How does metal conduct electricity 1

Explanation: Why and how metals conduct electricity

Due to the metal bond, freely movable electrons are present in the metal. So they can transport the electrical energy from the minus pole to the plus pole. In order for electrical energy to be transported, freely movable electrons are required (see “What is electrical current?”). Only mobile electrons are able to “work”, i.e. to transport electrical energy from the negative to the positive pole. Thanks to the formation of the metal bond, freely movable electrons are sufficiently present in metals. That is why metals conduct electricity. Other materials such as wood or plastic do not form a metal bond or something corresponding. As a result, there are no free, mobile electrical charge carriers in these substances either and therefore they do not conduct electrical current. There are freely mobile electrons everywhere in the metal. Each one carries a small portion of energy. If you close the metal in a circuit, the plus pole pulls the electrons towards it. New mobile electrons with energy move up from the minus pole of the voltage source. In order for the energy transport to go faster, the electrons also give their energy further forward. Unfortunately, an overly simplified model of "charge transport in an electric circuit" is often taught at school. This often leads to misconceptions. Many people imagine the following in everyday life: “The power cable (metal) is a kind of race track. The runners are the electrons that are sent off at the start (minus pole) and then run towards the goal (plus pole). On the way they pass a lamp, for example, and give off their energy there. On the racetrack, i.e. there is nothing in the metal. ”Basically, this is a very nice idea. However, if you take a closer look at this, you have to recognize that it is unfortunately wrong. This is mainly because electrons are real “snails”. They move forward in a circuit at just 1 mm per second. This is a very long distance for its tiny size, but if the idea were correct, it would mean the following for us: If a power cable were 1 m = 1,000 mm long, a lamp, for example, would only light up after 1,000 seconds. That's around 17 minutes. The electricity generated by wind farms in northern Germany would not arrive in the south for a distance of 500 km for about 15 years. We know from everyday life that this is not the case and we owe it to the electron gas in the power cable.

How is it right

Electrons in the form of electron gas are already present throughout the metal. Each of them has a small energy package with it. If you close a circuit, this is the “starting shot” for all electrons to move towards the plus pole at the same time. More precisely, the plus pole attracts the electrons. After less than a fraction of a second, the first electron can release its energy to a consumer (for example a lamp). The lamp has immediate energy and can shine. It doesn't have to wait for energy. During this process, the minus pole sends a new electron and energy package into the metal for each electron that ultimately arrives at the plus pole. As a result, the number of electrons in the metal, i.e. in the cable, always remains the same. So it cannot happen that at some point the electron gas is missing somewhere in the cable and the metal (cable) falls apart. In order for the energy to arrive even faster, the electrons help each other with another trick. They pass on their energy at a speed of around 200,000 km / s (66% speed of light), similar to a transport chain. The latter fact is the reason why “alternating current” can also transmit electrical energy. If the electrons did not pass on their energy like in a transport chain, the energy would remain in place.
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