Monday, November 23, 2009

scratchy etoys challenge: some results

I asked students to complete some challenges in both Scratch and Etoys and then provide screenshots and compare the programs. Nearly all students reported that they found Scratch easier to work with than Etoys. No big surprise in that. As Bert Freudenberg has pointed out:
The power of Scratch lies in its limited scope - several years of development and refinement went into it to find the smallest set of features that make it easily teachable while still broadly applicable
(follow the link for Bert's fuller comparison between the two programs)
Here are the challenges again (initially designed for Scratch) with a few brief comments and links to the students blogs for their screenshots and thoughts.

Challenge 1) Use the Letter shapes to write your first name on the page. Then introduce some special effects such as making the letters wobble and change their appearance.

One student did this in etoys as an extension. Since it was an extension he did not have to blog about it. He did a great job it etoys, with the letters of his name chasing themselves across the screen, but it lacked the whirl and fisheye effects that are easy to do in Scratch and are ideal for this challenge.

Challenge 2) Point, click and move
Make an object both point and glide towards the mouse position when you click on the stage
Hint: Motion > point towards
Hint: Sensing > mouse down?

I couldn't fully figure this out myself in etoys and so asked for help on the Squeakland list. I received a lot of help there and so was able to show the students how to do it in etoys. Their writeup is here

Challenge 3) Make Dan or Anjuli or Cassy or ballerina dance to a beat, using all of their dance shapes

Two groups did this. One of them made a series of drawings for the dancer. The other group just dragged the prebuilt images from Scratch into Etoys (both programs running in Windows) and that worked fine. I hadn't realised it was that easy to import images into etoys. The student work is here and here

Challenge 4a) Make two animals have a forwards and backwards conversation
Hint: Use broadcast
4b) Make it an interesting conversation with each animal speaking at least 3 times and making gestures too

I figured out how to do this in etoys but it wasn't very elegant. So, once again I asked on the list and received help from Yoshiki Ohshima who showed me a more elegant method using the Holder.

The student analysis of this task is here

Challenge 5) Make 2 different balls move around on the stage
a) the first ball moves in straight lines but bounces randomly whenever it hits the edge
b) the second moves randomly, changing direction all the time

Because this involved a random bounce off the walls of the Playfield in etoys I thought it was fairly easy. For a true bounce it would have been more difficult in etoys since it lacks a true bounce tile (which Scratch has) and so the students would have had to work out the formula.

oops - Bert Freudenberg has pointed out that the etoys true bounce tile is there and similar to the Scratch tile. I just found it in the motion pane. Thanks Bert. (update 29th November)

Student work is

Challenge 6a) One sprite chases another sprite around the stage. The first sprite moves in straight line but bounces off the edge randomly. The chasing sprite chases the first sprite but is moving slower.
b) Extension – if the chasing sprite catches the other sprite then it says something sensible and makes a suitable sound

The students completed a comprehensive write up of this challenge here

Challenge 7a) Play all the different drum sounds automatically
Hint: create a variable for the drum number
b) Extension – keep recycling through all the drum sounds automatically

Etoys sounds not working so we didn't attempt this. I'm not sure why the sounds were not working for SoaS, I didn't get around to trouble shooting that.

Challenge 8) Make a sprite gradually grow in size and then shrink
Hint: make a size variable

My hint is not necessary here because it can be done without a variable in both programs. Eventually I figured that out and advised the students which simplified the task somewhat. Initially they did it in etoys using diffent sized pictures in a Holder but I told them I wanted a more flexible answer. Their work is here.

Challenge 9a) Count down on a timer. A rocket takes off when you reach zero
Hint: Use the number icons in the letters folder
9b) Your rocket has pulsating exhaust and disappears at the top of the screen

Not attempted partly because it is already an existing Project in the etoys gallery

Challenge 10) Add, multiply or subtract two variable numbers
Hint: Just to do addition only you will need 4 variables: firstNum, secondNum, answer (computer calculated) and myAnswer (human calculated)

This is written up in here (Scratch solution) and here (Etoys solution)

Challenge 11) Variable coloured squares
a) Write a script that can draw a square of any size
Hint: Make a variable for the side length
b) Use the variable square script to draw a series of square with variable sides, with a single click
c) Now add variable pen colour and pen shade to the variable square script and use it to draw a variety of different coloured squares, with a single click


One thing I noticed about part (c) is that it is difficult to programmatically increment colours in Etoys because they are not represented by single numbers

Footnote: I'll update the links to student work as it is completed in the next few days.

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