Give a kid a balloon and eventually he or she will figure out how to make it stick to their head by rubbing it against their own hair (But please - do not ask me what my then young son figured out what he could do with his balloon...).
The attractive force generated by rubbing the balloon is known as static electricity. Perhaps the most dramatic effect of static electricity can be seen in a lightning bolt.
When water passes through a magnetic field, it too develops a static electrical charge that is very similar to the child's balloon, or - the lightning bolt. Again, as a reminder, electrical energy is simply the movement of free electrons through a conductive material such as silver, copper, air or water.