Grandma and Grandpa’s Machines: a class pack
1. Overview: the lessons in the track
| ID | Lesson | Level | Grades | For parents |
|---|---|---|---|---|
| DB-MD-01 | Grandpa’s Machine: Pravetz and the 8-bit World | Explorer | 4–5 | parent guide |
| DB-MD-02 | IBM and Pravetz: Two Machines of One Era | Tinkerer | 5–6 | parent guide |
| DB-MD-03 | Why Do All Computers Look Alike? Standards | Tinkerer | 4–5 | parent guide |
| DB-MD-04 | The Singing Tape: How Games Were Loaded | Explorer | 4–5 | parent guide |
| DB-MD-05 | A Machine Museum in the Classroom | Creator | 5–6 | parent guide |
| DB-MD-06 | From the Valve to the Chip | Tinkerer | 5–6 | parent guide |
| DB-MD-07 | Grandma’s Radio | Creator | 5–6 | parent guide |
School curriculum link: none of the seven lessons claims one — this is extra reading. The lessons tell history and teach how a computer works; they do not replace a school subject.
2. What is in the pack
- Three plans of 45 minutes (pp. 2–4): A · form period (DB-MD-01) · B · interest club (DB-MD-04) · C · library (DB-MD-05). Each follows the eight steps of the lesson and has a “no screen” option.
- Worksheets (pp. 5–11) — one per lesson; only tasks that are already in the lesson. Children sign with initials or a star, not a name.
- Safety, counting without tracking, licence (p. 12).
- DB-MD-02 and DB-MD-03 run in the same eight steps; two such lessons can share one hour if you skip “Make your own”.
- DB-MD-06 and DB-MD-07 also run in the eight steps of the lesson; their materials are in the worksheets (pp. 10–11) and in the lessons themselves: for DB-MD-06 — a shoebox, an empty matchbox, a grain of rice, small cards, a ruler; for DB-MD-07 — paper, a pen, a small card.
3. Where it fits in school
Under Ordinance No. 13/2016, health, civic and environmental education is delivered in an integrated way, in the form teacher’s period (Art. 11) and in interest activities in the full-day organisation (Art. 12). These two slots are the natural place for extra material; the library is the third. Here the subject is the history of computers, not one of those areas, and the lessons are not approved by the Ministry of Education — use them as extra reading at the teacher’s discretion. (Quoted from the original text, State Gazette No. 80/2016; later amendments have not been checked.)
Works without internet: the simulators are built-in code and save nothing; rooms without computers use the “no screen” options.
Grandpa’s Machine: Pravetz and the 8-bit World
Goal
You will be able to tell what the Pravetz 82 is and write and run a two-line program on a simulator of an old computer.
Materials
a projector or one computer per pair (the simulator runs in the browser, no internet needed); paper and pencil; 4 paper strips per pair; the lesson and the parent guide.
Run of the lesson, minute by minute (the eight steps)
| Min | Step | What you do |
|---|---|---|
| 0–4 | 1 · Remember | Read the goal. Three questions: the four jobs every computer does; which memory forgets when the power goes off; what a bit is. Children think first, then you open the answer. |
| 4–10 | 2 · Story | Why “Pravetz”; what is inside the Pravetz 82 (6502 processor, 48 KB working memory, 12 KB ROM, 8-bit). Where sources disagree: 1982 or 1983; 1979 or 1980. The question: “Who wrote it, and how do they know?” |
| 10–15 | 3 · Worked example | Input → memory → processing → output: a line with a number is remembered, RUN runs it in number order. We number in tens. |
| 15–25 | 4 · Try it | Predict (PRINT without a number: instantly, waits for RUN, or an error?) → Run the green screen: 10 PRINT "ЗДРАВЕЙ", then RUN → Change: line 20 before line 10; insert line 15; “Switch off the power”. No names, addresses or phone numbers. |
| 25–29 | 5 · No screen | Read the three interview questions for a grandparent; children copy them to take home. Only if the older person would enjoy it; no photos or recordings without permission. |
| 29–39 | 6 · Make your own | Paper strips 10–40 in pairs: shuffle them, put them in order by number and read them aloud like a “computer”. A fifth strip numbered 25 — where does it go? |
| 39–43 | 7 · What I learned | “Check yourself” — three questions. Skill badge “I run a program in old BASIC”: no points, no rankings. |
| 43–45 | 8 · I have a question | Questions on paper, for the teacher, or through a parent. Press “We did the lesson” (p. 12). |
“No screen” option (room without computers)
Skip step 4. The teacher reads the story and writes the example on the board (10 PRINT "ЗДРАВЕЙ" → RUN). The time goes to the paper strips (step 6, up to 20 min): put them in order by number and read aloud like a “computer”; a fifth strip numbered 25. Questions aloud, by a show of hands.
