Why did we spend three days studing mass and volume.

The relationship between mass and volume have with matter is that mass and volume define what is matter. For example, if the object has mass and volume than the object is a matter. Some things like air have indefinite volume and can be compressed to a certain limit. These objects are still matter because they have a volume and mass. Examples of objects that are not matter are light, shadow, dream and ideas. That is why I conclude that I think we learned mass and volume for three days is because it is the key points that identify matter.