Lesson 8: Project - Make a Library Part 1


In this lesson students begin a multi-day project designing a library of functions. Students will brainstorm common problems they've encountered while programming this year and begin to design functions that address those common problems.


This project caps off everything students have learned about programming as they head into the Create PT. Students are literally "building blocks" that classmates will literally have access to in order to create projects of their own. This kind of thinking requires not only a mastery of programming concepts and skills, but the ability to think more abstractly about how programs are built. Students need to identify common situations or problems that they and other programmers may encounter, and help build commands to address that problem.

This project also caps off a unit that is all about abstraction. On one level students are thinking about procedural abstraction, and simply learning how to design functions. On another level, however, they're learning to think abstractly. They're not merely designing a function, but they're thinking about the entire process of how programs are developed and common problems or situations that arise. This mental approach to thinking about why to build a function is just as important as knowing the steps to design one.


Lesson Modifications

Warm Up (5 mins)

Activity (40 mins)

Wrap Up (0 mins)

View on Code Studio


Students will be able to:

  • Select a theme for a library of functions
  • Design the API for a library of functions, including the function names, purpose, and parameters, and types of values each function will return


  • Review the Project Guide to make sure you understand what students will be expected to do in the project
  • Review the Examples Submission for the Project found in the last lesson of this project


Heads Up! Please make a copy of any documents you plan to share with students.

For the Teachers

For the Students

Teaching Guide

Lesson Modifications

Attention, teachers! If you are teaching virtually or in a socially-distanced classroom, please read the full lesson plan below, then click here to access the modifications.

Warm Up (5 mins)

Prompt: Think back over all the different apps you've built this year. What blocks do you wish already came with App Lab to help you build those apps?

Discussion Goal

Goal: This prompt foreshadows the project students will complete in which they'll be building a library of functions. Sharing this library will allow them to actually add new blocks to App Lab for themselves or their classmates.

Discuss: Have students brainstorm either individually or with a partner. Then have a few volunteers share their ideas with the class.


Today we're going to begin our final project before the Create PT. You'll be building a library of functions that you and others will be able to import and use. You'll get to customize App Lab.

Activity (40 mins)

Group: Students may complete this project individually or in pairs.

Distribute: Give students each a copy of the Project Guide - Make a Library - Project Guide

Project Description - 5 mins: As a class review the project description, what they'll submit, and the steps. Make sure students are also aware that they have access to the rubric.

Teaching Tip

Differentiation: The size of library is a good way to differentiate in this project. Students who are more comfortable programmers should be encouraged to develop larger libraries of functions.

Difficulty of Suggested Functions: The functions suggested in the project guide are loosely in difficulty order. Functions that appear near the bottom of that list are actually quite difficult and will require students to build substantially upon things they've learned in the course.

Step 1 - Brainstorm - 5 Mins: Give students 5 minutes to brainstorm a theme for their library. Many specific ideas are given to students for the types of functions they could write, but ideally students will develop functions that are focused on a specific context they find interesting.

Step 2 - Design - 10 mins: Before students start writing the code for their project they should stend 10 minutes defining the way the different functions in their library should work. This means they'll need to write out the comments that describe the function, the different parameters, and what will be returned.

Step 3 - Build - 20 mins: Give students the remainder of time in class to work on building out their library.

  • Students should start by working on one of their functions that includes all four features. Students will need to develop a function like this as part of the Create PT and also will be answering questions about their function in the free response questions at the end of the project.
  • Circulate the room offering support to students. If they have successfully completed step 2 of their project guides then they should be able to write a lot of code very quickly to set up their functions and comments.

Wrap Up (0 mins)


Great work today. Next time we meet you'll have more time to work on your libraries and then you'll need to share them with another group for feedback.

Standards Alignment

View full course alignment

CSTA K-12 Computer Science Standards (2017)

AP - Algorithms & Programming
  • 2-AP-14 - Create procedures with parameters to organize code and make it easier to reuse.
  • 3A-AP-18 - Create artifacts by using procedures within a program, combinations of data and procedures, or independent but interrelated programs.
  • 3B-AP-14 - Construct solutions to problems using student-created components, such as procedures, modules and/or objects.
  • 3B-AP-16 - Demonstrate code reuse by creating programming solutions using libraries and APIs.


CRD-2 - Developers create and innovate using an iterative design process
CRD-2.H - Acknowledge code segments used from other sources.
  • CRD-2.H.1 - It is important to acknowledge any code segments that were developed collaboratively or by another source.
  • CRD-2.H.2 - Acknowledgement of code segment(s) written by someone else and used in a program can be in the program documentation. The acknowledgement should include the origin or original author’s name.