You will need the following: a tap, a watch battery, a micro switch, a green LED, hot glue and the gun for it, a solderer, a plastic pacifier, shrink tubing, wires, a drill, adhesive tape, and a pair of nippers.
First, break the pacifier because you only need its tip. Fill it with hot glue and put the green LED there while the glue is still hot. Leave the LED’s contact elements outside.
Drill a hole for the micro switch.
Make a block of three watch batteries and connect the switch. Always insulate the connections with adhesive tape or shrink tubing.
Make the final touch.
This is a simple way to make a light bulb. You can make it switch on and off by switching the tap if you want.