Science: The Young Rocketeers

"It was just sitting there," said Johnny Easley, 16, of San Angelo, Texas, "and all of a sudden it wasn't." Johnny and his friend Billy Hembree, 17, were sent to a hospital last week with minor injuries after trying to fly their do-it-yourself rocket, a 2-ft. copper tube filled with a mixture of zinc dust and sulphur. They lit it and ran. "It was just like the Flopnik [Vanguard]," said Billy, "going great at first. Then it just folded." When they returned to investigate, the rocket exploded. Johnny and Billy were lucky; a few...