Lesson

# Clip 12/13: Calculating Volume of Rectangular Prisms Lesson Part 2E

## Overview

Mallory gathers her students back to their own seats, sharing a “final thought as we’re going through this—volume is not just a formula ... Something that’s important and to understand is that you’re actually finding also the layers of something that can fill out that space.” She comments that in act two, she asked students to think about layers or slices, to figure out what’s hidden behind it. She says, “It all depends on what you see and what you don’t see,” and asks student to discuss “another way you could have found the volume of this instead of doing length times width times height.” She closes the lesson by appreciating the students for their good focus and engagement and asks students to clean up supplies and put them away.

## Teacher Commentary

A lot of the students decided to do the repeated addition and go layer by layer when drawing a model. One group attempted to do the actual three-dimensional model, so I really thought that was a great challenge for them. That was great spatial reasoning; however, they would need more time, and I think giving them more time to continue to try to attempt that would've been great. But I think the really hard part today wasn't necessarily that there was a major misconception that I need to reteach. It was more: how can I start off with the reasoning that volume appears in several different ways, like layers, or a base times a height, and having them draw that out so they can reason through it? Maybe this is the stuff I don't see, and this is what was given to me versus just plugging in a formula, length times width times height, and then getting it done. I think when you follow a formula, you're not able to actually understand what's happening within the space that's provided.