Alternatively, you can space the seeds 6 to 10 inches (15.24 to 25.4 cm) apart and thin your seedlings out once they reach 4 inches (10 cm) tall. At that point, you should consider thinning them out so that they are 18 inches (45.72 cm) apart.
Volume - Arcy Art Original Oil Paintings Art Dictionary. Volume is the size, bulk and dimension of a particluar object. It is an object that is usually thick, nontransparent and exists solidly and three-dimensionally in space and it is not flat. In a painting a volume is represented with light and shade and usually in spatial situation to make the nonflatness clear.
In art, a medium is the material that artists use to create their art. It's that simple. Whatever a piece of art is made out of is its medium. The plural of medium is media. So, one piece of art can be made of one medium or several media. If you've ever been to an art museum or gallery, you've probably seen those little signs next to each piece that look something like this: