We were right in the middle of a maths unit on shape and symmetry, when the learners started using everything they could get their hands on to see how long our learning space was.

Once again, I was witnessing that independent, task-fuelled collaboration.  But in addition, I was seeing where their interests lay, and I knew that we should grab on to this enthusiasm and move into looking at length.

Being 5/6 years old, my learners have mostly used non-standard measurement.  It was now time to introduce standard measurement.  I didn’t want to just make a switch.  I wanted them to start questioning the use of non-standard measurement, and to think about about why standard measurement was so important.

I set the context.  Over the school holiday, I plan to do some classroom alterations and to do that, I need to know how long the classroom is, and I need to share this information with others.  I’ve decided to measure the classroom in ‘Sarah’s.  I get Sarah to lie on the floor and we estimate – how many Sarahs do we think it will take?  Estimations are made, and so we begin!

Once we have determined how many Sarahs it takes, I say I will email this information to our school principal, but he quickly emails back and says he doesn’t understand as he doesn’t know how big a Sarah is.  I ask the children to stand up, and they all show me how big they think she is.

Looking around, they can see that they all have different ideas.  Why would that be a problem?  After some discussion, we realise there are no numbers on Sarah!  So what DOES have numbers on, and would it be helpful?  I bring out some rulers and we do a bit of investigation.

The children realise they are all the same.  The distance between each number is the same.  If you measure the same thing with different rulers, you get the same answer every time.  So would it be better to measure the room with Sarahs or rulers?  Rulers they yell jubilantly!  Now we can ensure our principal knows the size of our room.  Hurrah for standard measurement!