Gave my son a 9 volt battery today...

[Mike Johnson]

You might be interested in the book "Fifty Dangerous Things (You Should let Your Children Do)" by Gever Tulley.



http://www.amazon.com/Fifty-Dangerous-Th...984296107/

[mikebw]

If you've never opened up the casing on a 9V battery you should try it. Inside are 6 little 1.5v batteries, similar to a AAA but smaller I think. This is a great demonstration of how voltage sources are additive when placed in series. 9V batteries are also cool because you can plug the + of one battery into the - of the other without any extra wire or fasterners. Given enough batteries you can add up to quite a voltage!

[BernDog]

mikebw wrote:
Inside are 6 little 1.5v batteries, similar to a AAA but smaller I think.

I think they're actually considered AAAA.