Flow+Chart+-+Planet+Classification

Meagan Morscher, February 2012

Day 1: show the students a youtube video clip from an episode of the Big Bang Theory - "The Friendship Algorithm". In it, Sheldon creates an algorithm for making friends (he's not very good at it naturally). He expresses it in the form of a flowchart - it is cute. So they'd heard the words algorithm and flowchart.

Day 2: I started the discussion by mentioning that movie clip, and giving a very brief (5 minute) blurb about what a flowchart is and why it can be useful for helping to understand and solve a problem, and to be able to communicate your solution in a clear way.

Then onto the planets activity.

We asked the students to design a flowchart that would represent their definition of a planet. We provided a place for them to start: "Choose a celestial object." This would be a possible first box to put on their flowchart. Their flowchart should be able to take in any object, and based on properties, it would decide whether it was a planet or not. We let them go.

It didn't go extremely well. Problems: (1) they didn't have a good sense of how to start; they'd seen a (complicated) example (Friendship algorithm), but that was it. (2) They sometimes tried to go into too much detail (classifying all the different types of planets, and non-planetary objects, like comets, etc. They got confused, and things didn't work out so well. And their results were very specific to our solar system.

REVISION:

After talking during our free 2nd period, we figured out how to make some big improvements.

In the next class, after introducing the idea of flowcharts and mentioning that we were going to make one to determine whether an object was a planet or not, I walked them through a very simple flowchart example (well, I made them do most of the work) - classify a shape as a square or not a square. The students provided the characteristics that describe a square, told me how to make the flowchart, with me helping when they got stuck.

After the first trial of that, I started making the students come up to draw parts on the board, with help from the class. The square algorithm was a perfect example! It helped the students see how to CREATE a flowchart - where to start (e.g. "choose any shape"), how to represent the cases when you have to make a decision (e.g."does it have four sides?"), and to understand what the goal is - to figure out the answer to the question "is it a or not," and that the flowchart should produce a definite outcome. They seemed to enjoy doing the example together.

We also suggested that they focus ONLY on classifying objects as planets (or not) first, and if they complete this part, they could move on to subclassify the objects. We wanted to make sure that they had a working flowchart at the end.

The flowcharts they created were much better than the first class. Most finished well before the class period was over. During the period, Andy and I walked around to help them along and to check the logic in their flowcharts (which we warned them, we would do) - we saw lots of good results, and some logic errors that we tried to help them correct. They worked in pairs or small groups, creating just one flowchart per group.

Things I noticed: - groups debating how to do it - challenging/correcting logic of partners - groups spent time to make it look pretty -colorful, artistic (engaged and interested)