Teaching Java using Greenfoot to KS4: December 2011

Introduction

We now offer OCR AS Computing to our KS4 pupils as an alternative to the GCSE ICT course. Pupils will study this course over two years; it is normally done in one year by 16-17 year olds but given the excellent students we have here, I think they will cope. Just under 50% of the pupils opted to do this course when they had to make their choices at the end of Year 9. There is no coursework in the OCR AS computing course (which ironically means we will be able to do more practical work as we won't have to jump through hoops).

The pupils are all girls in a high-performing grammar school. They have all had some experience writing code in previous years; they have used Scratch to write a shoot-em game, VB.net to produce a web browser, Logicator for flow charts and html to produce web sites. Pupils on this Computing course will have three 50 minute lessons a week in both year 10 and 11; one lesson is intended to be a pure theory lesson and they will also have a double lesson lasting 1 hour 40 minutes in a computer suite. I expect them to do about an hour or so a week of homework. Pupils will primarily be learning Java. The main IDE we will be using is Greenfoot (excellent and free). We will be working from the Michael Kolling Greenfoot textbook and using resources from the Greenfoot website. We may dabble with other languages and IDEs.

The broad plan for the first year is to program program program by teaching pupils how to write computer games. I intend covering as much of the Greenfoot textbook as possible and as much of the Programming unit (OCR Syllabus F452) in year 1, and then the theory parts (F451) in year 2. By the end of the first year, I want the pupils to be able to confidently write their own computer games.

Thursday 8 December 2011

So, how has it gone this term and where to next?

The hols are nearly with us. We shall spend the rest of this term playing with arrays. In January, we need to look at records, then functions and procedures and a bit on recursion. A few weeks spent on opening and closing files, reading data from them and the like and we are done with round one of teaching the basics they need to know for the syllabus.

The question really is how to move forward from mid February. What I really want to do is go through everything again but in more detail and give them more opportunities to write and experiment with code. We could carry on with BBCBASIC. I like the language but it has limitations, not least of which is the cost for pupils to put on their home PCs if they are to develop larger programs. The debugging tools are limited, too.

I could return to Java but I'm worried! We used Greenfoot. We had a lot of fun using the first five chapters and it really got their imagination going. BUT and it's a big but, chapter 6 onwards was difficult for a significant number of my very bright students (remember, this is a grammar school). Pupils started a bit of chapter 6 and I found they could copy but had little to no understanding of what they were actually doing or why, so they found it difficult to start the first few steps to independence. That's why we stopped and moved to BBCBASIC. Java's syntax is also a lot harder to get to grips with and some of concepts that get introduced from chapter 6 onwards are pretty hard for a 15 year old.

The OCR specification is more geared up to learning a procedural language, which is a problem when you are using an OO language like Java! you can still cover much of the basic programming stuff but talking about top-down design and functions and procedures gets a bit tricky! The other problem is my own weakness in Java. I spend a lot of time trying to get my head around some of the abstract goings-on in Java and then trying to work out how to make it clear to youngsters. There isn't enough time in the week and unfortunately, there is zero help and training for teachers like me during work hours. I have a good set of books, a great set of online resources, some forums for advice, but still - it's hard without someone to sit and explain things and help you work through a problem you have in programming.

Then there is a compromise. I guess I am old enough to be part of the Pascal generation and something like Delphi might be best. The Lazarus IDE is open-source and well supported. We can cover the specification that OCR sets easily. There are some great resources around, particularly on YouTube, and we can easily move on to creating forms-based applications from console-based ones. I've also taught Delphi in the past and am a lot more confident with this than Java. And of course, it will be exciting for pupils to learn a new language and they can practice again all the things they did in Java and BBCBASIC, and then extend those skills.

I wonder if I am too hung up over teaching OO, or indeed any form-based application? I think I'm talking myself into Pascal using Lazarus but need to thing about his over the next few weeks.

What to do to do to do? What to do?

Monday 5 December 2011

Week 10 - Arrays

We ran through one and two dimensional arrays in class, comparing them to using a bunch of variables. We talked about setting up an array and how we can visualise a one and two dimensional array. We then dry-ran initialising them, writing to and reading from them.

New challenges were set around arrays. Pupils were given a program that used an array and asked to comment each line. They then were told the data to use and had to do the trace table for it. Then they had to get some small array-based problems working, extending them as they went.

BBCBASIC is a really good introductory language to use. The more we use it, the more I am impressed. It's very forgiving, pretty clear and uncluttered and there is enough help out there to make life easy. If I had to be critical, I don't think the debugging tools are very good. Pupils really need to be able to step through the code and trace the path, watch variables and elements change. But as an introduction, it's superb and will be part of future teaching plans from now on.