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 Authentic assessment on understanding scale

As a preliminary task ask the students to try and describe the size of something smaller or bigger than that can accurately measure, think atom, planet…

         To get a sense of what they know, how well they can express themselves-

After the lesson, go through the part of the conversation we had, “describe how big a water molecule is”, without any rigid guidelines

         To see what got through in this first turn through the topic, and to describe what their thinking is-

In a subsequent lesson, have them test their understanding of scale in a different context, but on a similar order of magnitude (us to a water molecule), one with specific measureable results.

         Transference of ‘owned’ knowledge-