Hypothesis

Teaching science to children is just like teaching any other academic discipline (history, language, math, etc). If you get into the gritty details too soon, you'll scare them away. For a seven-year-old, a hypothesis goes into an experiment and comes out either valid or not valid. Either way, you've learned something. The fact that there may be an unlimited number of confounding factors can wait until at least middle school. This comic is from Zach Weinersmith at Saturday Morning Breakfast Cereal.