Ballard did not know exactly where the Titanic’s wreck was located. How did he overcome this problem

moon-letters were a method of writing invented by the dwarves. moon-letters were ordinary runes, but written in such a way that they could only be read when the light of the moon shone behind the writing. some moon-letters could be read by any moonlight, but it was possible to make the writing even more secret. more sophisticated moon-letters could only be read by the light of the same shape of moon, or at the same time of year, as when they were written. hope this !

a constant variable, normally called a controlled variable, is the term for a variable that remains constant throughout an experiment, though other variables may change. an example is the water pressure for a faucet when measuring the amount of water released when the faucet is opened to various increments.