1. What are algorithms?
  2. What are they used for?
  3. How do we write them?
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Making the tea


Click on the Word icon above to download the file above and open it in word. Can you rearrange the instructions to make a cup of tea?

Extension Activity

  • Can you think of any problems with the set of instructions above?
  • When might they not work?
  • What improvements can you think of?

Credit: Activity sourced from here.

Key Definition – Algorithm

ic_action_edit An algorithm is a set of step-by-step instructions used to solve a problem. They are used by both human beings and computers.


Algorithms for humans

Computers require algorithms in order to function, however humans use algorithms too! Here are some common algorithms written for humans to follow.[Best_Wordpress_Gallery id=”1″ gal_title=”Human Algoriithms”]


Can you think of any more common algorithms designed for humans to follow?


Algorithms for computers

Algorithms designed for computers are written in a programming language. Programming languages are usually text-based or block-based.

They must be written in such a way that both the computer and the programmer can read the code.

Your turn. Have a go!


Click on the robot above to see if you can code the robot to turn on the lights.


Let’s go shopping!

An alien has landed on earth and you have decided to send him on an important mission – to do your weekly shopping down at the supermarket! You have been given a shopping list. The alien has never been shopping before – can you write a set of instructions for it to do the shopping for you!


Your algorithm must be:

  • Step-by-step.
  • Unambiguous – Each step must be completely clear and specific.

The class will now get together to compare each other’s algorithms.

  • Can you think of any problems with other people’s algorithms?
  • Can you think of any improvements that you might make to your own algorithm?







Have you…

  • Edited the ‘making the tea’ word document?

  • Created your ‘Let’s go shopping’ algorithm and added it to your learning log?

  • Completed the extra topics on the learning log?

(Click here to access quizmaster)

Useful introduction flash video (sound required)

BBC Bitesize – What is an algorithm video