1) When you are served a meal aboard an aircraft, the aircraft will encounter turbulence.

Related:

• Gunter's Airborne Discoveries: (1) When you are served a meal aboard an aircraft,
  the aircraft will encounter turbulence. (2) The strength...
• When you are served a meal aboard an aircraft, the aircraft will encounter turbulence.
  Gunter's First Law of Air...
• The strength of the turbulence is directly proportional to the temperature of you coffee.
  Gunter's Second Law of Air...
• Serving coffee on aircraft causes
  turbulence...
• Roger's Law: As soon as the stewardess serves the coffee,
  the airliner encounters turbulence. Davis's Explanation...
• As soon as the stewardess serves the coffee, the airliner encounters turbulence.
  Rogers' Law Serving coffee on aircraft causes turbulence...
• You will be winged by an anti-aircraft
  battery...