they were to respect the tools involved.

One subject which interests all of them, regardless of gender, is cars. A month before the netbooks arrived, I started discussing with them the relationships between weight, power, speed and acceleration in a car. They have rather more practical understanding of these matters than can be easily explained by legal experience at their age so I concentrated on trying to relate this to theoretical engineering models, first visual and then symbolic.

With the netbooks on hand, I brought the talk around to how we might investigate the actual (rather than maximum or advertised) speed and acceleration values for real cars in daily use. They were very interested in this idea, and were keen to try their hand at using spreadsheets for the purpose. Then they realised that they would have to write down a lot of information and bring it back to the centre, then key it in, before they could do anything with it; at that point, disappointment and loss of interest threatened. Like a good conjuror, I then produced the netbooks.

Gathering data

The scheme they devised involved teams of six, each team stationed downstream from a Pedestrian Light Controlled crossing (this allowed two teams per crossing, getting double data for each red light, at three different crossings). The team leader (let’s call her or him “A”) would stand by the lights themselves, and would have the computer with an open spreadsheet. “B” through to “F” would be at measured distances downstream from the lights.

When the lights turned red (probably because “A” had pressed the button, but I didn’t enquire too closely), “A” would take up a position beside the frontmost car and enter details (make, model including engine size if possible, number of occupants) into the spreadsheet. When the lights went amber, “A” would raise his or her arm and the others would prepare to start stopwatches (mostly on mobile phones, though a few used the function on their wristwatches). When the lights turned green “A” would drop the raised arm and start walking up the line; the rest of the team would start the stopwatches running.

As the lead car passed each team member, the stopwatch at that position would be stopped. As “A” reached each, the time on their stop watch would be entered into the spreadsheet. In this way, a database of timings at fixed distances for different vehicles was built up. The results were also visible in a predefined scatter plot at the right of the same screen, with an interpolated trend line, so the model could be seen developing as they worked. When complete, the sets of data were merged into a single sheet on the desk top and then filtered to compare different data for similar subsets.

As for the risk, I handed over the complete trial set to the two alpha primes in the group (one male, one female) and left them to arrange distribution; and all came back.

Taking it further

This probably seems an underutilisation of the equipment. The same data collection could, after all, have been done with a pocket PC or similar (in fact, the idea was partly suggested by Chandra’s Big Freeze which used Psion clamshells. But the experience of taking “proper computers” out, and being trusted to do so, was worth its weight in gold and stimulated desire to learn. There were, in any case, two follow ups which would not have been possible with handhelds.

First, there was use of a pure mathematics package to compare the experimental data with a theoretical model. Chandra and AbsentCat had described their use of SysQuake LE for projectile modelling. SysQuake is available for both Windows (in the cybercafé) and Linux (on the netbooks) so I installed both. Having set up a basic acceleration equation (d=½at²) on the PC, we set the value of a by trial and error to give a line which matched the spreadsheet data. The young people found this very empowering, and probably learnt more algebraic confidence in half an hour of SysQuake than in all of their time with me to date. They also learned, to their surprise, that most acceleration is over within a very short time (with speed surprisingly low and surprisingly constant) on urban roads.

Second, AbsentCat scrounged us the loan of a set of plug in USB interfaces allowing various types of switch to start or stop timers on the netbooks. The students had a lot of fun with trying out various switching devices. We were loaned some pressure mats which could be placed on the road, though too often the passing vehicles avoided them. We experimented with home made trembler switches, but they were too sensitive, and hard to position usefully. Lengths of rubber tube, filled with water, were laid across the road with light pressure sensitive microswitches plugged into the ends – these were the most successful, and supplied 95% of our usable data.

Broader benefits

The tremblers were a complete failure in data collection terms but worth their weight in gold for the interest which they provoked. A drop of mercury is placed in the bottom of a glass tube; one electrode is immersed in it, and another arranged as a circular collar around the inside of the tube, fractionally above the meniscus; any motion which shakes the tube causes the mercury to make contact between the two electrodes, completing a circuit. Most of my clients have, at some time, been involved in vehicle theft, and immediately realised the relevance of tremblers to car alarms. We got a lot of chemistry, physics and engineering time out of the resulting investigations – even starting a new set of data collection exercises to investigate the link between tube size, collar spacing, and the trade off between sensitivity and discrimination.

