You’ll notice a brand-new activity type sprinkled throughout the AP CSA (Cortado) lessons: Explorations. They’re short, highly structured activities built around the PRIMM model and designed to give students deliberate practice reading and tweaking code before they write their own.
What’s PRIMM?
PRIMM is a programming-instruction framework created by Dr. Sue Sentance, who leads the Raspberry Pi Computing Education Research Centre. It is a five-step framework—Predict, Run, Investigate, Modify, Make—that guides students from reading and anticipating what a short program will do, through running and dissecting it, to making targeted tweaks and finally creating something new. By postponing “from-scratch” coding until the last step, PRIMM builds conceptual understanding and confidence first, making it easier for students to reason about and adapt code (a must-have skill in the generative-AI era).
Stage | Student Actions |
Predict | Students read through a program and predict what it will do. |
Run | Students run the program to test those predictions. |
Investigate | Guided by investigative questions, students study the program and reflect on its structure and functionality. |
Modify | Students modify the program to alter the outcome or add functionality. |
Make | Students extend the idea into a program of their own. |
By walking through PRIMM, students build conceptual understanding first, lowering the “blank-screen anxiety” that often comes with programming from scratch.
Why Reading & Modifying Code Matters More Than Ever
Generative-AI assistants can now spit out a dozen Java methods in seconds—but the real skill is deciding whether that code is correct, secure, and appropriate. Explorations give students repeated opportunities to:
read and digest unfamiliar code
reason though structure and logic and their outcomes
make edits to fit a specific context
Those habits are exactly what tomorrow’s developers (and today’s CS students) need in an AI-powered workflow.
Meet Investigate.txt
Every Exploration activity includes an Investigate.txt file. Think of it as a digital lab notebook:
Prompts guide students to record predictions, questions, discoveries, and next steps.
Almost all of them aren't autograded — the value is in the formative reflection.
Teachers can read the file to check conceptual progress.
As you begin your first Exploration activity, model one full PRIMM cycle early on and show students how they can record their observations in Investigate.txt. After that, choose the workflow that fits your class: optional / required, physical notebook, individually / in pairs / as a class, etc.
Examples vs. Explorations—A Quick Clarification
Examples | Explorations |
Complete sample programs that appear right after the lesson video. | Tightly scaffolded PRIMM tasks embedded within the lesson. |
Encourage open-ended poking around and optional guiding questions. | Follow the four PRIMM phases in order with explicit prompts (Make occurs in the activities that follow). |
Great for “look how this works” demos, group building or debugging, or fast experimentation. | Purpose-built to strengthen code-reading and modification skills. |
No auto-graded elements. | Most contain auto-grader test cases for the Modify tasks. |
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