How does the gas on top of the liquid in an aerosol can cause the liquid to come out of the spray nozzle?

Question: How does the gas on top of the liquid in an aerosol can cause the liquid to come out of the spray nozzle?
- Keywords:
  aerosol,
  gas,
  liquid
Asked by niamhcarr to Amy, Karen, Sarah, Vijay, Will on 18 Jun 2012.
- Will Reynolds answered on 18 Jun 2012:
  
  Hi Niamh. An aerosol is a suspension of tiny liquid droplets in a gas. An aerosol can contains both a liquid and a gas that is pressurised. When you spray an aerosol the liquid and the gas are mixed by the nozzle and makes liquid droplets small enough to stay suspended in the gas when it is in the air.
- Sarah Martin answered on 20 Jun 2012:
  
  Hi niamhcarr,
  
  Here’s a full description with diagrams of how aerosol cans work!
  
  http://science.howstuffworks.com/innovation/everyday-innovations/aerosol-can3.htm
  
  All you’ll ever want to know about it, on quite a nifty website.
  
  🙂 Sarah

Question: How does the gas on top of the liquid in an aerosol can cause the liquid to come out of the spray nozzle?