Reasonable Answers

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This week my third grade class started to learn about measurement.  Measurement is one of those topics that doesn’t see much light of day.  Number lines and computation are very prevalent in elementary classrooms, not so much with measurement.  This is especially the case when it comes to metric measurement.  Every grade level teaches a form of measurement, but conversions aren’t discussed on a regular basis.

As I was looking for ways to review I came across a gram measurement set in my school’s storage room.  I was looking for a digital scale but couldn’t fine one.  I dusted off the tiny weights and also found a balance.

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Winner!  So I brought them back to class.  The next day my third grade class had a discussion about how to calibrate a balance and use small weights to find measurements.

While reviewing I started to find that students struggled with the reasonableness of their answers.  They had trouble identifying what a gram, 100, or even 100 grams really looked like.  They had an easier time with conversions, but that is more of a process and not an understanding.  So I brought the class to the back table and found an empty container.

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It measured exactly 510 grams.  It was empty so students knew that it couldn’t be that exact amount Students took turns and added the weights to see if they could balance the equation items.

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Not balanced

Students were excited to add/deduct the weights to find balance.  It seemed like a puzzle to them.  The balance was even at 41 grams.

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Even steven

It took a small amount of time before students calculated that the oats would weight approximately 510 – 41 = 469 grams.  This also led to a quality discussion about the weight of products vs. the container that it fits in.

This was decent activity to bring out a better understanding of what a gram really is.  Next week we’ll be exploring kilograms.

Author: Matt Coaty

I've taught elementary students for the past 14 years. I enjoy reading educational research and learning from my PLN. Words on this blog are my own.

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