Re: Bruce's TPU Theory and Experiments - understanding field lines

[MileHigh]

Penno64:

Sorry, your link is not helping me at all.

TK:

They are not closed loops, they are leaving one disk and landing on another disk.  They are the path that a massless electrical charge would take in the electric field.  The electric field lines are at right angles to any virtual equipotential surface that exists in empty space between the disks.

Although it's not too clear because it's a crappy 240p video, the dead giveaway is that the lines leave/land on the disks at right angles to the surfaces of the disks.

But if you plot "attraction" or "repulsion" electric field lines they look just about like magnetic field lines.

I am going to assume the following:

Two standard bar magnets facing each other in repulsion:   [S****N]     [N****S]

Two rectangular metal bars facing each other both positively charged:   [+++++]     [+++++]

If you only look at the localized volume between the ends of the bars in close proximity, the lines of force will look somewhat similar.  The giveaway will be that the electric lines of force must exit the surfaces of the metal bars at right angles vs. that not being a requirement for the magnetic lines of force.

When you look at the rest of the volume they are completely dissimilar.  Plus you still can't forget the basics.  Both magnets create field lines that are closed loops right out to the limit of infinity.  Both charged metal bars create field lines that extend straight out to the limit of infinity and there are no closed loops.

These two clips are not a perfect match for this discussion but they are close:

http://www.youtube.com/watch?v=1I0EQzP8nBs
http://www.youtube.com/watch?v=cxTS1T6f13I

MileHigh

[MileHigh]

Just something to perhaps help beginners:

there really isn't any such thing as a "field line"

There is no literal field "line."  However what there literally is at any point in 3D space is a vector for either an electric field or a magnetic field.  A vector has magnitude and direction, and you can visualize it as a little arrow in 3D space that has size and direction.

Since each little arrow has direction, and you can imagine a 3D matrix of millions of arrows, each one at a different position, then the arrows will line up and form a "path."  That "lined up path of arrows" is the imaginary field line.  The important point being that at any position on the imaginary field line, there is a real little electric field or magnetic field vector that is lined up with the field line. 

[tinman]

Well i did state in my answer that the shown field line's jump from one magnet to the opposite pole of the other magnet,insted of looping around to the opposite pole of the same magnet-that has to be worth half an apple lol.

[MileHigh]

Some extra information for fun.   For electric fields:

The diagram below illustrates the field lines of force associated with the electric field between charges, where (a) shows the field lines connecting a negative-positive charge pair, while (b) shows the field lines separating two positive charges. The main rules that define the behaviour and properties of these field lines are listed as follows:

   
• Electric field lines start on positive charges and end on negative charges.
• The density of electric field lines indicates the strength of the E field in a particular region. The field is stronger where the lines get closer together.
• Field-lines never cross and never merge.
• Field lines connect perpendicularly to the source and sink charges.
• The direction of the electric force at any point on the field line must form a tangent to the field line.

[MileHigh]

Now for magnets.  Not that the magnetic fields do not have to enter or leave the magnets at a right angle to the surface of the magnet.