Equal volumes may have different weights for many reasons, for instance:
1. The densities of the substances may be inherently different. This happens with non food items too, for instance a cubic metre of aluminium weighs less than a cubic metre of iron.
2. Powders can pack differently, so one may have more air spaces.
3. One substance may be damp.
No, the 10g piece of aluminum and 10g piece of iron would not have the same volume. Different materials have different densities, so even if they have the same mass, their volumes will be different.
WATER
Because many of them are powders. The same weight of a powder can have many different volumes, depending on how much air has been fluffed into it. For example: When you sift flour, you get more volume out of the sifter than you put into it, although the sifter obviously doesn't change the weight of the flour.
Capacity is referring to volume, not weight. Weight is the force of gravity acting on an object. 1 pound of lead and one pound of wood have the same weight (1 lb) but they have very different volumes (capacities).
different equal
You need to specify what the liquid is that you are measuring. The liter is a measure of volume, and the stone is a measure of weight. Liquids with different measures of specific gravity (similar to measures of mass for solids) will fill different volumes at the same weight.
Yes, you can.
no as there is different volumes of water
No, not unless they are made of the same substance. Different substances have different densities, which means that the same volumes will have different masses.
If two solids have the same masses but different volumes they have different densities.
it depends on the density of what you are comparing. Pints is a measure of volume while grams is a measure of weight, so it is impossible to answer since the same volumes of different things weigh different.
Different metals have different volumes for the same mass.