We all know very well that electricity is a directed flow of charged particles as a result of an electric field. Any student will tell you this. But the question of what is the direction of the current and where these very particles go can confuse many.
The heart of the matter
As you know, in a conductor, electricity is carried by electrons, in electrolytes - by cations and anions (or simply ions), in semiconductors, electrons work with so-called "holes", in gases - ions with electrons. Its electrical conductivity depends on the presence of free elementary particles in a particular material. In the absence of an electric field in a metal conductor, current will not flow. But as soon as a potential difference arises in its two sections, i.e. voltage will appear, chaos will stop in the movement of electrons and order will come: they will start to repel the minus and head towards the plus. It would seem that this is the answer to the question "What is the direction of the current?". But it was not there. It is enough to look in the encyclopedic dictionary or just in any textbookin physics, as soon as a certain contradiction becomes noticeable. It says that conventionally the phrase "current direction" denotes the directed movement of positive charges, in other words: from plus to minus. How to deal with this statement? After all, there is a contradiction visible to the naked eye!
Power of habit
When people learned how to make a DC circuit, they did not yet know about the existence of an electron. Moreover, at that time they did not suspect that it was moving from minus to plus. When Ampere proposed in the first half of the 19th century the direction of the current from plus to minus, everyone took it for granted and no one challenged this decision. It took 70 years until people found out that the current in metals is due to the movements of electrons. And when they realized this (it happened in 1916), everyone was so used to the choice made by Ampere that they did not change anything.
Golden Mean
In electrolytes, negatively charged particles move towards the cathode, while positive particles move towards the anode. The same thing happens in gases. If you think about what direction the current will be in this case, only one option comes to mind: the movement of bipolar electric charges in a closed circuit occurs towards each other. If we accept this statement as a basis, then it will remove the current contradiction. It may come as a surprise, but more than 70 years ago, scientists received documentary evidence that opposite in signelectric charges in a conducting medium actually move towards each other. This statement will be true for any conductor, regardless of its type: metal, gas, electrolyte, semiconductor. Be that as it may, it remains to be hoped that over time, physicists will eliminate confusion in terminology and accept an unambiguous definition of what the direction of current movement is after all. Of course, it is difficult to change a habit, but you must finally put everything in its place.
