Water Potential: Kinetic or Potential Energy?

Click For Summary

Discussion Overview

The discussion revolves around the concept of water potential, specifically whether it is classified as kinetic energy or potential energy. Participants explore its implications in various contexts, including biology, physics, and chemistry, while addressing definitions and applications.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question whether "water potential" refers to kinetic or potential energy, citing conflicting definitions from different sources.
  • One participant explains that potential energy typically refers to the energy difference between two heights, linking it to kinetic energy gained during a fall.
  • Another participant introduces the idea of water's potential in supporting life and its molecular properties, suggesting a broader interpretation of "potential."
  • Several participants describe water potential in terms of Gibbs free energy, noting that it measures the free energy in a solution and can be seen as a measure of potential energy.
  • One participant emphasizes that water potential is a chemical potential and not an energy itself, although it may resemble potential energy under certain conditions.
  • A later reply seeks to connect the discussion to sodium and potassium potentials in biological systems, particularly in relation to osmotic pressure and neuronal activity.

Areas of Agreement / Disagreement

Participants express differing views on the classification of water potential, with no consensus reached on whether it should be considered kinetic or potential energy. The discussion remains unresolved, with multiple competing interpretations presented.

Contextual Notes

Some definitions and assumptions regarding water potential may vary, and the discussion highlights the complexity of its interpretation across different scientific disciplines.

chound
Messages
163
Reaction score
0
Is water potential the kinetic energy or potential energy of water? Coz my textbook says it potential energy whereas another reference book says ts kietic energy
 
Chemistry news on Phys.org
Excuse me, is this a technical term in biology? Because normally the word potential, used by itself, means potential energy. The potential energy DIFFERENCE between a particle of water at two different heights is the mass of the particle times the height difference. If the particle then FALLS from the heigher height to the lower one, the kinetic energy (energy of motion) that it has gained at the bottom of the fall will equal the potential energy that it has lost; \frac{1}{2}mv^2 = md.
 
selfAdjoint said:
Excuse me, is this a technical term in biology? Because normally the word potential, used by itself, means potential energy. The potential energy DIFFERENCE between a particle of water at two different heights is the mass of the particle times the height difference. If the particle then FALLS from the heigher height to the lower one, the kinetic energy (energy of motion) that it has gained at the bottom of the fall will equal the potential energy that it has lost; \frac{1}{2}mv^2 = md.

Very cool selfAdjoint!:-p

How about the potential water offers for the development of life? Is there a physics formula for that??

It must have to do with the bond and the simple molecular structure of the H20.

Another thing about water I've heard is that it mimics the configuration of any other chemical or solution that enters it. I was told this as an explanation for the mechanism of dissolution or dilution. This would present another potential water holds... in the common use of the word "potential".

Potentially, water (under high pressure) can and is used as a laser to cut stone, wood and even metal. Probably an Egyptian invention:wink: .

Here's a page on "Standard metal cutting processes: laser cutting vs. water jet cutting"

http://www.teskolaser.com/waterjet_cutting.html
 
Last edited:
Water potential (\Psi) is used to describe the osmotic gradient, that fact that water will always move to an area of lower water potential. Water potential can be described in terms of Gibbs free energy;

\Psi = \frac{G}{V}

Where V is the molar volume of water. Water potential is a measure of the free energy in a solution. The lower the water potential the less free energy there is in the system the more potential energy there is. Therefore, water potential can be said to me a measure of potential energy.

~H
 
"Water potential" is nothing but the chemical potential of water in any system where water is a component (eg: in a solution).

\mu_{water} = \left( \frac {\partial G}{\partial n_{water}} \right) _{S,V,n_{others}}

Naturally, since G, the Gibb's Free Energy (or U, H or F, which can also be used in a definition like the one above) is intensive, the "water potential" of pure water (or pure anything else) under standard conditions is 0.

The water potential (or any chemical potential) is not an energy at all, though in some cases it is looks like one. When it does, it seems to resemble a potential energy. This is not, however, to say that it is independent of the KE of particles in the system. It isn't, as is evident if you write the definition in terms of the Helmholtz Free Energy, F(T,V,{n}).

For an equeous solution, the water potential is given by (if you're not too picky about accuracy) the slope of the graph of standard enthalpy of dilution as a function of the mole fraction of water (though usually, the graph is drawn with respect to the mole fraction of the solute).
 
Gokul43201 said:
"Water potential" is nothing but the chemical potential of water in any system where water is a component (eg: in a solution).

\mu_{water} = \left( \frac {\partial G}{\partial n_{water}} \right) _{S,V,n_{others}}

Naturally, since G, the Gibb's Free Energy (or U, H or F, which can also be used in a definition like the one above) is intensive, the "water potential" of pure water (or pure anything else) under standard conditions is 0.

The water potential (or any chemical potential) is not an energy at all, though in some cases it is looks like one. When it does, it seems to resemble a potential energy. This is not, however, to say that it is independent of the KE of particles in the system. It isn't, as is evident if you write the definition in terms of the Helmholtz Free Energy, F(T,V,{n}).

For an equeous solution, the water potential is given by (if you're not too picky about accuracy) the slope of the graph of standard enthalpy of dilution as a function of the mole fraction of water (though usually, the graph is drawn with respect to the mole fraction of the solute).

I stand corrected.

~H
 
Gokul43201 said:
"Water potential" is nothing but the chemical potential of water in any system where water is a component (eg: in a solution).

\mu_{water} = \left( \frac {\partial G}{\partial n_{water}} \right) _{S,V,n_{others}}

Naturally, since G, the Gibb's Free Energy (or U, H or F, which can also be used in a definition like the one above) is intensive, the "water potential" of pure water (or pure anything else) under standard conditions is 0.

The water potential (or any chemical potential) is not an energy at all, though in some cases it is looks like one. When it does, it seems to resemble a potential energy. This is not, however, to say that it is independent of the KE of particles in the system. It isn't, as is evident if you write the definition in terms of the Helmholtz Free Energy, F(T,V,{n}).

For an equeous solution, the water potential is given by (if you're not too picky about accuracy) the slope of the graph of standard enthalpy of dilution as a function of the mole fraction of water (though usually, the graph is drawn with respect to the mole fraction of the solute).


Yo! Heavy duty physics dudes!

Is there a similar equation for Sodium potential or Potassium potential... in reference to the sodium/potassium osmotic "pump" or the osmotic pressure created along a neuron's axon (resulting in em activity)?
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 30 ·
2
Replies
30
Views
2K
  • · Replies 7 ·
Replies
7
Views
264
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 2 ·
Replies
2
Views
1K