Earlier this week in the Book Nook section of our Educators page, we featured an excerpt from Nancy Frey and Douglas Fisher's Learning Words Inside and Out, all about how teachers can use mnemonics to help students commit words to memory. Some of these memory aids are extremely well-known: most everyone knows Roy G. Biv spells out the initial letters of the seven colors in the spectrum, for instance. But there's an endless number of other mnemonic devices that get passed down from generation to generation, covering just about every field of human endeavor.

Some mnemonics are simple rhymes, like "Thirty days hath September..." or "I before E, except after C..." Others are acronyms to help you remember the spelling of tricky words: if you have trouble spelling rhythm, just remember the first letters of Rhythm Helps Your Two Hips Move. There are also acronyms that expand to create a sentence encapsulating a rule; thus, OILRIG is a handy mnemonic in chemistry to remember that Oxidation Is Loss, Reduction Is Gain (meaning that oxidation results in the loss of electrons, while reduction results in the gain of electrons.)

Many mnemonic devices are acronyms to help you remember items on a list. When the list isn't in any set order, it allows for more freedom in creating a mnemonic: for instance, HOMES helps you remember the names of the Great Lakes, even though there's no signficance to the order of Huron, Ontario, Michigan, Erie, Superior. Most of these mnemonics, however, have a particular order to memorize, as in Roy G. Biv for the colors of the visible spectrum (red, orange, yellow, green, blue, indigo, violet). Who is Roy G. Biv, anyway? I've read that he's supposed to be a leprechaun who spells out the rainbow, but to me he sounds more like a mild-mannered accountant. I personally prefer reading the mnemonic the other way around, as Vibgyor, which you could imagine as the name of a rampaging warrior. VIBGYOR! (And sure enough, now that I look, a writer named Walter Herries Pollock wrote a story way back in 1874 featuring a cruel Prince Vibgyor.)

When the list doesn't lend itself to an acronymic reading, it can instead be treated as an acrostic, with the initial letters of the listed items corresponding to initial letters of words in a mnemonic phrase. Thus, instead of Roy G. Biv, you can use "Richard Of York Gave Battle In Vain." (That mnemonic has a bonus feature: it tells you who lost the Battle of Wakefield, waged in 1460 between the Houses of York and Lancaster in the Wars of the Roses.) The longer the order, the more involved the acrostic gets. Say you're hoping to commit to memory the order of geological time periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Recent. You're going to need something like, "Cows Often Sit Down Carefully. Perhaps Their Joints Creak? Persistent Early Oiling Might Prevent Painful Rheumatism." It's so long you might need a mnemonic for your mnemonic!

The order of the planets in the solar system is a classic list in need of a good mnemonic. Before the discovery of Pluto in 1930, a popular mnemonic was "Mary's Violet Eyes Made John Stay Up Nights" (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune). Then when Pluto was added to the roster, nine-planet mnemonics arose like "My Very Excellent (or Educated, or Extravagant, or Energetic) Mother Just Sent Us Nine Pizzas (or Parrots, or Pickles, or Pies)." After Pluto was heartlessly demoted from planethood in 2006, science educators had to get rid of the "Pizzas," instead opting for mnemonics like "My Very Excellent Mother Just Sent Us Noodles." In the Pluto-less lineup, I'd recommend going back to the "Mary's Violet Eyes" golden oldie, which has a wistful, haunting quality to it.

What's your favorite mnemonic? Have you created any yourself? Let us know in the comments below! I'll start the ball rolling with one that I made in high school biology class to memorize the stages of fetal development (zygote, blastula, gastrula, embryo, fetus): "Zbigniew Brzezinski Goosed Ella Fitzgerald." I thought I was terribly clever, though my classmates didn't seem to think so. Still, I know I'm going to remember that mnemonic to my dying day.