Build a Paper Computer and Explain It
You already know what each part does. Now you will build a whole computer from parts, run tasks on it and explain it to someone else.
For parents: a one-page guide — dinner questions and a game without a screen.
01Remember
Think first, then open the answer.
Which part is like a desk you work on, and forgets everything when the power goes off?
The working memory (RAM). It only remembers while there is power.
Which part keeps your photos when the computer is switched off?
Storage — like a cupboard that keeps things even without power.
Is a touchscreen an input or an output?
Both. It shows you pictures (output) and feels your finger (input).
02Story
When people want to invent a new machine, they often start with paper and a pencil. They draw boxes: “Information comes in here. It is worked on here. It is kept here. It comes out here.” Arrows show which way it goes.
Such a drawing is called a diagram. It is cheap: if you make a mistake, you simply cross it out. No electricity, no screws.
Today you will do exactly that — but with parts you can move around. Then we will check whether your machine works.
There is one more thing. When you explain to someone how something works, you understand it better yourself. That is why your second job is to explain.
03Worked example
Task: type the word “cat” and see it on the screen. Here are the parts it needs:
Input
The keyboard. Letters get into the computer with it.
Processing
The processor carries out the steps: “take in the letters and get them ready to show”.
Working memory (RAM)
While you work, the letters sit on the “desk”. Without it there is nowhere to work.
Output
The screen shows the word.
Did you notice? We did not use storage. We are not keeping anything for tomorrow — we only type and look. Storage is needed when you want something to stay after the power goes off.
04Try it now
1 · Predict
You want to draw a picture and find it again tomorrow. Which part cannot be missing? Choose before you check.
2 · Run: build the paper computer
Choose a task. Then tap a part in the bottom row and tap a place to put it in. Tap a part that is already placed to take it back. At the end press “▶ Run”.
Places (tap an empty place after you pick a part):
Parts (tap to pick):
3 · Change
Try these too:
- Build a computer for Task 1 and run it. Then remove the working memory and run it again. What is missing?
- Switch to Task 2. What must you change in the input and in the output? Can you remove the storage?
- Why is storage needed in Task 3 but not in Task 1?
05No screen: “Paper Computer”
You need: a sheet of A4 paper, 8 small pieces of paper (or cards), a pen and scissors (points down; if you are small, with an adult).
Draw five squares on the sheet and label them: INPUT, PROCESSING, WORKING MEMORY, STORAGE, OUTPUT. Draw an arrow from INPUT to PROCESSING, then to OUTPUT.
On the eight pieces, draw and label the parts: keyboard, mouse, microphone, processor, working memory, storage, screen, speaker.
Another person gives you a task. For example: “Draw a picture and keep it for tomorrow.” You put the parts in their places.
They check: “How does the picture get in? Where will you see it? What keeps it when the power goes off?” If a part is missing — add it.
Swap roles: now you give them a task.
06Make your own
You are now a Creator: you can not only know things, but also explain them and make them for others. Two jobs:
Explain it to someone
- Choose a person at home or in class.
- Show them your paper computer and explain at least three parts and why they are there.
- Ask them to give you a task. Can they spot which part is missing?
Make one for someone
- Make a paper computer for a younger child — a little brother or sister, a cousin or a pupil from a lower class.
- Use fewer parts (for example 4), bigger drawings and simple words.
- Do not write names, addresses or other personal things on the cards. Do not ask for money and do not advertise anything.
- Show the child how to play. Ask: “What was easiest? What was hardest?” Then make it better.
07What I learned
- A computer is built from parts with different roles: input, processing, working memory, storage, output.
- The same role can be done by different parts — it depends on the task.
- Working memory forgets without power. To keep something until tomorrow you need storage.
- When you explain something to someone else, you understand it better.
When a computer runs out of working memory, it slows down. How do you notice that too much has come at you at once?
Check yourself
1. A drawing is in the working memory, but there is no storage. The power goes off. What happens to the drawing?
2. Which part is an input?
3. Which part carries out instructions very fast?
It is yours when you can build a paper computer for a task and explain to someone at least three parts and why they are there. No points and no rankings — just a skill.
08I have a question
Do you still have a question? Write it here. It goes to your parent, not to strangers. Your parent confirms their e-mail first.
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·Sources
- Title: Build a Paper Computer and Explain It (DB-VK-13) · Author: Children's Library, East Accelerator Foundation · Source: original content, 2026 · Rights: CC BY-SA 4.0.
- School link: Bulgarian curriculum, Computer Modelling and Information Technologies, grade 5 — components of the computer system; input, output and input-output devices (Ministry of Education programme, in Bulgarian, checked 02.10.2026).
- Licence: CC BY-SA 4.0 · Children's Library, East Accelerator Foundation, 2026. You may share and adapt this lesson if you credit the author and keep the same licence. Learning is free forever.