There are distinct units of measurement for object in day today life. The system of measurement varies for 2 dimensional and 3 dimensional objects. The two major ways in which 3-d objects can be measured is in terms of volume ad capacity. Even though the terms are interchangeably used in day today life, they are very different for each other.

**Volume vs Capacity**

The difference between volume and capacity is that volume is a characteristic of a substance and capacity is the holding capacity of an object.

Volume is basically the space taken up by a substance in any state, while capacity is the amount of substance a said container or medium can hold.

For example, there is a glass, with some water in it. The area occupied by the water, in this case, would be the volume, however, the amount of water required to completely fill the glass up to the brim will be its capacity.

## Comparison Table Between Volume and Capacity (in Tabular Form)

Parameter of Comparison | Volume | Capacity |
---|---|---|

Definition | The total amount of space covered by matter in any state, solid, liquid or gas. | The amount of substance a medium can hold in a said state. |

Meaning | It is basically the amount of the substance in question, with respect to space it takes up. | Potential holding capacity of an object. |

Measurement | Volume is usually measured in cubic meters or cubic centimeters. | Capacity is measured in litres and gallons |

Object | Any object, irrespective of state can have volume as long as it covers space. | Capacity is a characteristic feature of hollow or porous objects. |

Example | The amount of milk in a carton is the volume of the milk. | The maximum amount of milk that is required to fill up the cartoon is the capacity of the carton. |

## What is Volume?

Mathematically, the volume is the space occupied by it or the amount of space it encloses. The volume of a substance can be calculated for a given substance if it exists in a regular geometric shape, for example, cube, sphere etc. using assigned formulas.

The general formula for calculating the volume of an object is the multiplying the height, width and length with each other. For calculating the volume of certain irregular shapes, integral calculus can be used.

It obvious that one-dimensional and two-dimensional objects have zero volume. Volume is measured in cubic meters and cubic centimeters. The term cubic signifies the number of cubes of the given unit that can be placed within the enclosed space.

Another technique used to calculate the volume of a substance is called fluid displacement. The principle of fluid displacement states that the volume of fluid displaced by object, when immersed is equal to the space occupied by the object, hence this becomes the volume of the object. This technique is specifically useful for measuring the volume of a solid object especially is the shape is irregular.

The unit of volume can be derived from its corresponding unit of length. The SI or International Standard Unit for volume is cubic meter (c3).

## What is Capacity?

Capacity refers to the ability of a substance to hold matter. The general term capacity can be applied to various places indicating potential. Mathematically capacity is the maximum amount of substance, usually fluid that can be placed within the said object.

Capacity in mathematics is closely related to volume, however, there is a slight difference when it comes to calculating volume and capacity. When calculating the capacity of a container, only the hollow space is taken into account, hence it is that amount of fluid required to completely fill the object, however in case of volume the entire object including the container’s dimensions is taken into account.

The metric term used to express the capacity of a substance is litres, gallons etc. The conversion between litres and cubic meters is pretty simple.

Capacity is generally a characteristic feature for objects. It is the more frequently used term in day-to-day life. The amount of product inside a bottle of shampoo we buy is listed in litres because you will be charged according to the cost of the shampoo, hence the capacity of the container matters.

To understand this in a better way, consider a thermosteel bottle. Such bottles have multiple layers of thermostatic substance lined inside the walls of the container. Such bottles usually have a smaller capacity than what any person would estimate based on the overall volume of the bottle.

Hence capacity is the fluid holding potential of an object.

**Main Differences Between Volume and Capacity**

- Volume is defined as the measure of the space taken by mass while capacity is the fluid holding potential of an object.
- The amount of area taken up by a substance, at a given time is its volume, versus the amount of fluid required to fill up an object up to the brim, is its capacity.
- Mathematically, volume is measured in cubic meters whereas, Capacity is measured in litres.
- Volume can be calculated by using fluid displacement while capacity cannot be calculated by fluid displacement.
- Volume is a characteristic of the substance, while capacity is usually a characteristic assigned to hollow container like objects.

## Conclusion

Measurement of 3-dimensional objects can be done by estimating both volume and capacity. Although both terms are often used interchangeably, there is a slight difference between the two.

The volume of a substance is the area enclosed within its boundaries, whereas capacity is the maximum amount of fluid an object can hold.

The key difference that must be noted while calculating the two is that, in case of volume, the entire entity is taken into consideration, while measuring the capacity the dimensions of the container are excluded from the calculations.

## References

- https://journals.sagepub.com/doi/abs/10.3141/1581-06
- https://www.safetylit.org/citations/index.php?fuseaction=citations.viewdetails&citationIds[]=citjournalarticle_604385_38

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