Grade 6 → Mensuration → Volume ↓
Volume of Cubes and Cuboids
In the world of mathematics, it is very important to understand the concept of volume, especially when dealing with three-dimensional shapes such as cubes and cuboids. This detailed explanation aims to help Class 6 students understand how to calculate the volume of these solids.
Introduction to volume
Volume is a measure of the amount of space occupied by a three-dimensional object. When we think of filling a vessel with water, the space occupied by the water is its volume. In geometry, we often find the volume of solid figures.
Volume is usually measured in cubic units because it represents three-dimensional space. Common units include cubic centimeters (cm 3), cubic meters (m 3), and cubic inches (in 3).
What is a cube?
A cube is a special type of cuboid, where all sides are equal. Imagine a box where the length, width, and height are all the same. That's a cube!
The formula for finding the volume of a cube is:
Volume = side × side × side = side 3
For example, if each side of a cube measures 3 cm, then the volume of the cube is:
Volume = 3 cm × 3 cm × 3 cm = 27 cm 3
Here's a visual example of a cube:
Understanding cube with an example:
Imagine a dice used in a board game. Each side of a standard dice is 2 cm. To find the volume:
Volume = 2 cm × 2 cm × 2 cm = 8 cm 3
The volume of this cube is 8 cubic centimeters. Whenever you know the side of a cube, you can easily find its volume.
What is a cuboid?
A cuboid is a three-dimensional figure that has different length, width, and height. It looks like a box, and unlike a cube, its sides can be of different lengths.
The formula to find the volume of a cuboid is:
Volume = length × width × height
Visual example of a cuboid:
Understanding cuboid with an example:
Imagine a rectangular box with a length of 5 cm, a width of 3 cm, and a height of 8 cm. To find the volume of this cuboid, you multiply these three dimensions:
Volume = 5 cm × 3 cm × 8 cm = 120 cm 3
From this calculation we know that the cuboid occupies 120 cubic centimeters of space.
Why is calculating volume important?
Volume is an essential measurement in everyday life. It helps us understand how much space an object occupies. For example, when filling a swimming pool, knowing its volume ensures we know how much water we need. Similarly, when packing a box, knowing the volume of the box helps us estimate how many things it can hold.
Let's practice more!
Example 1: A small storage box
You have a small storage box with the following measurements: length = 6 cm, width = 4 cm, and height = 3 cm. What is its volume?
Volume = 6 cm × 4 cm × 3 cm = 72 cm 3
Therefore, the volume of the storage box is 72 cubic centimeters.
Example 2: A wooden block
Consider a wooden block that is shaped like a perfect cube. If the side of the block is 7 cm, what is its volume?
Volume = 7 cm × 7 cm × 7 cm = 343 cm 3
The volume of the wooden block is 343 cubic centimeters.
Example 3: A swimming pool
Suppose the backyard swimming pool is cuboid-shaped with dimensions: length = 8 m, width = 4 m, and depth = 2 m (consider the depth as the height). Calculate the volume of the pool.
Volume = 8 m × 4 m × 2 m = 64 m 3
The volume of the swimming pool is 64 cubic metres.
Units of volume
When working with volume, it is important to pay attention to the units. For example, if the dimensions are given in meters, the volume will be in cubic meters. Always remember the conversion factors:
- 1 cubic meter (m 3) = 1,000,000 cubic centimeters (cm 3)
- 1 cubic meter (m 3) = 1,000,000,000 cubic millimeters (mm 3)
- 1 cubic centimeter (cm 3) = 1,000 cubic millimeters (mm 3)
Understanding these units will help navigate between different measurement systems, especially in science and engineering.
Summary
Let's recall what we have learned so far about the volumes of cubes and cuboids:
- The volume of a cube is found by cubing the side length:
side × side × side = side 3
. - The volume of a cuboid is found by multiplying its length, width, and height:
length × width × height
. - Volume measures the space occupied by a shape and is expressed in cubic units.
- Understanding volume is practical for everyday tasks, such as packing, manufacturing, and filling containers.
Once you practice calculating volume several times, you will become more comfortable with the concept, and it will become second nature to you. Keep practicing with different examples, and you will continue to improve your understanding of volume!