Lesson 4 – Capacity
Objective
At the end of this lesson, student should be able to:
- Convert between units of capacity
Volume vs Capacity
If there are two terms that are most often interchanged in use and meaning, it is no other than volume and capacity. To give you an idea of the real differences between these two terms, let us make a comparison of their definitions.
Volume refers to the amount of three-dimensional space that it occupies. Some of the most common units of volume include cubic meters, liters, millilitres and cubic centimeters.
Capacity refers to the ability of something to hold. It is similar in concept to volume, but there are a few differences. One good example to illustrate the difference between capacity and volume, is how they are used in sentences. Take a look at the following:
The jug has a capacity of 250ml
The volume of milk needed to fill the jug is 250ml
The volume of milk in the jug is 175ml
The metric unit most commonly used for capacity is litre (l), the milliliter (ml), the kiloliter (kl) and the megalitre (ML)
Example 1
Convert
a) 300L to KL c) 500mL to litre e) 40,500L to KL
b) 55cm3 to mL d) 540mL to kL
Solution
a) 300L = 300 ÷ 1000 kL
=0.3kL 
b) 55cm3 = (55 × 1)mL
= 55mL cm3 = mL
c) 500mL = (500 ÷1000)L
= 0.5L 
d) 540mL = (540 ÷106)kL
= 5.4 × 10-4KL 
e) 40,500l = (40500 ÷ 1000)
=40.5kL 