Formative Assessment
## Do students understand that volume is the amount of 3-dimensional space sand (or gravel or water) takes up inside a vial?

Observe students’ estimation strategies to find evidence that they understand volume is a 3–dimensional measurement.

Keep these questions in mind as you interpret students' estimation strategies:

- If students measure the height of the sample, do they use this dimension to figure out the 3–dimensional volume?
- If they measure the area (footprint) of the sample, do they recognize there is another dimension?
- Do they find a way to replicate the volume of sample using cubes instead of gravel?

Students often confuse volume in 3 dimensions with height, area or perimeter. In the following video, identify the strategy and decide if it is viable or not.

As a next step, ask students to show and explain the strategy they used.