Site Updates |

24 March 2018 -- Added the circular
versus hyperbolic functions page. Not deep but it was
entertaining to write. |

One little wrong turn in the
derivation... |

1/25/09 -- Added some comments on what changed to the oil price model page.

1/21/09 -- Added discussion of half-lenses and ideal scaling lenses to the tiny lenses page.

1/18/09 -- Added the Tiny Lenses page and moved some material over to it from Spherical Lenses, then added the section on off-axis behavior of tiny lenses.

1/15/09 -- Added several pages to the Simple Optics section: added Snell's Law, Ideal Lenses part II, Diopters, and Spherical Lenses pages. Still need to correct some things in the rest of that section -- doing the new pages was educational.

4/25/08 -- Added Oil Price Model page, in the misc section

2/26/08 -- Added Volume of a Sphere page, in the basic math and physics section

2/20/08 -- Added Pi page to the basic math and physics section

2/16/08 -- Added Aha! Proof version 2 to the proof by picture section.

2/15/08 -- Added Stars in Apollo Photographs page to the misc section. (Page has actually been on the site for a few days but had not been previously linked to.)

2/14/08 -- Added PoincarĂ© 1900 translation, in the misc section

1/20/08 -- Added the rust page

11/23/07 -- Added the cardinality page to the numbers section

11/19/07 -- Added the numbers section, which is still rather incomplete. The basics are there, but a number of theorems are missing, there are no explanatory notes on the notation, and the commentary on cardinality hasn' t been written yet.

11/04/07 -- Added the calculus section, which is still very incomplete -- about half of the planned pages are present. Creating the illustrations has proven to be time consuming.

9/26/07 -- Updated simple optics section. Added proof that simple systems of lenses and mirrors can't enhance visual image brightness.

9/23/07 -- Added simple optics section. Still incomplete, but the main proof is taking a while and I wanted to get the rest up in the mean time. Also added solid angles page, which was needed by the optics pages.

9/7/07 -- Added casual interference patterns page

2/7/07 -- Added speed of light page

2/5/07 -- Added speed of sound page

1/17/07 -- Added moving charge page

1/8/07 -- Added magnetism index page along with two-charge dipoles and the derivation of the dipole field. Moved the dipole force page under magnetism.

12/22/06 -- Added permanent magnet motors and force on a dipole pages.

12/1/06 -- Updated Lagrangian page a bit, and added a few more simple examples.

11/24/06 -- Flipped sign of constant

11/20/06 -- Minor corrections to Lagrangians page, and added a few missing illustrations on the orbit shapes page.

11/18/06 -- Added the orbit shapes page, which still needs some pictures.

11/16/06 -- Reorganized the site, giving it a little more of a tree structure. It was becoming impossible to find anything and hard to see what was present.

11/15/06 -- Added a trivial proof that the hyperbolic angle is the area above the hyperbola. (Even the trivial ones take time, though, 'cause of the illustrations.)

11/13/06 -- Added the Lagrangian mechanics page.

11/10/06 -- Added the conic sections page, which probably shouldn't be on the front page. Oh, well, the whole site could use reorganizing ... someday.

11/7/06 -- Added the hyperbola focus page under proof-by-picture.

11/6/06 -- Added the ellipse focus page under proof-by-picture. I expect to add a handful of additional "elementary" items to the proof-by-picture page in the coming weeks.

11/2/06 -- Added the parabola focus page under proof-by-picture, and reorganized the proof-by-picture page a little.

10/31/06 -- Added the shortest path condition derivations, both visual and symbolic.

10/25/06 -- Added the Pythagoras page.

9/6/05 -- Added and then corrected the Swing page.

8/16/05 -- Added Alexander's horse.

8/15/05 -- Added SETI page, cleaned up equation formating on linear twins page.

8/9/05 -- Added the Horse of a Different Color.

8/8/05 -- Added Lorentz transform derivation page. Also updated my links page -- should do that more often; several of the links had gone bad or moved.

8/5/05 -- Rewrote comments regarding classical explanations of the Sagnac effect. The comments are on their own page.

7/25/05 -- Added a page on the Sagnac effect.

7/4/05 -- Corrections to French version of the CCentipede story, courtesy of Bernard Chaverondier; remaining errors on that page are entirely mine.

6/22/05 -- Translated the CCentipede story into French.

12/3/04 -- Rewrote the 1996 statistical analysis section on the Florida page. It was wrong.

12/2/04 -- Further updates to the Florida page, including a statistical analysis of 1996 data and a reanalysis of the 2000 and 2004 data. Gotta get back to adding physics and math items, one of these days...

11/8/04 -- Added "miscellaneous" page, and added Florida election data analysis under it.

8/23/04 -- Completed addition of covariant derivatives pages for vectors and 1-forms, under the proof-by-picture page. Could still use some work but it's a start.

8/13/04 -- Added a books page

8/11/04 -- Cleaned up the 1-form page a bit (flipped the diagrams, renamed dual vectors to covectors), added some terms to the glossary, and added the nascent "proof-by-picture" page to the table of contents.

8/9/04 -- Added a (very brief!) glossary, after some feedback indicating I left a lot of things undefined

7/15/2004 -- Corrected a minor error on Revolving Astronaut page and added an explanatory comment

7/10/2004 -- Added Superluminal Shells and Rigid Rods pages

5/27/2004 -- Added the Distant Revolving Astronaut

5/25/2004 -- Added porthole view from Earth and some graphs to "accelerating twins" page

5/19/2004 -- Added "accelerating twins" page, sans graphs and part of the porthole view section

5/8/2004 -- Site went "live"