Finally, Lex Luthor challenges Superman to place one end of a 33 foot long vertical pipe into the river, fly up to the other end, and draw river water up the tube with his mouth. Unfortunately, even though the Last Son of Krypton can form a perfect vacuum inside his cheeks, he cannot complete this challenge and he is honor-bound to let Lex Luthor go. Explain how Lex was able to foil Superman.
