Erg derives from the Greek word ‘ergon’ meaning “work” and so an erg is the unit of energy and mechanical work.
It’s equivalent to 1 micro joule, or put another way 1 million ergs equals a joule.
Well it’s about this point that you interject:
“come on Andy, what is a joule then?”
And as I open my mouth you immediately cut in with:
“and don’t try to say one joule is the work done or energy required to exert a force of one newton for a distance of one meter where a newton is the amount of force required to accelerate a mass of one kilogram at a rate of one meter per second squared because I’ll just get lost”.
OK, no problemo, i think i can further simplify this for you. On one of my submarines many years ago I asked our Engineer if he could define ‘erg’ for me and he said:
“An erg is the amount of work done by a mosquito doing a pushup”
Hmmm. Now *that* it is something you can relate to! So now you know that a joule is equal to 1 million mosquito pushups (aka ergs).
BTW, try searching google or live.com for ‘mosquito erg pushup’ and you will see that my engineer at the time was clearly not making it up at the time as i had originally suspected since there are others in the physics world propagating this analogy.
Happy word geeking.