Sub Ubi

I thought I’d run a post that is pulled straight from the greenfoot-discuss mailing list. I thought it was a good user story, as it illustrates some of how people “out there” are using Greenfoot, as well as being a fun read. At least, as someone who has taught Java using the Objects First textbook and used Greenfoot in the classroom, I certainly enjoyed the read.

This note comes in from Barry Brown at Sierra College:

I’ve been running a CS11 class this semester using BlueJ. I saw Greenfoot demoed at SIGCSE2 and participated in the Greeps competition.

Once the students completed chapter 4, I thought it would be a perfect opportunity to have a bit of fun and give them lots of practice writing Java. For two weeks, my students tackled the Greeps competition.

A bit of background: my students range in age from 17-ish up to the 40s. I have three high school students among traditional and returning college students. The students’ experience with Java is mixed; some were beginners and others had been exposed to Java before.

I introduced the competition on a Monday. They were shown the Greep class and the inherited methods from Creature. I started them out with a few hints, such as the obvious improvement of having the Greeps turn away from the water or the edge.

On Wednesday (two days later) we had the first round of competition. Of course, I ran the Greep classes on all ten maps. The top five finishers scored 52, 56, 61, 68, and 244. Interestingly, the 244 score was earned by a pair of the high schoolers and falls only 1 point short of the overall winner at SIGCSE.

Next Monday, we ran the Greeps again. This time the top five scores were 150, 174, 195, 215, and 254. The top two scores were earned by the same pair of students who were the top scorers in the first round. (They decided to split up and run their Greeps separately. Later, I would find it was a carefully calculated strategy to win.) Nearly all of the students had figured out how to get the Greeps to stop at the tomato piles and most had some kind of algorithm to steer them around the water.

Finals were on the following Wednesday. As with the SIGCSE competition, we did best-of-three for the finalists. The top five scores were 198, 206, 230, 236, and 281 with the top two scores being earned by the same two high school students.

Feedback from the students were overwhelmingly positive. Memorable quotations:

This was a lot of fun.

Much more fun than BlueJ.

I spent more time on Greeps than my other classes.

All students got a lot of practice invoking methods, reading documentation, writing loops and conditionals, and learning to make use of limited resources. In fact, by the time we got to Chapter 8, the subject matter of inheritance was easy and obvious. They had seen it all before in Greeps!

Kudos go to the Greenfoot team. Playing with Greeps was a fun break from the BlueJ exercises. I’m not sure if I would use Greenfoot exclusively next time, but I’m really leaning toward mixing BlueJ and Greenfoot.

What I like about this post is not just that it is a positive reflection of the use of Greenfoot in the classroom, but that Barry has provided a glimpse of his thoughts on how he would use it in the classroom in the future. The notion of mixing Greenfoot in with exercises from the Objects First textbook is certainly a good one, and might provide some good direction for a set of companion modules that instructors might use throughout the text for enrichment.

Also, what I think is even cooler was the constructivist learning that took place through the use of the Greeps competition. In particular, the students were not phased by the notion of inheritance when they saw it in the text because they had leveraged it throughout the Greeps competition. The purpose of the competition was to score points; however, the students were willing to tackle new learning in their attempt to score more points in the Greeps competition. This kind of self-driven, authentic learning is (in my opinion) the most powerful kind of learning an instructor can encourage in their classrooms. It usually requires giving students ill-defined challenges, and being willing to relinquish some control over how things will progress… but the rewards in terms of learning outcomes can be significant.

So, very cool stuff. That’s it for today, but in my next post, I really want to dive into a new feature in Greenfoot: the ability to export projects for sharing on the web! This is at the heart of the MyGame site, and will factor heavily into what I’m working on over the next few months. I think it is awesome, and before I’m done, I expect you will too.

Footnotes

1 CS1 is shorthand in the USA for a first course in computer science. It often implies a programming-intensive course, but not always. (back)

2 SIGCSE is the ACM Special Interest Group in Computer Science Education. When used in this way, “SIGCSE” implies the annual conference held in the USA each spring. Roughly 1400 computer science educators from all over the world, typically working with high-school and university-level students, attend. (back)

Michael posted a complete gallery of photos from the contest on the Greenfoot site. He did not, however, capture our top winner in a reflective, contemplative pose:

“I can beat that guy…”

Joe Coglianese showed that professors from big-name Universities have to get to work on their Greenfoot chops pretty early in the morning if they’re going to beat a hard-hitting high-school teacher. The competition was great, really–it was so much fun to see people hacking, submitting, tweaking, submitting… trying to get their Greeps to exhibit that critical bit of emergent behavior that would score more tomatoes than anyone else.

