Happy Earth Day

For Earth Day today, we looked at binary trees with my IB Computer Science class.

We’re studying abstract data structures, so last week we used BYOB to create stacks and queues with new blocks for all the associated methods you would normally expect with each structure.

The BYOB tutorials cover trees, so I decided to start with with a presentation using Google slides, and a simple scratch implementation, using a set of lists to store the data structure. It would be possible to use a single list to store this data, but that would be less straight-forwards for someone to change.

Scratch Project

Then we went on to do tree traversals…


Our Pitch Video


In case you’re wondering, yes the pitch video for our Indiegogo campaign was done entirely in Scratch! I’ve uploaded the source code to the Scratch website.

Some technical notes:

The background music was provided by Stellardrone,  a very generous musician who releases all his work under a form of Creative Commons style attribution license.

The cog was first drawn in Scratch and then converted to a sprite. However, you will notice that I should have kept the cog and its shadow separate in order to achieve a more convincing 3D effect when animating them.

The presentation timings are co-ordinated by using five different broadcasts to mark the transitions between the different phases.

The video was recorded using Camstudio – free screen capture software, and then tidied-up and converted to a smaller wmv file using Windows Live Movie Maker.