 The question centers on objects, organisms, and events in the natural world.  The question connects to scientific concepts rather than to opinions, feelings, or beliefs.  The question can be investigated using available technology and resources.  The question leads to gathering evidence and using data to explain how the natural world works.

 “Who is a better performer, Lady Gaga or Madonna?” is not testable because it centers on opinion.  “Are fairies real?” is not testable because it involves the supernatural.  “Is there life on other planets?” is not testable because we currently lack the technology to investigate other planets.

 “Which has more sugar, Coke or Pepsi?”  “Do phosphates in the water encourage algae growth?  “Does running the air conditioner or driving with windows down use more gas?”

 Which is a smarter dog breed, Labradors or Poodles?  Who can hold a note longer, Madonna or Lady Gaga?  Which brand of paper towel is better, Bounty or Brawny?  Will using fertilizer make plants grow faster?

 Sometimes questions can be made testable with a little work.  For example, How can we make one of our un- testable questions testable? “Which brand of paper towels is better: Bounty or Brawny?”

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