dday392 wrote:My parents and i dissagree on this matter i think its imposible because you can have the same volume of a different material and it would not weigh the same but they say because onces are used in both volume and weight it is possible
You are right, weight to volume conversion is not possible in general since the same volume of various substances could weigh differently. On the other hand, for a particular substance you can convert from volume to weight. For example 1 liter of water weighs 1 kilogram.
In general to convert from volume to weight or vica versa you need to know the density or specific gravity of the substance being converted.