The USGS Water Science School
You may think this is a picture of a dirty old truck... but actually this is a modern, high-tech piece of equipment that uses an ancient methodology to drill a well! The drilling being done here is using a "cable tool" to drill through earth and rock. The bit head is at the end of a flexible cable and as the drill gets further down in the rock more cable is played out.
Another method of well drilling uses a drill head (the "bit") at the end of a metal tube. The bit starts drilling a hole in the ground by either chewing or smashing the rock. As the bit chews more and more rock, more piping is added, creating a very long metal tube with the drill bit at the end. Wells more than 1,000 feet deep can be dug using this method.