How you will know it was learned
The child explains why, at RUN, the line with the smaller number runs first, and says what the working memory forgets when the power goes off. The badge is theirs once they write two numbered lines, run them and explain why they appear in that order.
A computer keeps its program as long as there is power. And you — what do you keep in your memory from Grandma and Grandpa’s stories? (a question to finish, not to grade)
The Singing Tape: How Games Were Loaded
Goal
You will be able to explain how sound on a tape carries zeros and ones, and sing and read one letter.
Materials
computers or a projector with sound (optional), paper and pencil; one more person to be the “tape recorder” (in pairs); the A–H table on the board; the lesson and the parent guide.
Run of the lesson, minute by minute (the eight steps)
| Min | Step | What you do |
|---|---|---|
| 0–3 | 1 · Remember | What a bit is and how many bits make a byte; what is forgotten when the power goes off; which things keep programs without power. |
| 3–10 | 2 · Story | A game on tape: LOAD "", a steady tone, then a “screech”. Zero is a short, higher sound; one is twice as long and lower; the computer only measures how long each sound is. A check number at the end. About five minutes for 48 KB. Where sources disagree: the speed (1500 bits/s or 171 bytes/s) and which sound is zero. |
| 10–15 | 3 · Worked example | The path of a letter: A → 65 → 01000001 → short, LONG, short, short, short, short, short, LONG → back into memory. |
| 15–25 | 4 · Try it | Predict → A. Sing a letter (switches; “Slowly”, then “Like a real tape”) → B. Catch the letter (secret letter A–Z) → Change (A and B; eight zeros against eight ones). Sound starts only after a click; “No sound” — blocks only. |
| 25–33 | 5 · No screen | Loading with voices in pairs: the “tape recorder” says “ee” = 0, “ooo” = 1 (first a steady “mmm”); the “computer” writes eight zeros and ones and finds the letter in the table. Swap roles; then three letters in a row. |
| 33–40 | 6 · Make your own | Your own code with three bits per letter (A = 000 … H = 111). A three-letter word, e.g. BAG: 001 000 110. “Sing” it; bonus: say how many long sounds there are — that is how an error is caught. |
| 40–44 | 7 · What I learned | “Check yourself” — three questions. Skill badge “I read the zeros in sound”: no points, no rankings. |
| 44–45 | 8 · I have a question | A question on paper or through a parent; “We did the lesson” (p. 12). |
“No screen” option (room without computers)
The whole hour can run without a computer: step 4 is replaced by step 5. The teacher “sings” a letter (short “ee” and long “ooo”), the class writes zeros and ones and finds the letter in the table on the board; then swap roles in pairs. Nothing is switched on.
How you will know it was learned
The child explains that the tape carries sound and the computer turns it into zeros and ones; says which sound is 0 and which is 1 in our tape recorder and why more zeros means faster reading.
The computer waited about five minutes and never complained. And you — what is it like to wait for something good? (a question to finish)
A Machine Museum in the Classroom
Goal
You will be able to write a short, clear label for an old object, explain it to someone else and set up a small exhibition.
Materials
3 objects per child or group — brought in advance, only with the owner’s permission (an old watch, radio, calculator, book with drawings); cards; pens; a table; optionally a computer for the generator; the lesson and the parent guide.
