I'm currently doing a biology experiment with earthworms, testing how they react to EM fields. My question is, what kind of EM field does a 6 volt battery give off with a closed circuit? And, how far does that EM field extend?

impossible to determine.

 

you should at least provide the current potential with the voltage.

I don't have a strong background in physics. I'm a biology major in college. What is a current potential?

how much current (Amps) can the battery deliver at any one time.

you then simply multiply that by 6 to get the Power in Watts, that will be the theoretical Max you can get out of it.

I think we are missing something here...