If You Build It ...

Thomas Kelley
Northeastern University,
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This classroom activity is hands-on building project designed for teams of two or three members. The teams will build a specified structure from Lego bricks (or some similar building blocks), record their construction procedure, exchange their instructions with another team, and attempt to reconstitute the original structure. The goal of this activity is for students to associate aspects of their instructions to aspects and conventions of algorithms in general and computer programs specifically. It should also introduce students to the usefulness conventions and functions when writing programs.

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Learning Goals

From this activity, students should:
1) Write systematic steps to accomplish a task
2) Recognize similarities among their list of instructions, an algorithm, and a computer program
3) Understand the advantages of functions in computer programs

Context for Use

This activity is designed for the first full class of a programming course for high school seniors or college freshman. At least 40 minutes should be set aside. Programming or specified technical knowledge is not necessarily needed to accomplish this activity.

Description and Teaching Materials

1) Divide class into teams of two to three people
2) Divide blocks into sets such that each group receives two bags of building blocks. Each bag should contain identical sets of blocks (same size, number, and color).
3) Come up with a list of simple structures. The groups should be able to design and construct this structures in 15 minutes.

Class time:
1) Give each group a pair of identical sets of blocks and a piece of paper specifying what structure they are to build.
2) Allow 15 minutes for the groups to construct and write instructions on how they built their structure. Each group should use only one set of blocks.
3) Have groups exchange their instructions and second set of blocks with one another.
4) Allow another 15 minutes for the groups to use the instructions to reproduce the original structures.
5) Compare structures
6) Lead a discussion about the activity. The attached assignment sheet has a list of possible questions to discuss.
Group Handout for Classrooom Activity (Acrobat (PDF) 42kB Sep29 16)

Teaching Notes and Tips

The effectiveness of this whole activity rest with you relate this activity to writing a real algorithm or computer program. Outside the 30 minutes of construction, you should be prepared to commit another 15 minutes to the discussion.


Student groups should assess how well they reproduced the structure from the instructions they received and how well their "partner" group reproduced the structure with their instructions.

References and Resources