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Computational Thinking and Algorithms

Notes and links to resources from the CPD workshop at National STEM Centre in York on 6th October

Pete Dring

Created by Pete Dring
last edited Oct 06 2014 by Pete Dring

These are the slides and notes from the CPD workshop at the National STEM Centre in York on 6th October for Primary Computing.

Feel free to adapt and re-use the presentation for any other training event if that’d be helpful, but most people would find the notes and links to resources mentioned during the workshop more useful. They can be accessed here:

Thanks for everyone who came along today. I hope these are useful.

Level: Beginner

Duration: 1 hour

Teaches: The slides go through each aspect of Computational Thinking with real-world examples and scratch examples.

The unplugged activity is a competition where students work in teams to fetch binary instructions, convert the binary to decimal and then turn the instructions into a simple image.


Computers can send binary information by sending:

  • electricity down a wire

  • light down a fibre

  • radio signals through space It doesn’t really matter how the data travels, the computer only cares about the fact that it receives either 0s or 1s


Whole images can be made up of individuals dots (pixels). Computers store the information for each pixel separately. In this activity, we fetched each instruction one at a time and built up the image pixel by pixel.

Algorithmic Thinking

Students had to follow the algorithm for converting from binary to decimal and then follow the instructions to turn those numbers into an image


At the end of the activity, when we discussed how we could speed up the game, we learnt how we could judge whether one computer is faster than another in terms of:

  • number of cores (e.g. quad core is like 4 people fetching instructions at once)

  • clock speed (e.g. 2Ghz compared to 1Ghz is like a person running twice as fast to get an instruction)

  • bit width (e.g. a 64bit processor can deal with twice as much info per instruction as a 32 bit processor which is like collecting two instructions per person per trip rather than one)


When converting from binary to decimal, we discussed how the algorithm for understanding the numbers is the same. For decimal, each digit is worth 10x as much as the one to its right. In binary, each digit is worth 2x as much as the one to its right.

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