Confusion created by notation in E&M

Click For Summary
The discussion highlights significant confusion among students regarding the notation used in Electromagnetism (E&M) classes, particularly the multiple variations of the letter "r." Participants express frustration over having to track numerous forms of "r," including capital and lowercase versions, as well as different notations like "squiggle" r and r hats. The complexity is exacerbated by the use of various indices and symbols from different alphabets, which can lead to misunderstandings. Suggestions include relabeling variables to more intuitive names to ease comprehension. Overall, the consensus is that the notation system in E&M is overly complicated and could benefit from simplification.
leroyjenkens
Messages
615
Reaction score
49
I just started an E&M class and right from the beginning the notation seems so confusing it has to have been done as a joke.
Trying to do a problem I run into about 10 different r's I have to keep track of.
Capital R
Lower case r
Lower case r prime
The r in spherical coordinates
The "squiggle" r (As this professor calls it. Never heard that before this class, but he talked about it like everyone knows. It's just a cursive r from what I can tell.)
"Squiggle" r hat
Normal r hat prime
"Squiggle" r with an arrow over it.
The normal r with an arrow over it
Normal r with an arrow over it prime

So when I see an equation with 3 or 4 different r's in it, my head just explodes. Why is it like this? And am I the only one who thinks this makes it confusing?
 
Physics news on Phys.org
This is what happens when you restrict yourself to the latin Alphabet. Try using Greek and Cyrillic letters if you run out.
 
There is a weird fascination with symmetry and making letters look the same. Euler angles were introduced to me with \xi, \zeta, \eta as indices. Integration by parts uses u and v, there is p and q for Lagrange mechanics. i and j for electrodynamics. {j,k,l} and {x,y,z} might not be so bad, but j and l are close in some handwriting as well as x and y. These things will never be reformed because we are still citing papers from 1910. The worst we had was in the discussion of collisions where I think r-prime-prime-tilda-hat was the vector of the second particle after the collision in center of mass coordinates.
 
I find it works extremely well when dealing with an unfamiliar notion to relabel each variable to something that makes sense to you, like m_{electron} instead of Z_0 for example. Then rewrite all of the equations and work with them until you feel comfortable and translate back as required.
 
In sci-fi when an author is talking about space travellers or describing the movement of galaxies they will say something like “movement in space only means anything in relation to another object”. Examples of this would be, a space ship moving away from earth at 100 km/s, or 2 galaxies moving towards each other at one light year per century. I think it would make it easier to describe movement in space if we had three axis that we all agree on and we used 0 km/s relative to the speed of...

Similar threads

  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
912
  • · Replies 4 ·
Replies
4
Views
1K