Connect a wire to each electrical contact of the bulb. The electrical contacts may be metal prongs sticking out from the base of the bulb or a screw arrangement and round dot at the bottom of the bulb. Use two pieces of 10-inch wire and connect each to a contact on the bulb.
Connect one of the 10-inch wires from the bulb to a fluorescent starter. This is a small cylindrical device and is available in most hardware stores. The starter has two metal contacts protruding from the top; let’s call them prongs 1 and 2. The wire from the bulb should be connected to prong 1 on the starter.
Connect a new piece of wire to prong 2 on the starter. The other end of this wire will be connected to the negative terminal of one of the batteries. Leave it unconnected for now.
Connect the other 10-inch wire from the bulb to the positive terminal of one of the batteries; we’ll call this battery A. The terminals of the 6-volt batteries are metal springs located at the top. Take the 10-inch wire and connect it to the spring marked ‘+’ on the battery. At this point, one end of the wire is connected to an electrical contact on the bulb and the other is connected to the positive terminal of battery A.
Connect a final piece of wire from the negative terminal of battery A to the positive terminal of battery B. This arrangement is called connecting two batteries “in series.” Each of the 6-volt batteries now acts as a single, more powerful battery, delivering a total of 12 volts – the same voltage as the bulb. If you were using a 3-volt bulb, you would connect two 1.5-volt batteries in series.
Connect the free end of the wire from Step 3 to the negative terminal of battery B. The simple circuit is now complete and the bulb should light up and start flickering.