1. The five Great Lakes: Huron, Ontario, Michigan, Erie, Superior.
2. The colors of the rainbow, in order: Red, Orange, Yellow, Green, Blue, Indigo, Violet.
3. This fictitious disk jockeyâ€™s business card gives you the months of the year, in sequential order: June, July, August, September, October, November, December, January, February, March, April, May.
4. For beginning French students, â€śone eggâ€ť is un oeuf. There are many mnemonics for words in almost every language. Other French ones: â€śPart II [partout] is everywhere,â€ť and â€śPluto [plutĂ´t] is coming soon.â€ť For Hebrew pronouns: â€śMe is who, who is he, and he is sheâ€ť (that is, mi means â€śwho,â€ť hu means â€śhe,â€ť and hi means â€śsheâ€ť). But in Japanese, mi = 3, hu = 2, hi = 1 and (in a different numeral sequence) shi = 4.
5. In music, the five lines on the treble clef are e, g, b, d, f, as in Every good boy does fine. The spaces are f, a, c, e, or face. For the lines on the bass clef, use â€śGood boys do fine alwaysâ€ť (g, b, d, f, a), where the spaces are remembered by All cows eat grass (a, c, e, g).
6. The spectral types of â€śmain sequenceâ€ť stars, starting with the hottest and brightest: O, B, A, F, G, K, M. (Our own yellow sun is merely around G7.)
7. The hierarchy of biological classification levels: Kingdom, Phylum, Class, Order, Family, Genus, Species. (Kingdoms are now grouped in larger units, the Eukaryotes, Prokaryotes, and Archaebacteria, which I have proposed should be called â€śEmpiresâ€ť; at the other end, Species are subdivided into â€śVarieties.â€ť A nine-word mnemonic can be coined to include these extensions: â€śEvery keen person can obtain fresh green salad veggies.â€ť
8. The color code on the stripes circling electrical resisters, for the digits 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, are (in order): black, brown, red, orange, yellow, green, blue, violet, gray, white. (Note the omission of â€śindigoâ€ť from A.2. above.)
9. The 12 pairs of cranial nerves, which every student of human anatomy must memorize, in order are: olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, acoustic, glossopharangeal, vagus, (spinal) accessory, hypoglossal. A companion mnemonic, to remember which nerves are sensory nerves, or motor nerves, or both, in the same order is: Some say â€śmarry money,â€ť but my brother says, â€śBad business marry money.â€ť
10. The successive digits of â€śpi,â€ť the ratio of the circumference to the diameter of a circle, are given by the number of letters in the words of this mnemonic: â€ś3.14159265358979.â€ť There are many other mnemonics for pi, both shorter and longer, and in many different languages. A short one, for 3.1416, is â€śNow I have a number.â€ť
1. â€śSpring forward, fall back.â€ť
2. â€śLefty loosy, righty tighty,â€ť or simply â€śClockwise to close.â€ť This works for screws, garden hose taps, and most other valves, but natural gas valves operate in the reverse direction!
3. â€śThirty days hath September,Â April, June, and November.Â All the rest have thirty-one.Â Save February, all alone,
Whose days are only eight and score, But leap year brings it one day more.â€ť
4. â€śI before E except after C,
Unless pronounced A, as in neighbor and weigh.â€ť
While this rule works for believe and receive, it has dozens of exceptions. (What general principle can explain siege vs. seize?) Today, instead of a mnemonic, one can use spell-check!
For bawdier mnemonics, e.g., for A.8 or A.9, ask someone who studied electrical engineering or pre-med anatomy, respectively.