Steam pressure is a very important property of steam when learning about steam turbine generators and gas laws.
Water in a gaseous state (steam) consist of water molecules that are more spread out and moving much more rapidly than the molecules of liquid water or ice.
The pressure of steam in a container is measured by how often and how many times these molecules of steam collide with the outside of the container. A single steam molecule will not exert very much force on a container, but the sum of the force of each molecule can exert a strong and measurable force.
When water is heated and steam is located and stored in the proper container, the force of steam pressure can become very powerful. This pressure can be used to create the rotational force needed to turn a turbine generator.
The force of steam pressure is shot through a nozzle in a steam impulse turbine and is strong enough to turn the blades of the turbine at such a high pressure. The same is true for a steam reaction turbine except the high pressure steam passes through a fixed set of blades instead of a nozzle.
Steam pressure is a fundamental aspect of many technologies today, and is used when generating a majority of the world’s electrical energy today.