Computer Science 1 – Unplugged Thinking

Computer Science 1 – Unplugged Thinking

At Key stage 1, children should be able to:

  • understand what algorithms are, how they are implemented as programs on digital devices, and that programs execute by following precise and unambiguous instructions

At Key Stage 2, children should be able to:

  • use logical reasoning to explain how some simple algorithms work and to detect and correct errors in algorithms and programs

These activities can be used as standalone sessions  and are also linked to the CS 2 strand as an introduction to the programming activities where appropriate. The activities have been chosen to address  the computing concepts to be taught in the primary curriculum.


EYFS – Instructions

Can the children tell each other instructions on how to complete certain class rules within the class? What specific instructions/language do we need to do to make sure our friend follows our new class rules?

E.G Tidying up when you have made a mess, lining up.

What are the instructions for lining up quietly?

Stand up straight

Walk to back of line

Face the front

What are the instructions for tidying up?

Pick up object with your hand

Place object into box.

Children role play as a teacher and give these instructions through phones to their friends. Did their friend follow your exact instructions?


Vocabulary grid, picture aids.



*Jam sandwich algorithm

Create an algorithm (a precise set of instructions or rules to achieve an outcome or solve a problem) to instruct a pretend robot (teacher) to make a jam sandwich.

*Patterns unplugged

This is an unplugged activity in which pupils work in pairs to spot patterns in sets of pictures of objects and think of general statements to describe these things e.g. elephants, cats, cars.



*Crazy character algorithms

By teaching this short unplugged activity your pupils will create a set of instructions on how to draw a crazy character and so start to understand what algorithms are.

*Sharing sweets algorithms

Children will share between different numbers of friends and then compare the similarities and differences between their algorithms. In doing this they are using pattern to create a general rule for sharing.

*Spelling rules algorithms

Pupils will explore the graphemes for a particular phoneme (its spelling rules), as chosen by you. They start to understand what algorithms are, and use logical reasoning to predict the behaviour of simple algorithms.

*Beebots algorithm into programming

Pupils create sequences of instructions (an algorithm) to draw the shape of a numeral e.g. 3.



*Shapes and Crystal Flowers

Children write algorithms to create 2D shapes, then write a program to execute their algorithm

2D shape drawing debugging

In this activity pupils will follow an algorithm to draw pictures constructed from 2D shapes. The algorithms they follow will include errors and pupils will use logical reasoning to detect and correct these.

Introduction to decomposition

This is an unplugged activity in which pupils create hand clapping, hand tutting or hand jive sequences of movements. Pupils break the sequence of actions down into parts and in so doing are decomposing

Patterns unplugged

In this unplugged activity pupils spot patterns in pairs of similar recipes to identify common steps that they can reuse in new recipes that they create.




*Playground games algorithms

Pupils learn how to use a flow chart by trying to work out what playground game it describes.

*Getting up algorithm

Writing an algorithm focussed around getting up and getting to school.



*Introduction to variables

In this activity pupils learn why variables are needed, how they are created, how they store data, and how this data may be used by a computer program as it runs.


Logical number sequences

In this activity pupils explain the rule for a number sequence and predict which number(s) comes next. In doing so, they extend their knowledge of simple rule based algorithms.


Logical Reasoning

The emphasis of this activity is on pupils using logical reasoning to solve the puzzles – pupils have to explain to their partner how they have worked out each number they add to the sudoku grid




Exchange sort investigation

In this module pupils investigate all the possible ways of comparing two cards in a list such as starting with the end cards and working into the centre or comparing pairs next to each other starting on the right of the list.


Abstraction unplugged

Pupils create simple models from modelling dough or draw quick sketches for a partner to guess what they are representing. In doing so they learn they are ignoring unimportant details and only including that which is most important, and in so doing are abstracting.