Lesson 9:
Challenge Missions I

1. Decompose a problem into component parts

2. Use multiple testing and debugging strategies to improve a program

1. Decompose a problem into component parts

In reflection question 1, ensure that students have broken down the missions in a logical way, based on patterns or clear groupings of sub-goals.

2. Use multiple testing and debugging strategies to improve a program

In reflection questions 2 and 3, check that students have referenced running code to see what happens as a part of the software development or debugging process, and that they have cited at least one effective debugging strategy.

Slideshow: Challenge Missions I

1. Give an example of how you were able to take one big, complicated mission and break it up into smaller challenges.

Student answers may vary, but they should demonstrate a logical decomposition of any of the sample missions. For example, the ‘Zig Zag is Back’ mission can be separated into two different zig zag patterns, ‘X Marks the Spot’ can be separated into four identical challenges in which the robot turns and touched a block then retreats to the center, ‘The Pentagon’ and ‘The Other Way’ can be separated into the polygon’s sides, and ‘Big Challenge’ can be broken into a square, semicircle, and triangle.

2. Describe a time your program did not work as expected (a bug!) and how you were able to find the problem and debug it.

Students should describe the debugging process, in at least broad strokes. These should include how they noticed the bug in the first place, an effective strategy for finding and correcting it (e.g. running the code to see where exactly the robot deviated from the expected path, looking at similar missions that were completed correctly, tracing code by explaining its behavior step by step, or collaborating with a friend).

3. Why might a coder want to run the program, even if it’s not completely finished yet?

Student answers will vary, but they should show an understanding that there is value in testing incomplete code. For example, in the last mission, students may want to check that the robot can complete the square before moving onto the semicircle. Students also may run code to test whether their understanding of a particular block or algorithmic structure is correct before relying on it in subsequent parts of the program.