A man drops a glass on the floor, but somehow it does not break. Why?
The wording makes most people automatically picture a fragile drinking glass made from actual glass. But the word “glass” can also be used casually for a drinking cup, and not every drinking cup is breakable.
If the man drops a lightweight plastic cup or plastic drinking glass, it may simply bounce or land without breaking.
That is what makes this riddle work. Your mind fills in a detail that was never actually provided: that the glass must be made of glass.
Many riddles depend on exactly this type of assumption. The question sounds impossible until you stop adding information that is not there.
Answer: It was made of plastic.
