Saturday, November 2, 2013

Are the Zeros T00 Visual?

My wonderful 8th graders were recently studying scientific notation, and I noticed a few of them with the same misconception.  They looked confident in their knowledge (from past years' lessons) of how to do the usual "count" and put the decimal, then add "multiply by 10 with an exponent".  But, they were counting the zeros, not the places.  This does work in a few cases, but not always.  So I wondered why they were doing this....(I like to wonder about many things).

Looking at many lesson plans and activities that teachers use to teach scientific notation, there are always numbers with lots of zeros.  Visually, the zeros are very prominent in the numbers, whether they are very large or very small numbers.  Is this emphasis why my students were counting only the zeros?


Also, of course, the students had forgotten or did not realize that there should be a one-digit whole number (and only one, not two or three).  So, we had discussions about why exactly we should count the places and not just the zeros.  Plus some analysis of if you actually think about how the 10 to the exponent will result in the standard notation.

Just a thought, but the "visualness" of the zeros might trip some kids be on the lookout for students counting zeros.