Category: algorithms

jump the frogs

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This activity is explained in further detail here ( and an on-line simulator) This works well, its a problem solving and pattern recognition activity. It will take most students some time to work this out, pupils that work this out should either assist others or start writing down the instructions to complete this problem for n frogs, that is 3 either side or 3 billion, the same method should work. Point them towards starting with one frog each side and then building up to 2, 3, 4 …Also, they should work out the maths to work out the minimum number of moves for n frogs. Explanation of the maths is here

jumping frogs

team dance…

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Pupils choose a theme, for example, ‘dino dance’, the teacher, for ease could decide on the same music for all, playing music to the whole class. Keep routines short – 30 seconds for example. The pupils will create their own short routine, with loops. They must note the sequence for their dance down on paper, in any notation. Groups can perform to each other and the watching groups must try and decompose their dance, describing it (noting on paper). They could then try and recreate the other groups dance…or not!

An activity such as this could be followed up by creating a longer routine with more avatars in software such as Yenka.

draw what I say

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The aim of this task is highlighting the importance of clear and precise instructions. Make the point that computers follow many simple instructions and will not fill in gaps or make assumptions like we do as humans.

Hand paper to each pupil. Pupils should draw what you say. No questions allowed, do in silence. Start with a simple shape. Pupils then hold up and show each other. Amusement may following. Then perhaps build up to a simple house or animal…

next pair pupils up to take it in turns to explain to each other their own simple drawings, repeating a couple times.

theme park ride

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Pupils design a log flume type theme park ride. First, draw a top-down view of the ride. Annotate with places where you would need some kind of sensor/gate to ensure each boat won’t crash into each other. Where will the belt lifts be on your ride? these are controlled by motor and will need turning on and off. Spraying water jets? sounds when in a tunnel? These will need turning on and off. Your task is to sketch your ride and then describe it as a flowchart. Pupils find it easier to describe the ride in full sentence English first before creating their flowchart. They find looping and decision points ticky so modeling an example is essential.

example 1.


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There are lots of problems like these around. Key is not solving them but getting pupils to think about HOW they solved them. A simple problem can go along way. Ask pupils, perhaps in pairs to explain how they solved to another pair or to class. Aim to get them to write down how to solve as a series of steps.

knights tour

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This resource is courtesy of Prof. Paul Curzon, Queen Mary University. , specifically

Pupils need a counter, something to act like a knight. The rules are on the sheet though this is the simplest way to approach this activity…again pairing pupils work well. One of the key points of this is how representing a problem visually it can become simpler to understand and thus solve.

  1. hand out sheets and counters, explain tasks. Allow plenty of time to solve. Pupils who finish earlier can be activity gurus and assist others.
  2. next, on a blank piece of paper, pupils should draw a graph (computing graph!) of ALL possible moves from each and every square. They draw each square on the board as a circle then draw a line to another number circle that can be moved to.
  3. At this point, the graph may look messy, so ask them to redraw as clear as they can
  4. pose the question, Is there more than one solution, more than one route. Their hand-drawn graph should enable them to answer this.

robot ice cream server…

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Japanese ice cream vending robot. Pupils should first watch the video (the teacher could show many times to the whole class) . Pupils should then describe the actions of the robot as a series of numbered sentences. Don’t rush these steps as pupils are decomposing. Again pairing pupils work well. The final step is to create a flowchart. This should describe the actions seen in the video as a series of steps with decision points, where a loop is formed until conditions are met to move in to the next step.

example (without a decision) of flowchart for robot ice cream server
Japanese ice cream server