Ensure Safety in the Laboratory A base with a light bulb and two long prongs sits above a beaker partially filled with liquid; the prongs extend into the liquid. To the right, 2 wires extend from a source labeled Power; 1 attaches to the base and 1 to the right-hand prong. On the left, 2 wires are attached to the terminals of a battery, with 1 wire attached to the base and 1 to the left-hand prong. In a conductivity apparatus, like the one above, you should never touch the while the power is on.