Control and monitoring: 'What happens when'
Key idea from QCA 6C: computers can monitor physical factors.
In the computer suite, 2 mixed ability groups took turns to work with Robolab while the remainder of the class worked with floor turtles and Roamer World. Work took place over ½ a term, for 40-50 minutes once a week.
Robolab groups started from scratch, learning how the software worked, and how to download programs to the RCX brick. They learned how to change the Pilot Level templates, and how to write their own programs. Firstly, they learned to control lights and motors (outputs), then touch and light sensors (inputs) were introduced.
Discussion revealed that many children had not previously considered the difference between timed events, and events that occur as a result of a physical change, for instance in temperature, light or sound level.
Pupils began with Robolab introductory worksheets, then progressed to two worksheets which I had previously devised. These sheets introduce the children to the way Robolab can be programmed. Once they had understood Pilot Level basics, I introduced the Inventor level. Using a simple windmill,I asked the groups to devise a program to run first one motor, then two motors and a lamp. I also asked them to make up a story to be read as their program ran.
The final part of the work was to use the sensors to control events. Pupils built a model house with a motor-operated alarm, activated by a light sensor. The sensor detects darkness when someone passes. The rotating alarm strikes a metal lid, making a loud noise.
Assessment point: Group members will say whose idea it was to introduce something: they are usually very honest. This means it is not necessary to monitor progress continuously.
Pupils H and J were members of one group of four. H is a pupil who, in other activities working with the computer, has been quite hesitant but has always "got there in the end": general approach to school work shows a lack of confidence but average attainment.
H said little throughout, while helping with the building of the model. H quite readily took turns with writing the program, wiring etc. It is difficult to say to what extent H needed the support of the group. I suspect that making decisions (e.g. which motor to run, and for how long) would have been more of a hurdle, than actually understanding the need.
H watched as the story was typed by J. H checked what came next in the program, but made no obvious contribution, and did not suggest changing the program in any way.
J is a pupil who has worked confidently with the computer in other activities we have attempted. In general schoolwork, J is an average pupil.
J talked about what the group were doing as the programs were written, asking others' opinions and giving a point of view. J even argued against some decisions and putting forward valid reasons why times should be longer, and why things should happen in a different order.
Together, J and H wrote their story to fit the group's program. Neither made any attempt to change the program to fit the story, once it was finished.
H's quiet nature made it difficult to assess the level of understanding. Had there not been a whole-class follow-up session, where everyone was asked to try and write a sensor-activated program, I would only have awarded Level 3. However, H produced a quite acceptable idea showing good understanding. A low Level 4 seemed more suitable.
J successfully refined the program to fit the story, adding a repeat loop (readily recognised as the way to prevent further burglaries). J seemed a confident Level 4.
To improve: pupils H and J needed to suggest/ make changes in the program to ensure the story they wrote fitted in better.
They recognised that a repeat was necessary to keep their program running after the first burglary, although they did not have time to write that in during the lesson. They could develop the program by introducing modifiers to change the brightness of the light, or the speed of the motor at various times
R works confidently with ICT, and is an above average pupil. R talked within the group about what the program would do. R asked others' opinions, giving a point of view, even arguing against some group decisions. R put forward valid reasons why times should be longer, why events were not "lifelike", why things should happen in a different order, etc.
R would have really liked to have the chance to work alone, once the group had written and tested a program and a playlet had been written. In fact, R took over refining the program. R changed the speed of the alarm motor, the timing of the lights and the order of events, to fit better with the story. At this point, others in the group wanted to improve the model, adding decoration and other extras for the play!
R also asked to add music notes as a police siren, but time did not allow. The desire to add to the program, together with R's input during its creation, shows that this pupil has achieved Level 4, and is moving towards Level 5. With more time, R might continue the project and confirm Level 5 attainment.
Notes on supporting learning
There is a fine line in this type of work between telling the children what to do ("Your program will need to repeat itself X times"), and teaching them the skills needed to develop their ideas ("What happens if the burglar comes back? How can we make sure that the burglar doesn't come back and take the valuables?"). The temptation is to try to cover more ground than a group may be ready to understand.
With experience, the teacher knows when to ask the question: "Have you thought of trying..?" Pupils confident to progress will respond positively. A negative response, or replies like"We haven't tried yet...That sounds hard!"mean that more practice is needed.
With this work it is important that groups have as much time as they need to experiment with the template programs. They need make changes, and see and understand the effects of these changes, before they move on to designing their own programs or adding more sophisticated parts.
Programs should be built up stage-by-stage with additions and amendments as pupils realise the need. This is especially important when groups may have more than a week between turns. Unless foundations are secure, each new session involves a lot of revision and/ or direct teacher intervention.
Program writing is not a trick to be learned, but a logical sequence of ideas. We all remember the days when children were asked to write instructions for a simple task, then forgot the most fundamental. Control gives an opportunity to solve open-ended problems. The child's understanding of each stage is paramount. Pupils with the understanding and confidence will naturally develop more complex programs.