Question

Why do they difter!
The mass of the copper and the iron blocks are the same because
their weights are the same. But are their volumes the same?​

Answer 1

Because of diffrence in density.

Density = weight /volume.

If you take same volume of two different materials, the density is higher the weight is higher for same volume.

Now, if i make weight constant, where

Weight = Density * volume

The volume will change since density wouldn't change as it is a constant at a given temperature.

Copper has higher density, 1 kg of copper is smaller in volume than 1kg og iron.