Sunday, 14 June 2015

Introducing Selection with Guess Who

I have discussed how the board game guess who can be used to introduce the concepts of variables in a previous post, but it occurred to me recently that the whole structure of the game is underpinned by selection statements. Therefore it seemed like a perfect way to introduce the concept to children.

Every time a child asks a question in guess who, they are creating a selection statement to follow. They know that if the answer is yes they have to knock down the characters lacking in the characteristic, but if the answer is no they knock down those with the characteristic. By getting children to play guess who, of which there are many cheaper titles with amusing variations on the name available, we can introduce them to the concept of selection using a context they are already familiar with.

To start this session, introduce the children to the idea of creating then, if else statements by asking how the player should respond to certain questions. I have used the scratch selection block to structure this, as the activity was original designed as an unplugged activity for a unit that developed the concept of selection using scratch (I suggest that children mimic the programming vocabulary and syntax they will be using in the unit). After this was introduced, children then played Guess Who and recorded each question they asked and the subsequent actions as if, then else statements. Understanding can be assessed further by asking children to deduce the questions that had been asked from given then and else statements, and by sequencing the questions of others.

After this the children were using scratch to create their own topic based quizzes using the ask and answer functions. However, after sharing the unplugged idea on twitter, Tim Head (@MrHeadComputing) suggested that someone should program a version of guess who. So, in the limited time I had available, I created a simple scratch program that uses events to create questions based on previous answers. Rather than playing the game against an opponent, you pick a character and the computer works out who your character is. I haven't used it with students yet, but can imagine that it would allow children to engage in purposeful computational thinking.  The Scratch file can be found here.
Ben Davies - @b3n3davies


  1. Brilliant! I'll adapt that one to my classes. Thank you for the idea.

    PS. can you correct a misspelling in your game? it's "wear a hat", not "where a hat".

    1. Thanks. I have updated the scratch file with the correct homophone and adding a new screen shot. Thanks for pointing that out. Much appreciated. Ben