There is a two way movement of electricity as it moves. When stream move in one direction while electrons moving opposite direction. For example , for the end of a battery energy , - and + terminals must be synchronized between the potential. The soil is completely different.Soil is never work with synchronization logic. Soil work, if electricity + or – it will get directly neutralizes. If there is a lot of + or - electricity in object it will immersing if there is less electricity it will send until synchronize. Car engine Works with this system.