Tonicity is the measure of the osmotic pressure that flows through a semipermeable membrane. These are the reason why liquids must be placed in a container or vessel to contain them. Beakers, Flasks, and graduated cylinders can contain the liquid. They are like glasses except they are shaped to achieve a specific measurement. The contents of the tubing slowly migrated into the beaker due to low pressure that the beaker has compared to the tube.
