I'm running an Electricity merit badge session for my son's boy scout troop. One of the requirements is to make a simple electromagnet. For this, I was going to have the boys take a 12 foot length of 24 gauge wire and wrap it around a large nail and connect it to a AA alkaline cell.
The wire gauge chart tells me that 12 feet of wire is about 0.308 ohms. The nominal voltage of the AA is 1.5 volts, which would put the current at about 4.9 amps. However, when I actually connect it up, the measured voltage of the battery is actually dropping to about 0.9 volts, for a current of about 2.9 amps, which is within the amperage limits of 24 gauge wire.
My question is: Are there any safety concerns with connecting the AA cell this way? I realize that this will drain the energy out of the cell fairly quickly, but it doesn't need to last very long for this demo.