©2019 L A Waygood
What do we mean by ‘electricity’?
How often have you read a newspaper report, describing an accident in which ‘…electricity surged through the victim’s arm!’ ?
Using the term, ‘electricity’, in this way is wrong, but reinforced by journalists and others with little or no science background.
So, what is this ‘thing’ we call, ‘electricity‘? What was it, exactly, that ‘surged through the victim’s arm…’ ?
Was it ‘charge‘, perhaps? Or was it ‘current‘? Or, perhaps, it was ‘energy‘? Or was it something else entirely?
The problem is that the word, ‘electricity‘, is widely used by the layman to mean any or all those things. But for those of us who are studying electrical science, this can be a problem as we need to be more specific.
What ‘electricity’ isn’t
Until well into the 1960s, scientists took ‘electricity’ to mean what we now call ‘charge‘, a quantity we measure in coulombs. If you read a textbook from that period, you will likely see the expression: ‘quantity of electricity, expressed in coulombs’. These days, that would read: ‘quantity of charge, expressed in coulombs’.
We also hear people say, ‘Electricity flows through a conductor…’. But if electricity is another word for ‘charge’, can it also be used to mean a ‘flow of charges’ —i.e. current? After all, ‘charge’ and ‘current’ are two different things, so can we really use ‘electricity’ to mean both?
And how many times have we heard that ‘Batteries and capacitors store electricity…’ ? Or that ‘My meter measures how much electricity I use…’. Actually, cells and batteries store energy, not ‘electricity’. And our ‘meter’ measures how much energy we use expressed, in this context, in kilowatt hours.
It seems, then, that ‘electricity‘ is widely-used to describe charge, current, and energy (and, no doubt, other quantities as well!). But these are completely-different quantities, measured using completely-different units. Obviously, this one word, ‘electricity’, cannot mean all these completely-different things as though they were the same!
So what, then, is ‘electricity‘?
What ‘electricity’ is
The answer is pretty straightforward. ‘Electricity‘ isn’t some sort of ‘stuff’ that we can measure or use. It isn’t a quantity that we measure and apply units of measure to. So it isn’t an alternative name for ‘charge’, ‘current’, ‘energy’, or any other quantity come to that.
The term, ‘electricity‘, encompasses a whole range of interrelated phenomena. So it is best-described as the name we give to a branch of science, in exactly the same way as we use: ‘chemistry’, ‘biology’, ‘mechanics’, ‘thermodynamics’, or ‘astronomy’. We study ‘electricity‘, or ‘electrical science‘.
‘Electricity’ is simply the name we give to a branch of science.
We can also use ‘electricity‘ together with its related term, ‘electrical‘, as an adjective. For example: ‘electric charge‘, ‘electric current‘, or ‘electrical energy‘. We can also use it to distinguish between related phenomena, such as ‘electric fields‘ as opposed to, say, ‘magnetic fields’.
And, when we say ‘electricity meter’ to describe that meter on the wall of our homes, what is that meter actually measuring? The answer is energy. So, to be accurate, we should describe it as an ‘energy meter’.
So, it is a misconception to believe that ‘electricity’ is some sort of ‘stuff’ that flows through wires, or is stored in batteries, or is generated in power stations, or is ANYTHING that we can measure. So, it’s important that we only use ‘electricity‘ to describe a subject, and NOT a measurable quantity.