Audrey has provided some good examples! Another case, albeit less sophisticated, that comes to mind is trying to determine how long it takes to wake up without an alarm clock. Suppose I hypothesize that I wake up an hour later than if I had decided to set my alarm. Then I would actually test it out for many days (trials), and either reject or support my hypothesis with my findings after having recorded them.
No matter what example you end up choosing, it should exemplify how we as humans are constantly observing, asking questions, experimenting, and trying to explain certain phenomena, however big or small. Keep that in mind and I'm sure the ideas will come flooding in!
Hope this helped,
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