When the "Shack" didn't have single AA battery holders in stock for my 4-H project, I whipped this up.
It's a single AA holder with a receptacle for a small bulb. The channel along the side holds the connecting wire and by feeding the wires through the holes, acts as a strain-relief.
Use it to see what can conduct electricity!
Strip some solid copper wire - e.g. a solid conductor from a Cat-5 cable. Feed it through the end-holes a few times to make the battery contact. Do the same for the other side.
Pop a 1.5v bulb in the receptacle (RS 272-1139). Twist one end of the bulb's wire around one of the battery contacts.
Feed stranded wire up and through a few of the holes in the side channel for strain relief. Connect one wire to the other battery contact. Connect the second wire to other end of the bulb.
Optionally add alligator clips to the end of the probe wires.