# Finding Volume Measurement: Understanding the Unit Cube Concept

Students will investigate the concept of volume measurement using a unit cube.

Identify a “unit cube” as a cube with side lengths of one unit and with a volume of one cubic unit. Scroll to the end of this article to download a copy of this lesson plan.

**Lesson Objective:** The lesson is aligned to the Common Core State Standards for Mathematics – 5MD.3a and b Geometric Measurement – Recognize volume as an attribute of solid figures and understand concepts of volume measurement.

**Materials Required: **“unit cubes”

## Identifying Measurement of Rectangular Figures Using a Unit Cube

Look at the unit cube in the image above. Each side of the cube measures 1 unit. A cube with each side measuring 1 unit is called a unit cube. A unit cube has a volume of one cubic unit.

A unit cube can be used to measure volume.

To measure the volume of a rectangular figure, without gaps or overlaps pack the rectangular figure with the unit cubes.

Look at the rectangular figure in the second image above. The rectangular figure is packed with 6 unit cubes. The volume of the rectangular figure is 6 cubic units.

Look at the rectangular figures above. Count the number of unit cubes packed in the rectangular figure.

- How many unit cubes are packed in the rectangular figure shown in Figure 1? What is the volume in cubic units?
- How many unit cubes are packed in the rectangular figure shown in Figure 2? What is the volume in cubic units?

**Answers:**

- 12 unit cubes, 12 cubic units
- 18 unit cubes, 18 cubic units

## Individual or Group Work

Look at the figures above. Count the number of unit cubes packed in the figure.

- How many unit cubes are packed in Figure 3? What is the volume in cubic units?
- How many unit cubes are packed in Figure 4? What is the volume in cubic units?
- How many unit cubes are packed in Figure 5? What is the volume in cubic units?

**Answers:**

- 15 unit cubes, 15 cubic units
- 14 unit cubes, 14 cubic units
- 8 unit cubes, 8 cubic units

Students should be able to count the number of unit cubes used to fill rectangular figures to determine the volume of the figures.