# Naked Science Forum

## Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: felixtheferret on 08/06/2007 23:37:09

Title: Expressing simple electrical theory correctly in English
Post by: felixtheferret on 08/06/2007 23:37:09
Hi gurus.
Hopefully this should be an easy one :  I am having
trouble finding the correct word, in English, to describe
a simple equation, concerning Energy,  Power, and Time:

Power =  Energy       or, with units:             Watts  =  Joules
------                                             ------
Time                                               Seconds

So how do you explain the term 'Power,' in English, to the layman?  The answer of course,  Energy divided by Time,  is expressed in English typically as "the RATE of expenditure of energy."  So far so good.

But what if we want to use a common English term to describe Energy in terms
of power ?

So, turn the equation around and we get :

Energy =  Power * Time

So if Energy equals Power multiplied by Time,  what is the elegant
way of expressing this multiplication-by-time relationship in English?

"Divided by Time"  becomes "Rate" in the first example.  This is because
the word 'rate' means, not 'division,'  but  'division by time.'

What can I use as a substitute for "Multiplied by Time?"
please don't suggest "product" as this word is nothing to do with Time
as a quantity, unlike the word 'rate.'
I need an English word that conveys the meaning of this multiplied-by-time relationship, not just an alternative word for "multiplied by."

My only guess so far is 'time-spread.'

Basically,  I want to say something like this:

Energy is the 'time-spread' of power, or with units,
"One Joule is the time-spread of power."

There must be an official English word for this, used in science.

In maths, the terms are just joined with a hyphen:
1 joule = 1 watt-second
pronounced
"one joule equals one watt second."

However this does not convey anything like the same meaning
as the word 'rate' does for 'divided by time.'

help!

Title: Expressing simple electrical theory correctly in English
Post by: Batroost on 08/06/2007 23:49:04
I always found the most English-Friendly expression to be "work-done".

Most people seem to have an inutitive grasp of the relationships between "work", "power" and "time".

Or put another way... Energy is the work-done by a given power acting over a given time.
Title: Expressing simple electrical theory correctly in English
Post by: felixtheferret on 18/06/2007 22:50:00
Hi Batroost,
thanks for the suggestion,  I think you have identified the problem:
"work-done OVER time."   There's the problem word!  "Over!"   Because 'over'
is ambiguous - what you mean is "during a period of time"  whereas 'over' gives
me a sense of 'division'  e.g.  eight over 2 (over the division bar) gives 4.

So maybe 'during' is a possibility?   I didn't think of that last time :

Energy = work done during a period of time ?
Energy = work done for the sum duration of a period of time ?

what do you think?
:-)
thanks...

Title: Expressing simple electrical theory correctly in English
Post by: Batroost on 19/06/2007 19:30:55
Quote
Energy = work done during a period of time

I like this.

Cheers,

Batroost
Title: Expressing simple electrical theory correctly in English
Post by: Bored chemist on 19/06/2007 20:09:24
"Energy = work done during a period of time"
Presumably this is to distinguish it from work that is done during no period of time?
Err, no that's silly.
Energy = work done
or, as I was taught at school

Energy is the capacity to do work
Title: Expressing simple electrical theory correctly in English
Post by: Batroost on 19/06/2007 21:31:19
Quote
Energy is the capacity to do work

This is true, but only if you're looking into the future. The question was more about looking into the past i.e. what has happened.

Er... yes, I konw that theoretically, then energy is capable of doing more work but I don't think that is what felix is after.
Title: Expressing simple electrical theory correctly in English
Post by: lyner on 27/06/2007 12:09:37
Why the insistence on 'word equations' and cuddly explanations?
Science is just not that simple.
Energy, work, power etc. are quite sophisticated ideas and need precise definitions so that we all know what everyone means.
You wouldn't expect to describe Integral Calculus in simple everyday terms -  except to  discuss its aims. Nor would you restrict yourself to everyday terms for medicine  or economics; it's so limiting.
The problem with over-simplification is that it can lead people to wrong conclusions and mistakes. If you 'can't get the maths' of a situation, you will probably not, actually 'get the situation' either.
Maths was a real gift for scientists and engineers - let's use it and avoid confusion.
I really am not just being elitist!