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# Secondary Magazine - Issue 57: An idea for the classroom

This page has been archived. The content was correct at the time of original publication, but is no longer updated.
Created on 30 March 2010 by ncetm_administrator
Updated on 13 April 2010 by ncetm_administrator

# An idea for the classroom - linear clock

You don’t really get a good perception of this resource from a screenshot, so you will need to go and get the ‘live’ version from the TSM Resources website. After you and your pupils have looked at this image for a few seconds, you may want to start asking some questions, or invite the pupils to ask some questions, to start thinking about.

I started with the question: "What is moving?"

My Year 7 pupils were happy to tell me that the top row, or seconds, was moving. They then quickly followed that by saying ‘the minutes’ and ‘the hours’ with the rapid realisation that everything (except the green line) is moving.

So how fast are they moving? It may be easier to ask how much faster one row is moving than another. For example, ‘how much faster are the seconds moving, than the minutes?’
This was easy. The seconds and the minutes are represented by equal sized blocks and there are sixty seconds in a minute, so it was obvious that the seconds were moving 60 times faster than the minutes.

‘How much faster are the minutes moving than the hours?’
So if the minutes and hours were represented by the same size blocks, the hours would move 60 times faster than the minutes. But the hours are represented by bigger blocks – what difference does that make? We needed to make a measurement at this point and decided that the block representing the hour was 2.4 times bigger than the block representing the minutes

To help structure our thinking we used the following diagram:

Pupils were then quick to suggest questions which allowed the comparison of different rows of the clock. Do tell us if this resource enabled some good proportional reasoning to take place in your classroom.

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