Teaching Computational Thinking Without a Computer Laboratory: Practical Strategies for Ghanaian Teachers

In many Ghanaian schools, a Computing lesson happens with one laptop shared by a whole class, a projector that may or may not work, or no computer at all. NaCCA's own Computing curriculum acknowledges the reasons: the high cost of equipment, poor connectivity and unreliable power. It would be easy to conclude that computing cannot be taught properly without a laboratory. That conclusion is wrong, at least for one of the most important parts of the subject. Computational thinking, the way of reasoning that sits underneath all programming, can be taught with chalk, paper, a set of cards and a well-planned activity.

What computational thinking is, and what it is not

The computer scientist Jeannette Wing popularised the term in a short 2006 essay, arguing that computational thinking is a fundamental skill for everyone, not only for computer scientists (Wing, 2006). It is not the same as using a computer, and it is not the same as programming. It is a way of approaching a problem so that a solution can be carried out step by step, by a person, a machine or both.

Teaching materials commonly describe it through four ideas. BBC Bitesize calls them the four cornerstones.

Decomposition: breaking a big problem into smaller parts

Preparing a class for the 6 March Independence Day march-past is a big task. Broken down, it becomes smaller jobs: checking uniforms, choosing a leader, practising the salute, learning the route and agreeing a practice timetable. Each small job is easier to plan and check than the whole.

Pattern recognition: spotting what repeats

Kente cloth is built from repeating blocks of colour and shape. A learner who notices that a strip repeats "gold, green, gold, red" can predict what comes next without being told. The same skill helps in Mathematics, when learners notice that every number in the 5 times table ends in 0 or 5.

Abstraction: keeping what matters and leaving out the rest

A map drawn to show a visitor the way from the school to the market does not need every house, tree and kiosk. It needs the junctions, a few landmarks and the direction to turn. Deciding what to leave out is abstraction, and it is harder than it sounds.

Algorithms: writing clear, ordered steps

An algorithm is a precise sequence of steps for carrying out a task. Washing hands at a Veronica bucket is a good example: open the tap, wet your hands, close the tap, apply soap, scrub every part of both hands, open the tap, rinse, close the tap, dry your hands. Change the order or leave out a step and the result is different.

Why "unplugged" teaching is worth taking seriously

Teaching computing concepts without computers is often called "unplugged" learning. The best-known collection of such activities, CS Unplugged, was developed at the University of Canterbury in New Zealand and is free to use.

The approach has research behind it, with some important limits. A 2023 systematic review examined 49 studies of unplugged activities in primary and secondary education. Its meta-analysis of 13 of those studies found a large overall positive effect on learners' computational thinking skills, and board and card games were the most common type of activity (Chen et al., 2023). The authors are also clear about the limits: the meta-analysis rests on a small number of studies, and the effect of learners' socioeconomic background has barely been studied. That second point matters for Ghana. The evidence is encouraging, but it was not gathered in Ghanaian classrooms, and teachers should watch carefully how their own learners respond.

Unplugged activities are also a foundation, not a replacement for computers. NaCCA's Computing curriculum for senior high school includes a full strand on computational thinking, covering algorithms, data structures and app development, and it describes computational thinking as involving "the implementation of solutions using automation, programming and computer systems" (NaCCA, 2023). Learners who meet these ideas early, through cards and paper, arrive at that stage with a head start. They will still need real devices when they get there.

Five classroom activities

The activities below are designed for Basic 4–6 and need only paper, chalk, markers or cards. Each takes between 30 and 40 minutes and works with groups of four to six learners.

Activity 1: Program the robot (instruction cards)

Ideas practised: algorithms, sequencing, repetition.

Materials: A 4 × 4 grid drawn on the floor with chalk, or on a large sheet of paper on a desk. A bottle top or small toy as the "robot". A set of instruction cards for each group: Forward (move one square in the direction the robot is facing), Turn left and Turn right (turn on the spot without moving). Number cards 2, 3 and 4.

How it works:

1. Label the columns A to D and the rows 1 to 4. Place the robot on A1, facing towards row 4. Draw a star on C3.

2. Each group lays its cards in a line to make a "program" that will take the robot to the star.

3. One learner plays the computer and follows the cards exactly, one at a time, without guessing what the group meant.

4. One correct program is: Forward, Forward, Turn right, Forward, Forward. The robot moves to A2, then A3, turns to face column D, then moves to B3 and C3.

5. Now introduce the number cards. A "2" placed before Forward means "do this twice", so the same program becomes: 2 Forward, Turn right, 2 Forward. Ask: which version is shorter? Which is easier to check?

Extend it: Add "rocks" on squares the robot must avoid, or ask groups to find two different programs that both reach the star.

Activity 2: The Veronica bucket algorithm (paper algorithms)

Ideas practised: algorithms, precision, testing.

Materials: Paper and pencils. A real or imaginary Veronica bucket.

How it works:

1. In pairs, learners write step-by-step instructions for washing hands at a Veronica bucket.

2. Pairs swap their instructions with another pair.

3. One learner acts out the instructions they received exactly as written, nothing more and nothing less. If the instructions never say "open the tap", no water comes out.

4. The class discusses the steps that were missing or in the wrong order. Gaps to look out for include opening and closing the tap, and drying the hands.

Why it works: Learners discover for themselves that a computer, like the learner acting it out, does only what it is told. Vague instructions produce wrong results.

