Question

How is a Eureka can used to determine the volume of an irregular solid?

Answer 1

A Eureka can is a beaker with a spout near its mouth. It can be filled with any liquid upto the spout as any excess liquid flows out of the spout.
The can is filled as high as possible with water and the object whose volume is to be determined, is tied with a thread and slowly inserted into it.
As the object fits into the can, the water it displaces pours out of the spout. This displaced water can be collected in a measuring cylinder and be measured - it will be the same as the volume of the object. For example a 10 cm³ cube will displace 10cm³ of water.