This second (more accurate) phase gave us enough data to further investigate the mathematical model, and to extend it into areas such as mechanical work or power/weight ratios. It also allowed us to compare vehicles by type (small car, four wheel drive, bus, lorry, motorcycle, etc). Most valuably, in some ways, it led on naturally to discussing the range of road behaviours exhibited by different users of the same vehicle.

[Contributed by BobTheBumbler]

Portable constructivism

May 4, 2008 on 7:22 am | In Handling data, constructivist approaches, mobile computing, practical activities, user stories, wider context | No Comments

One of my enthusiasms about ICT in education is the potential of connected systems for building genuinely constructivist activities within which learners can invent their own ad hoc subcommunities in mutual support of organised work. Which sounds very fine and impressive, and is in many ways real, but sometimes runs aground on the fact that those learners often have to leave their learning context to access the facilities for doing the constructivist thing. (I’m talking science here, but change the specific examples and everything applies just as much to arts and humanities.)

Real science.

The advantage of portable computing devices is that they encourage “real science” activities out in the world – look at Sayid’s “Pushing up daisies” quadrat activity, for example. To have a spreadsheet available at the same time as fishing around in a ditch for tadpoles, or recording estimated speeds and accelerations of aircraft lifting from a runway, or exploring a lemonade bottling plant, brings the analysis of data vividly to life as part and parcel of the phenomena being observed. When it comes to sharing the excitement with others, though, these devices have their shortcomings.

Generally speaking, a pupil with hand held computer has to store field data in a spreadsheet or database, write notes in a word processor; return to school or home; upload both to a PC or Mac; and only then start to merge them or share them with peers.

With the trial set of Asus netbooks, I was able to take groups of students out and make the computing a seamless part of the fieldwork. There are several levels to this.

Most basic level: sneakernet.

This applies in most field contexts. Here, the pupil enters his or her own data and makes his or her own notes, as in the usual handheld setup. However, a single USB flash drive is circulated continually around the group, each pupil backing up their work to it as it reaches them and then copying a complete set of files back to their own machine. It’s necessary to name the files logically (Jesh_Kaur.doc, Jesh_Kaur.xls; John_Smith.doc, John_Smith.xls; and so on) and to avoid overwriting and keep individual work distinct, but once that habit is established it means that every member of the group has both multiple recent backups her or his own work (on both the USB drive and the computers of other members of the group) and also reference access to near current copies of everyone else’s.

The next level: WAN to go.

This was amazingly easy to set up and use, though not suitable for all settings. All that is required is a wireless router, a power supply, and a relatively small study area. When in a museum, that lemonade bottling plant, or many other visit sites, a temporary wifi zone can (with site permission) be set up in an area such as the café or visitor centre. No internet access is available, but work sharing becomes immediate. If a wifi hard disk is attached to the router, so much the better – all shared work is then available to anyone within the coverage area, regardless of whether its author is within reach. If an adaptor is carried for running the router and disk from a vehicle’s cigarette lighter, good use can also be made of time on the minibus home afterwards.

Continuity at school and at home.

If each pupil is made an author on a shared blog, with restricted readership (to avoid predation risks, but also to provide the group with privacy from nonparticipant peers) and the teacher as administrator, subsequent write ups and analysis can be pooled. By copying and pasting material from the word processor or spreadsheet such blog entries are quickly and easily generated, then can be edited and developed in place. The blog takes care of permissions – each member of a group can red everyone’s material but only change his/her own. A small portable computer continually in the same pupil’s hands, allowing work to be done when that pupil feels like it (at home or at school), able to access the blog whenever and wherever wifi access is accessible, a great incentive to participate.

Team science

All in all, my trial period with these “netbooks” has been the best opportunity yet to develop in pupils a genuine constructivist experience of working in a real community of team science. The pupils working on this pilot responded magnificently, simultaneously nourishing and feeding from each other, exchanging ideas and critiques, competing to be the best contributors to shared success.

All I have to do now is get funding to buy a full class set for long term use!

[contributed by KateQ]