Aerosol cans come in a variety of sizes and shapes and serve as containers for a variety of substances, but they all work in the same way: by exposing a high pressure fluid, another fluid is squeezed out of the nozzle.

If you apply enough energy to the fluid (by heating), the particles in the liquid will vibrate violently to break the forces that bind them together. In this way, the liquid becomes a gas and becomes a fluid that makes up the particles to move independently. This is the boiling process, and the temperature at the time of boiling is called the boiling point of this substance. Different substances have different boiling points: for example, the amount of heat required to change water from a liquid to a gaseous state is more than the amount of heat required to change the alcohol from a liquid to a gaseous state.

The forces generated by the individual moving particles in the gas are superimposed and can create considerable pressure. Because the particles in the gas are not bound together, the gas does not have a fixed volume like a liquid: the particles are constantly pushed outward. In this way, the gas will expand and fill all open spaces.

When the gas expands, its pressure becomes small, and the number of particles colliding with each other in any given region is reduced, so the pressure is simultaneously reduced. When the gas is compressed into a relatively small space, a large amount of pressure can be generated because there are more moving particles in a certain area. Aerosol cans use these principles for a simple purpose: to push a liquid substance out.

The aerosol canister contains a fluid having a boiling point below room temperature (referred to as a propellant) and a fluid that is boiling at very high temperatures (referred to as a product dose). The product dose is the substance we actually use - such as hair spray or insect repellent. The use of a propellant is a method of pushing a product agent out of a can. Both fluids are stored in sealed metal cans.

The liquid product is first filled, after which the aerosol canister is sealed and the gaseous propellant is pumped through the valve system. The gas is pumped under high pressure. Therefore, it squeezes the liquid product agent with a large force. In this aerosol canister, a long plastic conduit extends from the bottom of the can to the valve system at the top of the can. It has a small nozzle that can be   pressed, with a narrow pipe in the middle. This pipe extends from the inlet near the bottom of the nozzle to a small nozzle at the top. The spring pushes the nozzle up, so the pipe inlet is firmly blocked by the sealing device.

When you press the nozzle, the inlet moves under the seal, which opens the passage from the tank to the outside of the tank. The high pressure push gas drives the liquid product charge up the plastic conduit and ejects the nozzle. A narrow nozzle atomizes the flowing liquid - breaking the liquid into tiny droplets to form a fine spray. The plastic nozzle on the aerosol can pushes a small valve to allow the compressed product to flow out of the can.