energy types

mather

hello!

I would like to know, which are all the energy types, force types, field types, wave types, particle/material types?

i ask this, because i was told recently that van der walls forces/field/energy is not electric (either electrostatic or electromagnetic)

thanks!

Bobbywhy

mather, I think you don't need anyone to list "all the energy types, force types, field types, wave types, particle/material types" to get answers. For a clear overview of Van der Waals forces have you studied this yet?
http://en.wikipedia.org/wiki/Van_der_Waals_force

If you learn everything on this page you can get to more detailed explanations by clicking on those "blue" (links) terms within the article and also by using the references at the end.

There are lots of other sources of explanations using "Google" search.

mather

I still cant get it.
What else can be, if not gravity, electricity, electromagnetism?

Drakkith

Kinetic energy, thermal energy, electrical energy, and a dozen other terms. All of it really boils down to the 4 fundamental forces. We just use more terms to refer to specific examples of energy to make it easier to work with.

Bobbywhy

mather, I am not an expert, but as I read these sources it seems that the van der Waals forces are indeed mediated by electrical fields...both attraction and repulsion.

“van der Waals forces
The attractive or repulsive forces between molecular entities (or between groups within the same molecular entity) other than those due to bond formation or to the electrostatic interaction of ions or of ionic groups with one another or with neutral molecules. The term includes: dipole–dipole, dipole-induced dipole and London (instantaneous induced dipole-induced dipole) forces. The term is sometimes used loosely for the totality of nonspecific attractive or repulsive intermolecular forces.”
http://goldbook.iupac.org/V06597.html

Here are a few more websites for you to study:

http://hyperphysics.phy-astr.gsu.edu...ical/waal.html
http://www.chemguide.co.uk/atoms/bonding/vdw.html
http://antoine.frostburg.edu/chem/se...n-forces.shtml

Finally, here is an easy to read and excellent description of the van der Waals force:
http://www.britannica.com/EBchecked/...r-Waals-forces

mather

in deed this is excellent and concise

the question is... do I miss something that I still think these forces are due to electric charged subatomic particles, thus they are electrostatic/electromagnetic?

Studiot

Mather,

Perhaps if you posted the exact nature of what you were told?

Did you respondent mean that Vander Walls and (London) forces are the result of statistical averages of short term electrical interactions, in much the same way that pressure is the result of short term momentum interactions in gasses?

Or did she mean that the Van Der Walls equations was the first to recognise that a correction to the ideal gas equation was necessary to acount for the fact that molecules occupy space?

Or.....?

mather

sorry but this is not the english i can comprehend

Studiot

Please post exactly what was said.

mather

That van der wals are not electric forces.
There is a possibility that he said van der wals are not electrostatical or maybe electromagnetical forces.

Studiot

So do you understand the kinetic theory of gasses about how the pressure on the walls comes about?

mather

I suppose it is because of the thermal/Brown movement of the molecules of the gas.

I dont know what is the source of that kinetic energy. I know that it increases with heat. But I dont know the quantum/submolecule mechanism of it.

Studiot

The kinetic theory is not a quantum or any fancy upmarket theory.

It is just about representing the molecules as little balls bouncing around.

As they bounce around they will bump into each other and into the container walls.

As they bounce around they have a range of velocities and the velocity of individual molecules changes as they bump into things.

As with any range of quantities we can represent this by an average velocity.

Bumping into each other only causes changes within the gas so we are not interested in that here.

Bumping into the walls, however, exerts a force on the walls. the greater their velocity the greater their impact force.

Since there are lots of molecules we can calculate an average force using the average velocity.

We call this average force the pressure.


The point of all this is that we can attribute the pressure of say 5 pascals to the average effect of the momentary bumping of the molecules in to the walls.

I hope this helps because VDW forces have a similar average basis which we can move on to.

The_Duck

That's wrong; Van der Waals forces are indeed electromagnetic.

mather

Okay then I understand that van der wals are actually electromagnetic forces

Their source is the movement of electrons around the nuclei of a molecule, which movement makes the molecule be a specific dipole, tripole, etc (according to the structure of the molecule) at a specific time.

As for thermal energy, how does it increase the kinetic energy of a molecule?

Which is the velocity of a molecule in void or where there is no thermal energy at all?

Studiot

I don't know what to say since your response doesn't seem to have anything to do with my last post.

Am I wasting my time?

mather

No, i thought that i understood you and i said what i exactly understood in my last post, isnt it correct?

As for heat and molecular velocities, maybe it's another topic