Why do leaves change color in the fall?

Question: Why do leaves change color in the fall?
- Keywords:
  autumn,
  leaf,
  plant,
  season
Asked by danniella1588 to Colm, Eoin, Joseph, Lauren, Stephen on 15 Nov 2013.
- Joseph Roche answered on 15 Nov 2013:
  
  A chemical called chlorophyll in leaves is green. It needs sunlight to turn water and carbon dioxide into oxygen and sugar. In the autumn/winter there is less sunlight so the trees reduce the amount of chlorophyll in the leaves so they become less green.

Question: Why do leaves change color in the fall?