These little worlds are meticulously standardized: equal volumes of sterile bedding, steady cycles of light and dark, even a consistent flow of temperature - controlled air. (sciencemag.org)
If the bottles are filled with equal volume and pressure then both matter. (principia-scientific.org)
* 2 1/2 cups uncooked short grain rice * 2 1/2 cups water * For superior results use equal volumes of rice and water (healthygreenkitchen.com)