Activity 3: Put it in order (sequencing)

Ideas practised: sequencing, decomposition.

Materials: Strips of paper, each with one step of a familiar process written on it. Planting maize works well: clear the land, choose good seeds, dig the holes, put the seeds in the holes, cover the seeds with soil, water the soil.

How it works:

1. Give each group the strips, shuffled.

2. Groups arrange them in order and explain their choice.

3. Then ask the more interesting question: which steps could swap places without changing the result, and which could not? Choosing the seeds and digging the holes could happen in either order, or at the same time if two people share the work. But the seeds cannot go into holes that have not been dug yet.

Why it works: Learners see that some steps depend on others and some do not. This is an early idea that later helps them understand how programs, and the people who write them, organise work.

Activity 4: Find the bug (debugging)

Ideas practised: debugging, logical reasoning.

Materials: The grid from Activity 1. A set of instructions that contains a mistake.

How it works:

1. Give each group a "broken" program, such as: Forward, Forward, Turn left, Forward, Forward. The robot starts on A1 facing towards row 4, and the target is still C3.

2. Groups act it out. After the second Forward the robot is on A3, but Turn left points it towards the edge of the grid, so the next Forward walks it off the board.

3. Groups find the first wrong step and fix it. Here, Turn left should be Turn right.

4. Ask each group to write a broken program of its own for another group to fix.

Why it works: In computing, a mistake in a program is called a bug, and finding and fixing bugs is normal, everyday work. Treating mistakes as puzzles to solve, rather than as failures, builds the confidence learners need.

Activity 5: Sort it out (group problem-solving)

Ideas practised: algorithms, pattern recognition, collaboration.

Materials: Eight cards per group, each with a different number between 1 and 50.

How it works:

1. Each group lays its cards face up in a row, in random order.

2. The rule: learners may only compare two neighbouring cards at a time. If the left card is bigger, swap them. Then move one place to the right and compare the next pair.

3. When they reach the end of the row, they start again from the left. They stop when they can go through the whole row without making a single swap.

4. One learner counts the swaps. Groups compare their counts and discuss: why did some groups need more swaps than others? What do you notice about where the largest number ends up after the first pass through the row?

Why it works: This is a real sorting method used in computing, often called bubble sort. Learners follow an algorithm, notice a pattern (after each pass, the largest remaining number has moved to its correct place at the end) and work as a team.

Assessing computational thinking without a computer

These activities are easy to assess by watching and listening. While groups work, look for three things:

• Breaking down: Can the learner split a task into smaller steps without help?

• Precision: Are the learner's instructions exact enough for someone else to follow without guessing?

• Debugging: When something goes wrong, can the learner find the step that caused it and explain the fix?

A quick exit task works well at the end of a lesson: give each learner a short, broken set of instructions on a slip of paper and ask them to circle the mistake and write the correction.

Fitting this into the timetable

These activities can sit within Computing lessons, but they are not limited to them. Activity 5 works in Mathematics, Activity 2 connects with Science lessons on personal hygiene, and Activity 1 develops the precise language learners need in English. All five develop two of the core competencies named in Ghana's standards-based curriculum: critical thinking and problem-solving, and communication and collaboration (NaCCA, 2019). Before using an activity, check the indicators in your own scheme of learning and say clearly in your lesson note which one the activity supports.

Common pitfalls

• Playing the game but skipping the discussion. The learning happens when learners explain what went wrong and why. Leave time for it.

• Fixing the problem for the learners. Resist the urge to correct their cards. Ask questions instead: "Where is the robot now? Which way is it facing?"

• Giving long, complicated instructions. Start small. A 3 × 3 grid with two cards is a perfectly good first lesson.

• Calling it "just a game". Name the idea each time: "You have just written an algorithm." "That was decomposition." Learners should know what they are learning.

Conclusion

A computer laboratory is valuable, and Ghanaian schools deserve better access to devices. But the absence of one is not a reason to postpone computational thinking. With a grid drawn in chalk, a handful of cards and a willingness to let learners make and fix mistakes, any teacher can begin building the habits of mind that programming, and much else, depends on. For a discussion of how AI tools fit into Ghanaian classrooms, see Artificial Intelligence in Ghanaian Basic Schools.

Try this next week: Run Activity 1 in your next Computing lesson, starting with a 3 × 3 grid and only the Forward and Turn right cards. Keep the last ten minutes for each group to explain one mistake they made and how they fixed it.

References

• BBC Bitesize. What is computational thinking? Introduction to computational thinking, KS3 Computer Science. bbc.co.uk

• Chen, P., Yang, D., Metwally, A. H. S., Lavonen, J. and Wang, X. (2023). Fostering computational thinking through unplugged activities: A systematic literature review and meta-analysis. International Journal of STEM Education, 10, 47. https://doi.org/10.1186/s40594-023-00434-7

• CS Unplugged. University of Canterbury, New Zealand. csunplugged.org

• National Council for Curriculum and Assessment (2019). English Language Curriculum for Primary Schools (Basic 1–3), Core Competencies. Ministry of Education, Ghana. PDF

• National Council for Curriculum and Assessment (2023). Computing Curriculum for Secondary Education (SHS 1–3). Ministry of Education, Ghana. PDF

• Wing, J. M. (2006). Computational thinking. Communications of the ACM, 49(3), 33–35. https://doi.org/10.1145/1118178.1118215