Volume is the space occupied by a body.
The SI unit of volume is m3
A- Volume of regularly Shaped Objects
Volume of some of the regular solids can be calculated using the formulae given in the following table.
|Cube||(length)3 = L3|
|Cuboid||length X breadth X height = L x b x h|
|Cylinder||pi x radius2 x height = pi r2 h|
|Sphere||4/3 x pi x (radius)3 = 4/3 pi r3|
|Cone||1/3 x pi x (radius)2 x height = 1/3 pi r2 h|
The solid shape must be hard to be measured accurately; if it is made up of clay or something similar will the calculated volume will not be the true volume.
B- Volume of Irregularly Shaped Objects
Volume of irregularly shaped objects can be found out by
i- Displacement method.
By measuring the volume of displaced liquid by an object. We can find the volume of these solids with the help of a measuring cylinder.
a- Fill the overflow vessel with water until the water start overflowing.
b- When water stops overflowing, place the measuring cylinder below the overflowing tube.
c- Slowly lower the irregular solid into the water by a very thin string.
d- When the water stops overflowing, read the volume of the water collected in the measuring cylinder.
e- This reading will be the volume of the irregular solid shape.
i- Measuring cylinder.
To measure the volume of an irregular body using measuring cylinder
a- Pour water into a clean measuring cylinder (nearly three fourth of its volume) and record the level of water (v1).
b- Slowly lower the irregular solid into the water by a very thin string.
c- Measure the new volume of the water and the stone (v2).
d- Then calculate the volume of irregular solid shape as
The volume of this stone = ………….
you can use measuring cylinder for sure to measure the volume of liquids.
- The measuring cylinder must be placed on a horizontal bench.
- Using large measuring cylinder to measure small amounts, leads to errors in results.
- You have to avoid parallax error.
- If the string holding the stone is thick it may cause a reading error or absorb little amount of water.
- Equal masses of different densities have different volumes
- Reading must be taken at the lowest level of meniscus or curved surface of the liquid.
- Reading must be taken at the top level of meniscus or curved surface of the liquid in case of Mercury.
- Liquid A is water and liquid B is mercury.