About a battery's positive terminal Does the positive terminal of the battery mean that the concentration of electrons is more there. In some places people say that current moves from positive to negative and they call it a convention what does this really mean and others say it flows from negative to positive it's really confusing.
 A: The names 'positive' and 'negative' were assigned to charges long before protons and electrons were discovered and even before batteries were invented. The type of charge that glass acquired when rubbed with silk was called 'positive', and the type that amber acquired when rubbed with fur was called 'negative'.
In the early 1800s batteries were invented and found to have opposite charges on their terminals. Hence their designations as 'negative' and 'positive' terminals. When wires were connected across the terminals, heating effects and (in the 1820s) magnetic effects were found and (in conjunction with the running down of the battery) attributed to a flow of charge through the wires. But no-one could know whether it was positive or negative charge or even both that was flowing. [The Hall effect had not been discovered, and few believed that atoms existed, let alone that there was such a thing as atomic structure.] So the decision was made to assume arbitrarily that it was positive charge that flowed through a metal wire from the positive battery terminal to the negative terminal. The 'hand rules' (invented in the later 1800s) that we can use in electromagnetism are based on this so-called conventional current.
In the 1890s, the negatively charged particles that we now call 'electrons' were discovered.  [Remember: negatively charged meant having the same kind of charge as amber rubbed with fur!] Within the next few years atomic structure came to be understood as electrons surrounding a nucleus, and electric current in a metal wire, as a flow of electrons. They flow from the negative battery terminal (with an excess of electrons) through the rest of the circuit to the positive terminal (with an electron deficit). Life would have been easier for 20th and 21st century high school students if, back in the 1700s, the decision had been made to call the type of charge that amber acquired when rubbed with fur 'positive'!