Our winner, observing from afar… sneaky.

It was impressive how many people were drawn to the Sun booth by Greenfoot; I like to think that the combination of the activity and Sun’s presence fed off of each-other very nicely. Some people came by to find out what Sun had going on, and some came by to see Greenfoot–and they usually asked questions about both. That was cool, although from time-to-time I found myself answering questions about OpenJDK, the J2ME stack, JavaDB, and OpenSolaris. (Yes, you can run OpenSolaris in a VMWare virtual machine.)

And it was also very cool to talk to people about the ideas they had for teaching with Greenfoot. So many people were coming up with such cool ideas for how they wanted to get students playing with this environment. I’m hoping they find their way back and share some of their stories, as I’d very much like to do some interviews, ask questions, showcase student work, etc. in this space. The more we share with each-other regarding our use of Greenfoot in pedagogic contexts, the more we all benefit.

Why? Because Greenfoot is amazing. See? Look. This next photo proves it:

Greenfoot is amazing

LOOK AT THAT! Look at how amazed I am by Greenfoot! Mercy. I can’t be more amazed than that. Michael is amazed too, which you can tell even from his back–look at how excited his shoulders are! Ian (left) isn’t all that amazed, but that’s because he used to program in Postscript, and is now scarred for life. However, there are people in the background who are about to be as amazed as I am, but they’re slow on the uptake. Dennis (behind me) in particular: not terribly observant, that one. In a moment, he passes out from the excitement of Greenfoot. He gives new meaning to the words “completely floored.” Really, Greenfoot is absolutely amazing, it is.

…

(I did not pose for that picture, and I did not have to ask Poul to take it several times before we got just the right expession of amazement on my face. That was a completely natural, un-planned expression of just how amazing Greenfoot is. Really.)

(And yes, I had fun writing this post.)

There’s a lot of microworlds out there. The original microworld was probably LOGO (Wikipedia), with its iconic turtle. Today, there are countless environments in which students can create characters, agents, worlds, universes… all programmable, all creative, all quite cool. Alice comes to mind (a 3D environment in a novel language intended for beginners), as does NetLogo (a massively parallel LOGO). And if you’re open-minded, things like the LEGO Mindstorms is a physical manifestation of these agent-based microworlds… a real, robot agent that kids of all ages can program and play with.

Why, on the Greenfoot weblog, would I be pointing to… the competitors? Humor aside, each of these environments provide a very different way of approaching the same ideas, and as users and educators, we stand to learn a great deal by looking at a broad spectrum of tools. At one level, all of these programmable microworlds provide opportunities for beginners to program in an interesting and engaging environment. At another, they challenge students to think about an interesting class of problems: software agents interacting with each-other, dynamically and (in some cases) unpredictably. This is critical in the real world: programs that interact with databases, webservers, and the like operate in fundamentally the same (unpredictable, agent-based) space.

In the case of Greenfoot, there’s an added benefit that the language encounter Java. Java is widely used in the world today, and the object is a reasonably natural way to represent an individual agent wandering free in the world. What I particularly like is that the notion of an object (an abstract concept that is often difficult to explain to a novice programmer) gains a visible analogue in Greenfoot: “that (ant, wombat, thing on the screen there) is represented by an object.” Students can inspect those objects (just like in BlueJ) and see how their agent’s state changes as it wanders about in the world. That, I think, is quite cool.

Since I’m actually at the beach, I’m going to stop my musings on “why I like Greenfoot”… as I should be out enjoying the sun! However, I’ll continue these thoughts from time-to-time. If nothing else pulls me away, I have to make sure that the fish stew I’ve planned for this evening continues as planned. We have a nice, long-grain brown rice, 2lbs of fresh shrimp, 3.5lbs of assorted, firm white fish (all fresh off the boat!), lots of fresh tomatoes, and good garlic bread and salad to go with. Yummy.

The Marine Biology Case Study

Given that I’m on the shore, it’s a perfect time to mention the Marine Biology Case Study, which is now available as a Greenfoot microworld. This was an example project used by the US College Board for the AP Computer Science course; now, it’s far more interactive and interesting to play with. If I can’t wrangle a guest blogger here to walk us through the case study, I’ll dive in and do my own exploration. Marine biology and beaches: two great things that go great together.