z If you want to measure the volume of a liquid, use a graduated cylinder. When liquids are poured into a graduated cylinder, the surface of the liquid does not appear to be level. The centre point of the liquid appears to be lower than the edges touching the cylinder. This bowl shape is known as a meniscus.
Many meniscus meanings!
The word ‘meniscus’ is also used to describe a part of the knee joint in humans. Find out why.
z If you want to measure the volume of a small object with an irregular shape, place it in a graduated cylinder with a known volume of water. You can then record the new level of the water. The difference between the levels is the volume of the object.
z If you want to find the volume of an irregular shaped object that will not fit into a graduated cylinder (for example, a large stone), it can be placed in an overflow can filled with water. As the stone is lowered into the water, the water will spill out of the can and is collected by the graduated cylinder. The volume of water collected is the volume of the stone.
Overflow can 3030 30 30 cm3
15.3 65 cm3
30 cm3
Stone
The volume of the stone = 65 – 30 = 35 cm3
Fig. 15.3.5
Measuring the volume of an irregular object using a graduated cylinder
How to use a graduated cylinder
To get an accurate reading for the volume of a liquid from a graduated cylinder, you need to take the reading at eye level from the bottom of the meniscus, as shown in Fig. 15.3.7.
2020
20
1010
10
Fig. 15.3.7 The correct way to read from a graduated cylinder
