A sidebar examines a handful of less pressing scientific puzzles, such as why dogs bark.

There were two ways of solving a scientific puzzle, they said.

Again his eyes drifted off, as they had once or twice already; as if this were a scientific puzzle, to be analyzed and solved.

I asked you here to set you a scientific puzzle.

It is often the same way with scientific puzzles.

These claims have been a bit of a scientific puzzle, because they strike most people as utterly wacky and yet they are relatively widespread.

The older man's deep voice sounded composed and thoughtful, as if this scientific puzzle was the only thing he had to worry about right now.

Riddles in your teacup: fun with everyday scientific puzzles.

When the Beagle set out in 1831, the formation of coral atolls was a scientific puzzle.

Both the April and June panels said that too many pieces of the scientific puzzle were missing.