Dangerous Done Well: Licking Batteries, Shorting Circuits

For our first day of Dangerous Done Well--an after school class on real-world risk assessment and management--we started with a simple question: will you lick a nine volt battery?

 "Will you lick a nine-volt battery?" The debate rages.

After much debate (and the sight of adult collaborators licking the nine-volts) , about half of the group decided to lick the battery, and felt the odd sensation of their tongue being part of a circuit.

Then we brought out a 12-volt battery, and used a wire to touch the positive and negative terminals to one another. There was a noise and a spark.  

"Would anyone like to lick the 12-volt battery?" 

Of course, the answer was "no". What was the decision-making process that lead us to lick the tiny battery, but not the big one? How did we know that one was safe to attempt, and the other not-so-safe?  

These questions lead us to central pillar of Dangerous Done Well: an explicit procedure for assessing the risks of a dangerous activity, mitigating those risks, and ultimately deciding whether or not the activity can be done safely. (More on the DDW Framework to follow.)

After some research... 

...we learned quite a bit about what happens when you short the circuit of a 12-volt battery, and felt very pleased with our decision to not lick it. And, we experimented with the short circuit. Safely.