Optics basics: reflection

It’s been some 5 years since I wrote my last “Optics basics” post!  The goal of that series of posts was to introduce some of the most fundamental concepts in optics in a non-technical way, in part so I wouldn’t have to constantly reexplain them in more advanced posts.

I’ve covered most of the topics that I would truly call “basic” — hence the long time since the last post — but I realized that I missed one concept that...

Pepper’s last optical illusion: metempsychosis

A month ago, I shared the lengthy, odd and sometimes dramatic history of the illusion commonly known as “Pepper’s ghost,” which I believe is more properly called the “Pepper-Dircks ghost.”  In researching this post, I uncovered a wealth of fascinating information and trivia related to Pepper, Dircks, and their work, which continues to serve as fodder for posts.

For instance: “the ghost” is not the only optical illusion that...

Twitter Weird Science Facts: Full Year and Final Volume!

This is it — the last regular installment of my Twitter weird science facts! I’ve done a full year of weirdscifacts, averaging one fact per day for the entire year (though I’ve had to play catch up on missed days quite often).  It’s quite a lot of work to find and post reliable facts every day, even with the amount I’ve got backed up, so I won’t be continuing the series at this time.  You can always read the whole series of this year, and past...

Isaac Asimov’s Foundation Trilogy

I’ve recently been trying to become more acquainted with science fiction as a genre, as most of my life I’ve been focused primarily on horror fiction.  A natural and obvious place to place some emphasis is on classic works from the golden age of science fiction, and a natural and obvious place to start there is with the work of Isaac Asimov.  A few weeks ago, I read Asimov’s Foundation (1951), and blogged my thoughts about it.

Asimov has written seven books...

Michael Faraday meets “The Ghost”

My most recent blog post, concerning the history of the Pepper-Dircks Ghost, was extremely long but didn’t even include all the fascinating aspects of its history.  For instance: the ghost was such an incredibly effective illusion that it even drew celebrities of all types to see it.  From Pepper’s own True History, for example, we have the following description from the May 20th, 1863 edition of The Times:

Yesterday morning, by special command. Professor...

The Left Hand of Darkness, by Ursula K. Le Guin

After reading the epic Foundation series of novels by Asimov, I was in the mood for a change of pace in science fiction.  I turned to another brilliant author, Ursula K. Le Guin, and her classic 1969 novel The Left Hand of Darkness.

I vaguely remember being told about this novel when I was in college, though I didn’t read it then. At the time, the description that I was given was more or less “a book entirely about linguistic, social and cultural details.”  ...

Foundation’s Edge, Foundation and Earth, by Isaac Asimov

Been rather preoccupied recently with life, but I finally have a moment to catch up on a bit of my book blogging, including discussing the “final” two books of Asimov’s classic Foundation series, namely, Foundation’s Edge (1982) and Foundation and Earth (1986).  I have previously written about the first book Foundation as well as the complete trilogy of books, finished in 1953.

I wrote “final” in quote above because, although these...

19th century optics FAILs

My recent post on the Pepper-Dircks ghost didn’t include even close to all of the interesting tidbits it could have!  There are so many things to learn from the story of the ghost, including some lessons about optics.

For example: in my post, I included two illustrations of the illusion at work from sources of that era.  One came from the 1868 book The World of Wonders

Pepper’s illusion in action, from The World of Wonders (1868).

… and the other came...

Twitter Weird Science Facts, Volume 19

Happy Holidays!  Nearing completion of a full year of facts!  Read on to learn what this strange leech-based device was designed to do.

341. (December 7). Starfish Prime, a 1962 space nuclear test, blew out power lines & lights 900 km away in Hawaii! This test was done, in essence, simply to see what would happen!  We learned some good science from it, though that was not really the military’s goal.

342. (December 8). Sigmund Freud — proponent of cocaine!...

Dircks and Pepper: A Tale of Two Ghosts

It is often told that in the 1860s, John Henry Pepper used science and technology to invent a ghost.

Or did he?

This is the surprisingly tricky question that we will try to answer in this lengthy post.

It is a somewhat sad and recurring theme in science that many discoveries are not named after the actual people that discovered them.  In fact, this phenomenon is so common that it has a name — Stigler’s law.  Appropriately, Stigler’s law was, in fact, first...

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