Metric Measurement Week

This week is National Metric Week in America where despite the fact that they still use Imperial measures such as feet and inches, there are some people who think that metric measures are the way to go. One thing led to another and the next thing we were discussing the developmental sequence that leads to deep understanding of linear measurement. As we were talking about that we decided to blog about our Linear Measurement Series, Books1, 2 and 3 which we researched, trialled in classrooms and produced in response to the poor attempts at the standardised test question that required students to mark the bubble that said how long the given line was. Right next to the line and correctly aligned was a broken ruler. Most students shaded the 9 cm bubble but the correct answer was 5 cm. That is almost twice the length. How come students: 

• could not measure with a broken ruler and 
• (perhaps more importantly) didn’t have any kind of visual spatial alarm bells going off in their heads telling them that no way was the line 9 cm.

From the research that we looked at it became clear that teachers needed more guidance about how to teach linear measurement than their basic training provided. The Linear Measurement books ensure that students have worthwhile experiences (no one in real life measures lines on a page for a living) and that those experiences should include: iteration, transitivity, conservation and estimation skills.

A developmental sequence

Each of the books has a Top 5 that explains exactly what aspect of linear measurement is being developed. The activities in the books are focussed on the Top 5 and, as an example, here is Activity 8 which focuses on the estimation concepts that are part of the above Top 5.

Using technology to teach measurement

The Three Snakes measurement app also grew out of this research. The app focuses on looking at the starting point and the finishing point when making comparisons. Often students only look at the end point as with the standardised test mentioned earlier. The Three Snakes app also provides opportunities for students to apply reasoning skills to comparison problems focussing on the comparative language of measurement, short, shorter, shortest, long, longer, longest.