Volume of irregular solids
In order to measure the volume of irregular solids, we follow an indirect way of measurement. For this purpose, we use a graduated cylinder or an overflow can. Let us see, how?

a) Using graduated cylinder
For small solids, we half-fill the given graduated cylinder with water and note the reading. Now, dip the solid in it after tying it with a thread as shown in Fig. 1.17. You will notice that the water level rises in the cylinder. Note this reading also. Thus, the difference in the readings of the water level before and after insertion of the solid gives the volume of the solid.
We cannot use water if the given solid is a piece of water soluble material, such as rock salt. In such a case, we must use a liquid in which the given solid neither dissolves nor reacts chemically.

b) Using an overflow can
If the given solid is so large that it cannot be dipped in a graduated cylinder, then we use a large overflow can with a spout. We fill the overflow can with water can with a spout. We fill the overflow can with water till it starts overflowing as shown in Figure
We wait till no more drops overflow. We then place a clean graduated cylinder below the nozzle of the overflow can and dip the given solid in it. Some water overflows and collects in the graduated cylinder. The volume of water overflown is carefully noted. This is equal to the volume of the given solid.