| Topic: |
Science > Physics |
| User: |
"Hasan Karabulut" |
| Date: |
07 Jan 2005 10:11:14 AM |
| Object: |
Units, dimensions, dimensional analysis |
Hi there everbody,
I teach undergraduate physics courses and our students are exposed to
both CI and CGS unit in electricity and Magnetism courses. In Atomic
and molecular physics course I teach them atomic units (h_bar=1,
4*pi*epsilon_sub{zero}=1, bohr radius=1, electrons charge=1.) I am
also aware that there are other units used in high energy physics
where it is advantageous to take c=1 and there are many other unit
systems used in electromagnetism in the past. In SI there are three
dimensions(mass, lenght and time) and in SI there are four
dimensions(charge is a separate dimension) and this confuses students.
Besides the issue of units, there is also a whole field of
dimensional analysis. In engineering courses they teach students pi
theorem, how to make equations dimensionless, and how to define and
take advantage of dimensionless numbers in heat and mass transfer
theory. Dimensional analysis is not a part of physics curriculum
here.
After giving it some thought I decided that I should do something
about this. I intend to provide students with an approximately 100-150
pages handout discussing the entire philosophy behind dimensions,
units, different unit systems, the dimensionless analysis and all
that. I could not find any suitable text that does this in our
library. I do not feel competent to write it myself at this point. I
may attempt to write it myself (after doing some research on it) if I
do not find an adequate book or lecture notes.
Can anybody out there help me find useful documents on units,
dimensions and dimensional analysis?
.
|
|
| User: "Franz Heymann" |
|
| Title: Re: Units, dimensions, dimensional analysis |
07 Jan 2005 11:59:46 PM |
|
|
"Hasan Karabulut" <mathfan@mynet.com> wrote in message
news:f195738f.0501070811.3cca7c21@posting.google.com...
Hi there everbody,
I teach undergraduate physics courses and our students are exposed
to
both CI and CGS unit in electricity and Magnetism courses. In Atomic
and molecular physics course I teach them atomic units (h_bar=1,
4*pi*epsilon_sub{zero}=1, bohr radius=1, electrons charge=1.) I am
also aware that there are other units used in high energy physics
where it is advantageous to take c=1 and there are many other unit
systems used in electromagnetism in the past. In SI there are three
dimensions(mass, lenght and time) and in SI there are four
dimensions(charge is a separate dimension) and this confuses
students.
Yes, indeed. The SI are a horribly cobbled-together set of units.
[snip]
Franz
.
|
|
|
|
| User: "FrediFizzx" |
|
| Title: Re: Units, dimensions, dimensional analysis |
07 Jan 2005 01:26:55 PM |
|
|
"Hasan Karabulut" <mathfan@mynet.com> wrote in message
news:f195738f.0501070811.3cca7c21@posting.google.com...
| Hi there everbody,
|
| I teach undergraduate physics courses and our students are exposed to
| both CI and CGS unit in electricity and Magnetism courses. In Atomic
| and molecular physics course I teach them atomic units (h_bar=1,
| 4*pi*epsilon_sub{zero}=1, bohr radius=1, electrons charge=1.) I am
| also aware that there are other units used in high energy physics
| where it is advantageous to take c=1 and there are many other unit
| systems used in electromagnetism in the past. In SI there are three
| dimensions(mass, lenght and time) and in SI there are four
| dimensions(charge is a separate dimension) and this confuses students.
No wonder they are confused. ;-) In CGS units there are three dimensions.
In SI, it is current that is a base dimension. Not charge.
| Besides the issue of units, there is also a whole field of
| dimensional analysis. In engineering courses they teach students pi
| theorem, how to make equations dimensionless, and how to define and
| take advantage of dimensionless numbers in heat and mass transfer
| theory. Dimensional analysis is not a part of physics curriculum
| here.
|
| After giving it some thought I decided that I should do something
| about this. I intend to provide students with an approximately 100-150
| pages handout discussing the entire philosophy behind dimensions,
| units, different unit systems, the dimensionless analysis and all
| that. I could not find any suitable text that does this in our
| library. I do not feel competent to write it myself at this point. I
| may attempt to write it myself (after doing some research on it) if I
| do not find an adequate book or lecture notes.
|
| Can anybody out there help me find useful documents on units,
| dimensions and dimensional analysis?
Try these,
http://www.ee.surrey.ac.uk/Workshop/advice/coils/unit_systems/index.html
http://www.planck.com/unitsindex.htm
FrediFizzx
.
|
|
|
|
| User: "John T Lowry" |
|
| Title: Re: Units, dimensions, dimensional analysis |
07 Jan 2005 12:46:14 PM |
|
|
"Hasan Karabulut" <mathfan@mynet.com> wrote in message
news:f195738f.0501070811.3cca7c21@posting.google.com...
Hi there everbody,
I teach undergraduate physics courses and our students are exposed to
both CI and CGS unit in electricity and Magnetism courses. In Atomic
and molecular physics course I teach them atomic units (h_bar=1,
4*pi*epsilon_sub{zero}=1, bohr radius=1, electrons charge=1.) I am
also aware that there are other units used in high energy physics
where it is advantageous to take c=1 and there are many other unit
systems used in electromagnetism in the past. In SI there are three
dimensions(mass, lenght and time) and in SI there are four
dimensions(charge is a separate dimension) and this confuses students.
Besides the issue of units, there is also a whole field of
dimensional analysis. In engineering courses they teach students pi
theorem, how to make equations dimensionless, and how to define and
take advantage of dimensionless numbers in heat and mass transfer
theory. Dimensional analysis is not a part of physics curriculum
here.
After giving it some thought I decided that I should do something
about this. I intend to provide students with an approximately 100-150
pages handout discussing the entire philosophy behind dimensions,
units, different unit systems, the dimensionless analysis and all
that. I could not find any suitable text that does this in our
library. I do not feel competent to write it myself at this point. I
may attempt to write it myself (after doing some research on it) if I
do not find an adequate book or lecture notes.
Can anybody out there help me find useful documents on units,
dimensions and dimensional analysis?
There's a fairly dense text translated from the Russian, by Shirkov (?).
For elementary purposes, On Size and Life, by MacMahon and Bonner is
excellent. For derivations of the basic idea, see p. 37 of Bender's An
Introduction to Mathematical Modeling, a Dover book. The best I've seen
on that subject is a paper, "Buckingham's pi-theorem," by Harald
Hanche-Olsen, hanche@math.ntnu.no; he's in Norway but the paper's in
English. There are a few typos.
John Lowry, PhD
Flight Physics
.
|
|
|
|
| User: "Morituri-|-Max" |
|
| Title: Re: Units, dimensions, dimensional analysis |
07 Jan 2005 12:30:33 PM |
|
|
Hasan Karabulut wrote:
systems used in electromagnetism in the past. In SI there are three
dimensions(mass, lenght and time) and in SI there are four
dimensions(charge is a separate dimension) and this confuses students.
Why does it confuse them?
.
|
|
|
|
| User: "Guy Gordon" |
|
| Title: Re: Units, dimensions, dimensional analysis |
08 Jan 2005 01:36:15 AM |
|
|
There was a wonderful article titled "Dimensions Anyone?" in Analog SF magazine
in the late 60's, by John D. Clark, Ph.D. It's about at the level of a
Scientific American article, about 12 pages long.
I still have a copy.
Email me if you want a scan of it.
gordon "at" white-crane.com
.
|
|
|
|
|
Related Articles |
|
|
