is made of 6 cells. If you touch its two metal contacts with your tongue you feel how dangerous electricity can be.
An electric socket supplies electricity not with 9 but with 220 Volts:  Never evers use electricity from a socket for your experiments!
It may be deadly!
You may connect the battery with the bare ends of two short pieces of bell wire.
Once more touch the ends with your tongue and then dip them into a drop of water. What can you taste and see?