Every once in a while I stumble across Piaget’s 7 Conservation Tasks and then I move on. This week was different because my thoughts around conservation won’t go away.

In a recent meeting with kindergarten and 1st grade teachers we discussed the importance of students being able to decompose and unitize number. This meeting has left me thinking that conservation is an conceptual underpinning of both skills. But I could be wrong.

In an effort to explore conservation we shared some videos in K-1 classrooms around our district.

We started here…



We paused the video at what do you notice and we shared our thoughts as a class.

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Gotta love what Kindergarten students notice.


Right before the flattened clay was placed back on the scale we hit pause again…

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Students predicted if the clay would weigh more, less, or the same using a slip of paper and unifix cubes (below).  With this being a kindergarten class we spent time talking about letter sounds at the beginning of each word and what each word meant.

Some students struggled with the letters/sounds but the majority of students were able to identify where more, less, and the same were located.  This turned out to be a quick and efficient way to formatively assess in multiple areas.

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We gave students an opportunity to share and explain their predictions.  Sharing predictions was the easy part. Explaining and justifying our predictions, not so much.

So we played some more and followed up with this…


And this…


And finally this one…


The whole idea of unitizing is a foundational understanding that students should own by the time they leave the primary grades. It’s our hope that by introducing the concept of conservation as it relates to length, weight, and liquid, that students are able to make connections across different contexts.

We hope that these contextual connections begin to help students explore how 1 ten is the same as 10 ones.


But it’s the fourth week of school and we know we have our work cut out for us.