A Measuring Cylinders / graduated cylinder / cylinder measuring / mixing cylinder is a piece of laboratory apparatus used to measure the volume of a liquids, chemicals or solutions during the lab daily work. Graduated cylinders are more precise and accurate than the common laboratory flasks and beakers.

Liquids have a fixed volume but no fixed shape. Gases have no fixed volume and no fixed shape. Gases expand to fill the space available. They can also be compressed into a very small space.

Fixed volume is the property of liquid and solid. Unlike gases, where the volume changes without applying any external force.

Matter in the solid state has a fixed volume and shape. Matter in the liquid state has a fixed volume, but it has a variable shape that adapts to fit its container. Its particles are still close together but move freely.

Matter in the liquid state maintains a fixed volume, but has a variable shape that adapts to fit its container. Its particles are still close together but move freely. Matter in the gaseous state has both variable volume and shape, adapting both to fit its container.

Gases do not have a definite shape or volume because the molecules in gases are very loosely packed, they have large intermolecular spaces and hence they move around. The particles of solid are closely packed and occupy less space while particles of gases are loosely packed and occupy the complete space available.

Definite (for both shape and volume) means that the container makes no difference whatsoever. If 5-liters of liquid water is poured into a 10-liter container, the liquid would occupy 5-liters of the container and the other 5-liters would be empty.

A gas does not have a definite shape or volume. Gas molecules will spread out evenly to fill any container. You could use the following example to help students appreciate how far apart the molecules of a gas are compared to the molecules in a liquid or solid: Imagine what a tablespoon of water looks like.