How does an Aerosol spray work?

               Aerosols were patented in the United States of America in 1914 and have been increasingly used since the early 1950s. Aerosol cans and bottles are used to spray paints, perfumes, deodorants, furniture polish, oven cleaner, pesticides and many other liquid products.

       Initially the can is filled with the product to be sprayed and the propellant. When the push button is pressed, the product is forced up the dip tube and comes out as spray from the hole in the top. The top hole is very narrow and causes the liquid to break up into a fine, mist-like spray. Inside the can, the propellant is a gas under pressure usually a chlorofluorocarbon which forces the liquid in the tube to the top. However, concern about the damaging effects that chloro-fluro carbons have on the earth’s ozone layer has forced scientists to look for alternatives. The top of the can contains a valve with a spring that closes the value when the top is released.

Because an aerosol can contain a gas under pressure, it is dangerous to heat the can as it may explode.