How Plasma Cutters Work

By: Robert Valdes

States of Matter

A plasma cutter can pass through metals with little or no resistance thanks to the unique properties of plasma. So what is plasma?

There are four states of matter in the world. Most things we deal with in our daily lives are in the form of solids, liquids, or gases. These states are divided based on the way that molecules behave within each one. Take water as an example:


  • As a solid, water takes the form of ice. Ice is made up of neutrally charged atoms arranged in a hexagonal pattern that forms a solid. Because the molecules stay fairly still relative to each other, they form a solid -- something that holds its shape.
  • As a liquid, water takes its drinkable form. The molecules are still bound to each other, but they move relative to each other at slow speeds. The liquid has a fixed volume, but no constant shape. It changes shape to fit whatever container you put it in.
  • As a gas, water takes the form of steam. In steam, molecules move around at high speeds, independently of each other. Because the molecules are not bound to each other, a gas has no fixed shape or fixed volume.

Click on Cold, Warm and Hot to watch the H2O in this glass of water

move through three states of matter.

The amount of heat (which translates to the amount of energy) applied to water molecules determines their behavior and therefore their state. Simply put, more heat (more energy) excites molecules to the point that they break free of bonds that bind them together. With minimal heat, the molecules are tightly bound, and you get a solid. With more heat, the molecules escape the rigid bonds, and you get a liquid. With even more heat, the molecules escape the loose bonds, and you get a gas.

So what happens if you were to heat gas even more? This brings us to the fourth state: plasma.