The key question pupils chose to follow was how high was the chair/ how high is the table. Pupils worked out their own answers in groups with no help. They put together a short answer on a post it and 'posted it' under their question. One group asked to do a different question so they put it on an A3 sheet - stuck it up and followed their own thread.
We then compared answers and more importantly methods. From this the pupils themselves discovered that we could estimate using the relative heights of people in the picture, we discussed average heights and off they went again, reviewing their work and improving their answers.
The starter activity ended up taking most of the lesson, we covered metric and imperial conversions, implications of imperial units and decimal calculations, estimating, rounding, averages and reveiwing and improving our work. All the information was drawn out of the pupils and driven by them.
There was a brilliant moment when someone put an answer on one of the questions we had discarded as needing research as she had an answer for it. This allowed us to talk about independent enquiry and was the first 'in' for getting the pupils to take over their own learning.
Feedback was extremely positive. We did get onto the dots. Pupils made their guesses, we had time to write down the 'long list' of answers and the homework set was "sort out the data for next lesson". This really frustrated them because I haven't told them how to do it. I was open about this - I told them I was deliberately not helping them but that they couldn't get it wrong - I want to see how they sort the data. That is our starting point for tomorrows lesson.