The Everything Educator
Hands typing on a laptop with lines of code in a terminal window

December 7 to 13

The week of December 9

Computer Science Education Week lesson: write exact steps, no computers needed

A free, no prep unplugged lesson for grades 2 to 8: students write exact steps and a partner follows them literally. Fits CS Education Week and the Hour of AI.

Grades
2 to 8, with changes for younger and older
Time
30 minutes
Prep
None. Project this page or read from it.
You need
Paper and pencil for each pair of students, A whiteboard or chalkboard and a marker for the teacher

What it is

Computer Science Education Week, or CSEdWeek, is held every year during the week of Grace Hopper's birthday, December 9. Hopper was born in 1906, and csedweek.org describes her as a rear admiral in the U.S. Navy and a computer pioneer. In 2026 the week runs from Monday, December 7 through Sunday, December 13.

The first CSEdWeek was launched by ACM on December 6 to 12, 2009. In 2013 Code.org organized the week around a new idea, the Hour of Code, and that first Hour of Code week reached over 15 million students. Since 2020 the Computer Science Teachers Association (CSTA) has coordinated CSEdWeek. Code.org now calls its Hour of Code the Hour of AI.

Computer science does not require a computer to learn. An algorithm is a step-by-step process to complete a task. A program is a set of instructions that a computer executes, and a bug is an error in a program. In this lesson students write an algorithm for a drawing, a partner follows it exactly, and the class finds and fixes the bugs.

How to run it

30 minutes, 6 steps. The time on the left is when each step starts.

  1. 0:00

    Be the robot

    4 min
    On the board

    The teacher is a robot. Rule: do exactly what the words say and nothing more. Instruction 1: Draw a house.

    You do
    • Stand at the board with a marker. Tell students you will follow instructions exactly as written and will not guess what anyone means.
    • Read Instruction 1 and freeze. Ask what is missing. Expect answers like where to start, how big, and which shapes.
    • Ask a student for Instruction 2. Whatever it is, do only what it says. If it says draw a square, draw a tiny square in a corner of the board.
    • Ask what the instruction forgot to say.

    Say: I am a robot. I cannot guess what you meant. I can only do what the words say.

  2. 4:00

    Five facts about CSEdWeek

    4 min
    On the board
    • CSEdWeek is held every year in the week of Grace Hopper's birthday, December 9. She was born in 1906.
    • Grace Hopper was a rear admiral in the U.S. Navy and a computer pioneer.
    • The first CSEdWeek was launched by ACM on December 6 to 12, 2009.
    • In 2013 the first Hour of Code week reached over 15 million students. Code.org now calls it the Hour of AI.
    • An algorithm is a step-by-step process to complete a task. A bug is an error in a program.
    You do
    • Read the five facts aloud, one at a time.
    • After the last fact, ask: where did the robot go wrong in the warm-up? Connect the answer to the definition of a bug.
  3. 8:00

    Write the algorithm

    7 min
    On the board

    Secret picture: a square wall, a triangle roof on top, a rectangle door in the middle of the wall, and a small circle in the top right corner of the page. Write numbered steps so another pair can draw this picture without seeing it. Do not draw the picture. Do not use the words house or sun. Write at least eight steps.

    You do
    • Pairs write numbered steps on paper in words only. Circulate and encourage them to say where each shape starts, how big it is, and which way each line goes.
    • Do not tell any pair what is missing. Missing details are the point of the next step.

    Say: Imagine your reader is a robot that has never seen a house or a sun.

  4. 15:00

    Run it like a computer

    7 min
    On the board

    Swap papers with another pair. One partner reads one step at a time. The other is the computer: draw only what the step says. If a step is unclear, do the smallest thing the words allow, or draw nothing. No guessing and no talking. When the steps end, compare the drawing with the secret picture on the board.

    You do
    • Make sure each pair has a paper that is not its own.
    • Remind the computers not to fix anything. A computer cannot ask what the writer meant.
    • When the drawings are done, show the secret picture by drawing it on the board in about 20 seconds. Pairs compare.
  5. 22:00

    Find and fix the bugs

    5 min
    On the board

    Get your paper back. Circle each step that caused a bug. Rewrite two of them so a computer could not misread them.

    You do
    • Pairs circle the bugs on their own paper and rewrite two steps.
    • Collect the kinds of bugs on the board. Expect: no starting point, no size, no direction, steps in the wrong order.
    • Ask two pairs to read a rewritten step aloud, and ask the class whether a robot could still misread it.

    Say: A bug is not a failure. It tells you where the instructions were not exact enough.

  6. 27:00

    Exit ticket

    3 min
    On the board

    Copy one step from today that was too vague. Rewrite it so a computer could follow it exactly.

    You do
    • Students answer on a scrap of paper and hand it to you at the door.

Discussion questions

Open an answer when you want it.

Why can't a computer just know what you meant?

A computer executes the instructions it is given and nothing more. If a step leaves out where to start, how big or which direction, the computer cannot fill in the gap, so the programmer has to.

Does the order of the steps matter? Give an example from today's drawing.

Yes. An algorithm is a step-by-step process, so changing the order changes the result. For example, drawing the door before the wall leaves nowhere to put it. Accept any specific example.

Where did most of the bugs in your first draft come from?

Usually from a detail the writer took for granted, such as a starting point, a size or a direction. Programmers often find bugs by running the steps exactly as written.

Exit ticket

Copy one step from today that was too vague. Rewrite it so a computer could follow it exactly.

A good rewrite names a starting point, a size and a direction. For example, "Draw a square" becomes "Put the pencil in the middle of the page. Draw a line 4 centimeters long going right."

Make it fit your class

Younger students

For kindergarten and grade 1, skip the writing. Students give the teacher one command at a time to walk to the door, such as forward or turn left. The teacher follows each command exactly and stops after each. After each mistake, ask what command would have fixed it.

Older students

For grades 9 to 12, add a rule: a step may use the word repeat. Students rewrite their algorithm so the repeated moves use repeat, then trade papers again. Ask whether the shorter version is easier or harder to debug, and why.

Where the facts come from

Image credits

Updated October 31, 2026