How can centimeter cubes help us measure volume?
Plan Investigating Volume 2
In the last session, students had a fairly easy time putting objects in volume order because the objects were dissimilar in size. In this session, the exercise becomes more difficult.
Formative Assessment
Can students use centimeter cubes to measure the volumes of 4 blocks?
Available online at inquiryproject.terc.edu
Challenged to order four wood blocks of different shape but similar volume, students struggle to “guesstimate.” As it becomes clear that they need a standard unit of measure, students are given centimeter cubes to work with. By constructing replicas of the blocks with the cubes, they are able to check their estimates and put the blocks in proper volume order.
By the end of the investigation, students will have a firsthand appreciation of the need for a standard measure of volume, as well as a hands-on understanding of the unit “cubic centimeter.”
Learning Goals
- to appreciate the need for a standard measure for volume
- to describe volume in cubic centimeters
| Sequence of experiences | ||
|---|---|---|
| 1. Think about measuring volume | All Class | 10 Mins |
| 2. Place four blocks in a volume line | Small Groups | 15 Mins |
| 3. Explore cubic centimeters | Small Groups | 5 Mins |
| 4. Measure the volume of the blocks | Small Groups | 15 Mins |
Materials and Preparation
For the class:- Post the investigation question in a place where all students can see it.
- Prepare and post a class table labeled “How We Measure Things”; an example is given in Step 1.
- Prepare and post a class table labeled “Order of Blocks by Volume”; an example is given in Step 2.
- The class volume line from the previous session (with the Styrofoam, maple block, cubes, et al.)
- Label sets of 4 wooden blocks A, B, C, D; see image in Step 1.
- 1 set of 4 wood blocks labeled A, B, C, and D, or enough blocks for each student to have 1 block
- At least 75 cubic centimeter blocks
Notebook Pages
Can students use centimeter cubes to measure the volumes of 4 blocks?
Look for evidence that they can distinguish volume from other measurements as students use centimeter cubes to find the volumes of 4 blocks. Third grade students often confuse volume with area or height.
Keep these questions in mind as you interpret students' strategies:
- Do students take all 3 dimensions into account as they estimate the order of the blocks by volume?
- When they check their estimates, do they line up the cubes along one edge? Surround the block? Measure the height? Build a 3–D copy or replica?
To provide more experience with a difficult concept — volume is hard — a next step might be to pair students and ask them to explain their measurement strategies to each other.
