Why does electricity flow?

Electricity - what is it actually?

• Regardless of whether it is electricity from the socket or from rechargeable batteries and batteries, electricity is always charged in motion.
• In the simplest case, a current flowing through a metallic conductor is negatively charged electrons.
• In the case of a battery, these electrons move from the negative pole of the battery (negative pole) via a conductor (perhaps even with a consumer, such as a lamp or a small motor) to the positive pole of the battery (Positive pole).
• But be careful: For historical reasons (the electron was not yet known), the technical direction of the current was determined from plus to minus, i.e. against the direction of movement of the electrons. So you have to pay attention to whether you are talking about electricity or charges.

Separate charges and electricity flows

• The reason that a current flows through a line is first and foremost a power source, for example a battery.


Why does the current flow into the earth?

Lightning rods, tram tracks or house lines show it: electricity flows in ...

• In this battery, a chemical reaction ensured that charges in an electrolyte solution were separated and accumulated at the two different poles of this battery.
• The prerequisite for current to flow are therefore always separate charges that want to balance each other.
• A measure of this is the electrical voltage of a power source. The higher this is, the greater the desire - to put it simply - that the separate charges balance each other.
• If you now ensure that a conductive material (i. A. a metal, but also an acid or lye) for connection between the two poles with the charges cares, the mobile charges (in metal it is the electrons) will set themselves in motion - electricity flows.

Separating charges and letting electricity flow - a simple experiment

You are probably familiar with this simple experiment, even if the physical background is usually less known:

• Charge can be separated by friction. Regardless of whether you rub a rubber stick with a woolen cloth, run a piece of fabric over the surface of a balloon or with Plastic soles run over a synthetic fiber carpet: Abrasion always creates charges on the surfaces of the objects involved separated.
• It can happen that you are "uploaded" yourself while walking on the carpet.
• Now grab something metallic, regardless of whether it is the handle of a door or the lock on the car: The charges flow off via the electrical conductor, the metal. Of course, a current also flows during this discharge process, albeit a small one.
• An experiment from school: the charges separated by friction can be detected on an electroscope.

By the way: Even before a thunderstorm, charges are separated by friction between the water droplets - the thundercloud is charged against the surface of the earth. In the case of lightning, the charge is equalized - a high current flows.