How Does a Spray Can Work?

Can't Stand the Pressure

Inside a spray can is a liquid, usually a paint, deodorant, insect repellent or another liquid. This liquid is pressurized with an aerosol gas. It does not bind or become absorbed in the liquid.

Releasing a Little Steam

Since the can is under pressure, the contents will escape when there is an opening. In the case of a spray can, there is a nozzle that opens when depressed. The liquid and gas inside the can then escape through this small hole.

Destination Evaporation

Once the valve is opened, some of the gas inside the can will immediately evaporate. It then carries the liquid with it as it escapes through the nozzle. Since the aerosol evaporates quickly once it hits the air, only the liquid is propelled in small particles. This allows the spray can to distribute the liquid evenly and in a fine mist.

Smaller Particles Means a More Even Application

When the liquid is released with an aerosol, it disburses into finer, smaller particles because of the pressure on the liquid and the small size of the nozzle. As the gas expands and evaporates, it can also carry these fine particles farther away from each other. This is how a can of spray paint gives you a more even application and a fine mist-like spray.

Resources

• History of aerosol
• More information on aerosol cans