matter with variable volume and shape expands to fill the shape and size of its entire container
fluids has shape_of_containers solids has not definite_shape_and_volume container is container_shaped_object. solids has definite_shape_and_volume container_shaped_object is cavity_or_container. matter has mass container_independent_shape is finite_spatial_thing. container is not container_shaped_object. container_independent_shape is not finite_spatial_thing. volume is size.