Run of the lesson, minute by minute (the eight steps)
| Min | Step | What you do |
|---|---|---|
| 0–3 | 1 · Remember | What is written next to things in a museum; why we do not touch; is there something at home older than you. Answer in your head, then it is opened. |
| 3–7 | 2 · Story | Commodore PET 2001, January 1977: keyboard, screen and (in the first models) a tape recorder in one box; 4 KB of memory. A good label is like a good story: short, with one detail. |
| 7–12 | 3 · Worked example | A label with five parts: name · when · what it does · interesting · a question for the visitor. What we do not write: phone, e-mail, address, a stranger’s full name, a photo of a person. |
| 12–19 | 4 · Try it | Predict (short or long label for 3rd grade?) → Run the generator (example “Commodore PET”, “floppy disk” or your own object) → Change: “for a younger child” mode, 25 words at most. Printing is on your own computer. |
| 19–33 | 5 · No screen | Exhibition: 3 objects, a handwritten label for each. Rule: we look, we do not touch. The child is the guide and tells it without reading. Ask: “What was most interesting? What did you not understand?” — the label is corrected. |
| 33–41 | 6 · Make your own | Explain to someone else: one object for two minutes, without reading. Make for someone: a small tour of three objects with labels for a younger child, grandma or grandpa. No money, no advertising, no personal data. |
| 41–44 | 7 · What I learned | “Check yourself” — three questions. Skill badge “I make labels and explain”: no points, no rankings. |
| 44–45 | 8 · I have a question | A question on paper or through a parent; “We did the lesson” (p. 12). |
“No screen” option (room without computers)
Skip the generator (step 4): labels are written by hand on cards, as in step 5; the Commodore PET example is read from the story.
How you will know it was learned
The label is short, with a name and a question, and no personal data. The child explains the object for two minutes and another person can retell it.
Every old object keeps the memory of people who used it. Who in your family learned something that you do every day? (a question to finish)
Grandpa’s Machine: Pravetz and the 8-bit World
Initials or a star: ☆ Grade:
1. A program on paper
Write one line on each strip. Shuffle them, put them in order by number and read them aloud — like a computer.
Add a fifth strip numbered 25. Between which two strips does it go?
Which line runs first — the one with the smaller or the larger number?
Which memory forgets the program when the power goes off — the working memory or the storage?
2. Interview a grandparent (only if they would enjoy it)
If there is no grandparent nearby — another adult you know. If they do not remember or do not want to talk, stop and say thank you. Do not photograph or record without permission. The story is not posted online.
Did you see a computer when you were little? Where was it and what did people do with it?
What was it called? What did the screen and the keyboard look like?
Have you heard of Pravetz? Where did you come across it?
IBM and Pravetz: Two Machines of One Era
Initials or a star: ☆ Grade:
1. A timeline
Draw a straight line across the sheet (easier with two A4 sheets taped together) and divide it into four parts: 1981 · 1983 · 1984 · 1985–86. Place:
- 12.08.1981 — IBM PC 5150 (Intel 8088 processor)
- 08.03.1983 — IBM PC XT (Intel 8088)
- August 1984 — IBM PC AT (Intel 80286 processor)
- Pravetz 16 (Intel 8088) — at 1984 and at 1985–86, with a “?” because the sources disagree
Colour all machines with an 8088 processor in one colour. Which are they?
Which one stays uncoloured?
2. Invent two machines of your own
Name: Year:
Processor: Memory:
Name: Year:
Processor: Memory:
What must be the same for one game to run on both?
Why Do All Computers Look Alike? Standards
Initials or a star: ☆ Grade:
1. Plug hunt — looking only
We only look. Wall sockets are not touched and nothing is put into them, even if they are off. We look only at devices and cables that are not plugged in. We open nothing. Always with an adult.
| What the end of the cable looks like (draw it) | How many I found |
|---|---|
Which kind is the most common?
Draw the wall socket from memory (looked at from a distance):
2. Three funny devices and one common end
Invent three devices (for example a kettle for dolls, a lamp for a hamster, a clock for fish): · ·
Draw one common cable end for all of them:
What must the makers agree on? Shape: Power: Language:
The Singing Tape: How Games Were Loaded
Initials or a star: ☆ Grade:
1. You are the computer
Listen to eight sounds (“ee” = short, 0; “ooo” = long, 1) and write the zeros and ones. Then find the letter in the table.
1: letter:
2: letter:
3: letter:
| A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|
| 01000001 | 01000010 | 01000011 | 01000100 | 01000101 | 01000110 | 01000111 | 01001000 |
2. My tape for three letters
| A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|
| 000 | 001 | 010 | 011 | 100 | 101 | 110 | 111 |
My three-letter word (between A and H):
Its code:
“Sing” it to another person: first a steady “mmm”, then a short “ee” for 0 and a long “ooo” for 1.
Bonus — the check number. Long sounds I sang: My friend counted: Same? ☐ yes ☐ no
3. In your own words
Why did a 48 KB game take about five minutes to load?
A Machine Museum in the Classroom
Initials or a star: ☆ Grade:
1. A label for an object
We do not write on the label: phone, e-mail, address, a stranger’s full name, a photo of a person. Keep it short, in words a younger child understands.
Name:
From when (a year or “around”):
What it does:
Interesting:
Question for the visitor:
Name:
From when (a year or “around”):
What it does:
Interesting:
Question for the visitor:
2. Explain to someone else
The object I chose: I explained it to (a role, not a name):
What will they repeat to someone else?
3. Make for someone
Who the tour is for (a younger child, grandma, grandpa):
Three objects: · ·
What would they change, in their opinion?
No money, no advertising, no personal data. Objects only with the owner’s permission.
From the Valve to the Chip
Initials or a star: ☆ Grade:
1. The timeline
The cards are: vacuum tube · transistor · integrated circuit · Intel 4004 (the first microprocessor) · today’s chip. Put them in order from the oldest to the newest and write the year (or “around”).
| Order | Which card | Year |
|---|---|---|
| 1 | ||
| 2 | ||
| 3 | ||
| 4 | ||
| 5 |
What do the tube, the transistor and the chip have in common?
2. How much space? — no screen
The box is “the tube”, the empty matchbox (no matches) is “the transistor”, the grain of rice is “the chip”. These are not the real sizes — just a model. Keep the rice away from very small children.
All three switch. What changes from the box to the grain?
I measured the grain: length mm × width mm ≈ mm². The Intel 4004 die is about 12 mm².
3. A calculation about space
ENIAC took up about 28 m², and the 4004 die is about 12 mm². 28 m² = mm². Then: ÷ 12 ≈ .
Being honest about the calculation: we compare only space, not power — the two machines are not equally powerful.
4. Explain to someone else · Make for someone
I told the road from the valve to the chip in three sentences to (a role, not a name): They retold it: ☐ yes ☐ no
I made a timeline with four small cards (tube · transistor · integrated circuit · chip) for ☐ a younger child ☐ grandma ☐ grandpa. What would they change?
No money, no advertising, no personal data. Safety: an old radio or television is not opened, not switched on and not taken apart — even when unplugged. We look only from the outside and only with an adult.
Grandma’s Radio
Initials or a star: ☆ Grade:
1. A talk with grandma or grandpa (only if they would enjoy it)
Ask gently: “Would you like to tell me about the radio you had when you were little?” If the answer is “no” — say thank you and stop. If there is no grandparent nearby or they have no such radio — you can ask another adult or draw a radio from a picture in a book. Write down only the answers, not the names. Do not push anyone to tell more than they want.
Where did the radio stand?
What did you listen to most?
What was the best thing?
2. A plate for a radio
We do not write on the plate: names of people, an address, a phone number, an e-mail, a photo of a person.
