# Trouble understanding flux

Discussion in 'General Science' started by omgadoggie, Jun 9, 2016.

Apr 16, 2016
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so i'm studying what flux is and i just want to make sure i understand it correctly. it can either refer to a single vector component, say like a beam of light, emerging from some singularity over some amount of time... OR the total amount of light emerging over some amount of time from a given surface, right? correct me if i'm wrong
so then if i were to think about some amount of charge, flowing through some amount of time, that would be current... but if i were to think about some amount of charge, flowing through some amount of time over/through some surface, then that would be flux, correct?
just need to make sure i understand this properly

2. ### nsaspook AAC Fanatic!

Aug 27, 2009
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"Flux" is a word that can mean just about any and everything today.
https://simple.wikipedia.org/wiki/Flux

This is electrical 'flux' (surface integral, usually the second definition).

The water analogy 'Current flow' flux of the first definition (transport phenomena, electric current a rate of flow).

3. ### JoeJester AAC Fanatic!

Apr 26, 2005
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There are many applications for that word.

4. ### BR-549 AAC Fanatic!

Sep 22, 2013
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Flux is a word that describes density (area) and usually the velocity of a concentration of matter or force......or a property of such.
The concentration doesn't have to be moving, but usually is. A charged cap has a stationary flux.

The wind is a flux. The salt concentration in a glass of still water can be described as a flux. Our galaxy is a flux of stars.

The force of gravity, the electric and magnetic force can be described as a flux. Current is a flux, as is voltage.

As the flux moves, (density and velocity), it can also have handedness. It can rotate, left or right. Even if the flux does not move forward, it may still rotate.

So, flux has density, (sometimes called magnitude), velocity, rotation and duration or rate of change.

Modern math definitions of flux are incomplete and do not fully describe the properties of flux.

Rotation for example, ( a component perpendicular to velocity, handedness) which can be magnitudes greater than velocity, is totally ignored. The radius or reference for the rotation can be external or internal to the flux area. An angular or lateral vector along with the velocity vector for flux.

This ignored handedness of the gravitational force (flux) and the handedness of the electromagnetic force (flux), is what relates and unifies these two forces.

5. ### wayneh Expert

Sep 9, 2010
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Flux is something per unit area. As a chemical engineer, it's common to talk about a mass or heat flux across some area. In electronics the units may be different but I think it's still per unit area.

An alternate definition is exemplified by "X is in a state of flux". It implies constant change, but doesn't involve any physical units except perhaps time.