Why do this problem?
is a way of practising reading scales in a challenging context. The challenge comes from the reasoning involved.
This activity could form part of a lesson on reading scales or one on capacity.
You could have the image of the cylinders on the board as an introduction, and begin by reading the clues together. (You may find this SMART notebook file
useful. It contains the images from the problem, and the text which can be revealed gradually. Thank you to Mark Dawes for allowing us to share this file.) Ask learners to think on their own
about which clue they could use first, then encourage them to talk to a partner. Invite suggestions from the whole group about where to start and why. Children could then work in pairs on the problem.
As the children work, listen to their discussions and in particular listen out for those who are justifying their choices clearly. Warn a few of these pairs that you would like to hear from them during the plenary, asking them to focus on their reasoning and explanations.
Which cylinder do you think holds 1000 ml?
Which would be another easy one to try?
Which clue could we use next?
Children could write their own questions using the blank sheet
Children could use the resource sheet
and write down the amount in each cylinder. Alternatively, this sheet
with the clues and space for noting the amount in each cylinder, might be useful. It might help to have labels of the children's names, for example on pieces of
paper or card, which can be moved around underneath each measuring cylinder.