Computer Organization & Systems
What's really happening beneath your code: bits, memory, and how C becomes electricity.
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Big Idea
How Computing Works
Grade bands
K-2 · 3-5 · 6-8 · 9-12
AI literacy pillar
How AI works · Ethics
Lesson overview
What's really happening beneath your code: bits, memory, and how C becomes electricity. This module climbs from an everyday intuition to the real mechanism, then names the Stanford course it descends from.
Teacher script · ~45 min
- 0–5
Hook
Underneath every photo, song, and message is a long string of 1s and 0s: bits, each a tiny on/off switch. Numbers, letters, colors are all just agreed-upon codes over bits. The computer never sees 'cat'; it sees switches. Understanding that demystifies the whole machine.
- 5–15
Explore
Students do the activity in pairs: Number 8 cups in a row. Put a note in cup 3 saying 'see cup 6.' Put candy in cup 6. You just followed a pointer.
- 15–30
Explain
The C you write is translated into 'assembly': a handful of dead-simple instructions the chip physically runs: load this box, add these, jump there. Seeing this layer explains why some code is fast and some slow, why memory layout matters, and how bugs corrupt things they 'shouldn't.'
- 30–40
Connect to the summit
Show students this is the real thing professionals build: CS107, the real thing. What's really happening beneath your code: bits, memory, and how C becomes electricity.
- 40–45
Check
Run the formative check below. Anyone who can explain a key term in their own words has it.
Student activity
Number 8 cups in a row. Put a note in cup 3 saying 'see cup 6.' Put candy in cup 6. You just followed a pointer.
Slides
Formative check
- 1.In your own words, what is "Bit / byte"? (Looking for: A bit is one on/off switch; a byte is eight of them, the basic storage unit.)
- 2.In your own words, what is "Pointer"? (Looking for: A value that holds the memory address of some other data.)
- 3.In your own words, what is "Stack vs heap"? (Looking for: Two regions of memory: the stack for short-lived calls, the heap for data you manage.)
Carry-away concepts
- Bit / byte
- A bit is one on/off switch; a byte is eight of them, the basic storage unit.
- Pointer
- A value that holds the memory address of some other data.
- Stack vs heap
- Two regions of memory: the stack for short-lived calls, the heap for data you manage.
- Assembly
- The low-level instructions a CPU directly executes, just above raw machine code.
From the summit · the Stanford source
You learn how data is represented in bits, how C maps to assembly and memory, and how to write programs that respect the real machine.
This module descends from CS107 at Stanford. Students who climb the full ladder arrive here.