Name (what it is: “valve radio”, “small radio”):
Year (a year, “around” or “not sure exactly”):
Where it is from (no address and no name of a person):
What it played: ☐ news ☐ music ☐ stories ☐ sport ☐ the weather
Memory (one short one, no names):
Check: ☐ it has a name ☐ it has a year or “not sure exactly” ☐ it says where it is from ☐ it says what it played ☐ it is short ☐ it has no personal data
I read the plate to grandma or grandpa and asked: “Was it like this?” ☐ I fixed it ☐ it was right
3. Explain to someone else · Make for someone
I told about the radio (what it was, what it played, why people listened to it) to (a role, not a name): What will they repeat to someone else?
I made a plate for ☐ grandma ☐ grandpa ☐ a younger child — for their radio or for an invented one. What would they change?
No money, no advertising, no personal data. Safety: an old radio is looked at from the outside only — it is not opened and not switched on; even when unplugged, there are parts inside that keep electricity. A heavy or fragile radio is moved only by an adult.
Safety, counting and licence
4. Safety (per the library’s framework)
- Electricity. Nothing is plugged in during these lessons. Do not open an old computer, television, radio, tape recorder or charger: an old picture-tube screen can hold dangerous voltage even when unplugged. Look at them from the outside only, with an adult. Wall sockets are not touched and nothing is put into them.
- An old radio (DB-MD-06, DB-MD-07). It is not opened, not switched on and not taken apart — even when unplugged: there are parts inside that keep electricity after it is switched off. Glass tubes break. We look at it from the outside only and only with an adult; a heavy or fragile radio is moved only by an adult. Lesson DB-MD-06 has no wall sockets, no batteries and no tools.
- The size game (DB-MD-06). The matchbox is empty, with no matches; the grain of rice stays away from very small children.
- Sound (DB-MD-04). The sound is quiet and starts only after a click; turn the volume down; there is a “No sound” option.
- Network and data. The simulators run inside the page and save nothing. Children do not write a name, address, school or phone number. The only form is “I have a question”: the child writes the question without personal data, the parent gives an e-mail and consent. Worksheets use initials or a star.
- Objects and people. Objects for the exhibition — only with the owner’s permission; nothing valuable, fragile, sharp, hot, no medicines, documents or personal photos. Interview a grandparent — only if they would enjoy it; no photos or recordings without permission; the story is not posted online. A radio plate (DB-MD-07) has no names of people, address, phone number, e-mail or photos of people.
- Sun and water are not part of this track.
If something frightens you — tell an adult you trust.
5. Counting without tracking: “We did the lesson”
We do not ask who used the pack. The button for each lesson adds +1 to a combined counter (day × lesson), with no names, addresses or identifiers. Write the number of children, the grade and the town on paper for yourself — they are not sent anywhere.
DB-MD-01 · Grandpa’s Machine: Pravetz and the 8-bit World
DB-MD-02 · IBM and Pravetz: Two Machines of One Era
DB-MD-03 · Why Do All Computers Look Alike? Standards
DB-MD-04 · The Singing Tape: How Games Were Loaded
DB-MD-05 · A Machine Museum in the Classroom
DB-MD-06 · From the Valve to the Chip
DB-MD-07 · Grandma’s Radio
6. Licence and publisher
The pack and the lessons are under CC BY-SA 4.0: you may share and adapt them, crediting the author and keeping the same licence. The facts in the lessons are retold from Wikipedia (CC BY-SA 4.0), Sinclair Wiki (CC BY-SA 3.0, in DB-MD-04), the pravetz.info virtual museum, A.Museum (© amuseum.bg — facts only), EUR-Lex, the Nobel Prize site (nobelprize.org) and Computer History Museum (in DB-MD-06) and Radio Bulgaria / BNR (in DB-MD-07); details are in the “Sources” section of each lesson. Apple, ZX Spectrum, Sinclair, Oric, IBM, Intel, Texas Instruments and Fairchild are company names and trademarks of their owners; “Pravetz” is a brand name — they are mentioned only to make clear which machine is meant.
Publisher: East Accelerator Foundation · host: kagami.bg (KAGAMI Ltd.) · free, no ads.