In Metroid Prime, you must defeat the Cloaked Drone in order to unlock a grid below the floor. There, you must enter a small hole with your morph ball and manouvere around a maze without touching the electric. While you're moving around, you'll come across puddles of water. Lay a bomb to destroy some of the electricity and continue navigating through the maze. Once you finally reach the end, you'll obtain the Power Bombs. These are useful for destroying bendezium blocking certain areas. They do, however, use ammo, so use wisely.