Related Experiment Video
Updated: Jul 2, 2026
07:40
A Gusseted Thermogradient Table to Control Soil Temperatures for Evaluating Plant Growth and Monitoring Soil Processes
Published on: October 22, 2016
Water polarization under thermal gradients.
Fernando Bresme1, Anders Lervik, Dick Bedeaux
1Department of Chemistry, Imperial College London SW7 2AZ, London, United Kingdom. fbresme@imperial.ac.uk
Physical Review Letters
|September 4, 2008
Summary
Thermal gradients polarize water, creating electrostatic fields due to molecular reorientation. This study confirms theoretical predictions, showing significant polarization under extreme temperature gradients.
Area of Science:
- Physical Chemistry
- Computational Physics
Background:
- Understanding water's response to thermal gradients is crucial for various physical and chemical processes.
- Nonequilibrium conditions can induce unique material properties not observed in equilibrium.
Purpose of the Study:
- To investigate the polarization of bulk liquid water under a temperature gradient.
- To analyze the origin and magnitude of the induced electrostatic field.
- To validate findings against nonequilibrium thermodynamics theory.
Main Methods:
- Nonequilibrium molecular dynamics (MD) simulations were employed.
- Simulations focused on bulk liquid water subjected to a temperature gradient.
Main Results:
- A thermal gradient was shown to polarize water molecules along the gradient direction.
- This polarization generates a significant electrostatic field.
- The field's magnitude correlated with the temperature gradient, aligning with theoretical predictions.
Conclusions:
- Water reorientation under nonequilibrium conditions is the source of the induced electrostatic field.
- Temperature gradients of approximately 10^8 K/m can produce electrostatic fields of about 10^6 V/m.
- This phenomenon has implications for understanding water behavior in extreme thermal environments.
Related Concept Videos
01:27Gradient Fields
A gradient field is a vector field derived from a scalar field. A scalar field assigns a single numerical value to every point in space, such as temperature, pressure, or electric potential. The gradient field describes how that value changes from point to point. It gives both the direction of the fastest increase and the rate of change in that direction.For a scalar field f(x, y), the gradient is written as\begin{equation*}\nabla f=\left\langle \jfrac{\partial f}{\partial x},\jfrac{\partial...
01:26What is an Electrochemical Gradient?
Adenosine triphosphate, or ATP, is considered the primary energy source in cells. However, energy can also be stored in the electrochemical gradient of an ion across the plasma membrane, which is determined by two factors: its chemical and electrical gradients.The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an ion’s...
02:42Aqueous Solutions and Heats of Hydration
Water and other polar molecules are attracted to ions. The electrostatic attraction between an ion and a molecule with a dipole is called an ion-dipole attraction. These attractions play an important role in the dissolution of ionic compounds in water.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
01:16Solubility Equilibria: Ionic Product of Water
Pure water is a weak electrolyte; only a small amount ionizes into hydrogen and hydroxide ions. At any given temperature, the concentration of undissociated water is almost constant, so the ionic product of water is the product of the hydrogen and hydroxide ion concentrations, denoted as Kw. The square root of Kw gives the individual ion concentrations.
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le Chatelier's...
The ionic product of water varies with temperature, and its value is 1.0 x 10−14 at standard experimental conditions. Per Le Chatelier's...
02:40Osmosis and Osmotic Pressure of Solutions
A number of natural and synthetic materials exhibit selective permeation, meaning that only molecules or ions of a certain size, shape, polarity, charge, and so forth, are capable of passing through (permeating) the material. Biological cell membranes provide elegant examples of selective permeation in nature, while dialysis tubing used to remove metabolic wastes from blood is a more simplistic technological example. Regardless of how they may be fabricated, these materials are generally...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...