I'm reading about electroreception in fish

  • Thread starter Thread starter Minimaster
  • Start date Start date
  • Tags Tags
    Reading
AI Thread Summary
Electroreception in fish involves detecting electric fields generated by specialized organs, as seen in the example of a fish with an electric organ in its tail. The electric field produced is influenced by the conductivity of surrounding materials, such as plants and stones in the sea. When an electric field interacts with these objects, it is expected that the conductivity will be lower, leading to increased resistance and a decrease in current detected by the fish. This means that the electric field will be distorted as it passes through these materials. Understanding these interactions is crucial for comprehending how fish navigate and sense their environment.
Minimaster
Messages
1
Reaction score
0
Im reading about electroreception in fish, so I wanted to check something. If you look at the http://img94.imageshack.us/i/capturesrt.jpg/" you see this fish has some kind of electric organ in its tail which produces an electric field. That field is then detected on the front part of the body.
As far as I know, if I place a conductor in el. field Ill get something like http://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/VFPt_superconductor_ball_E-field.svg/120px-VFPt_superconductor_ball_E-field.svg.png" that depends on the permittivity but the field inside won't be zero.

So, what kind of distorsion would you expect to happen to E field while passing through plants or stones in the sea?

thanks
 
Last edited by a moderator:
Physics news on Phys.org


Minimaster said:
Im reading about electroreception in fish, so I wanted to check something. If you look at the http://img94.imageshack.us/i/capturesrt.jpg/" you see this fish has some kind of electric organ in its tail which produces an electric field. That field is then detected on the front part of the body.
As far as I know, if I place a conductor in el. field Ill get something like http://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/VFPt_superconductor_ball_E-field.svg/120px-VFPt_superconductor_ball_E-field.svg.png" that depends on the permittivity but the field inside won't be zero.

So, what kind of distorsion would you expect to happen to E field while passing through plants or stones in the sea?
Welcome to PF.

You have shown us a diagram of electric field lines when a spherical conductor is placed in a uniform electric field, such as one produced by two large parallel charged plates. This is quite different than the electric field produced by an electric eel.

The eel does not feel the electric field directly. If feels changes in current. It creates a potential difference between its tail and its nose and detects the amount of current in its nose. That will vary depending on the conductivity of its immediate surroundings.

I would expect that plants and stones would have lower conductivity (increase resistance) so the current would decrease when passing close to such objects.

AM
 
Last edited by a moderator:
This is from Griffiths' Electrodynamics, 3rd edition, page 352. I am trying to calculate the divergence of the Maxwell stress tensor. The tensor is given as ##T_{ij} =\epsilon_0 (E_iE_j-\frac 1 2 \delta_{ij} E^2)+\frac 1 {\mu_0}(B_iB_j-\frac 1 2 \delta_{ij} B^2)##. To make things easier, I just want to focus on the part with the electrical field, i.e. I want to find the divergence of ##E_{ij}=E_iE_j-\frac 1 2 \delta_{ij}E^2##. In matrix form, this tensor should look like this...
Thread 'Applying the Gauss (1835) formula for force between 2 parallel DC currents'
Please can anyone either:- (1) point me to a derivation of the perpendicular force (Fy) between two very long parallel wires carrying steady currents utilising the formula of Gauss for the force F along the line r between 2 charges? Or alternatively (2) point out where I have gone wrong in my method? I am having problems with calculating the direction and magnitude of the force as expected from modern (Biot-Savart-Maxwell-Lorentz) formula. Here is my method and results so far:- This...
Back
Top