Now you see it, now you don't. Our moon seems to pull a disappearing act from time to time—but why? Take your seventh grade scientists above and beyond to discover the truth about the moon and the role it plays in Earth's little...

Students try to guess the mystery subject Carlotta Facts, the History Mystery Museum's professor, is studying. They read the clues, do some online and offline research, and then attempt to identify the game's mystery item, Poor Richard's...