Mnemonic Devices in Science

Many people employ mnemonic devices to remember things. Mnemonic devices are techniques that are used to make it easier to memorize and recall information. For example, when I was in high school, we were trying to remember the names of the Great Lakes for our geography class. The professor asked if anyone’s name begun with an “e”. Promptly a girl named Ester raised her hand. The professor then told us to remember the phrase “Only Ester Has Much Sense” because the first letters stood for the name of the Great Lakes (Ontario, Erie, Huron, Michigan, and Superior).
 
In many disciplines of human knowledge generations of students have used these mnemonic devices, and science is no exception. Many mnemonics are outrageous, silly, or naughty on purpose to maximize the memory process, while others are quite bland. Today we shall take a look at several of the most interesting mnemonic devices used in the sciences.
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Chemistry
 
In the chemical sciences, students and researchers often have to dilute strong acids with water to prepare solutions. But this process carries a dangerous pitfall. When water is added to a strong acid, a vigorous reaction occurs that releases heat and quickly converts the water to gas. This can make the acid splash with dangerous consequences. Interestingly, the reaction obtained when doing the opposite, adding the strong acid to water, is not as strong. Therefore chemistry students are taught the mnemonic rule: “Do like you ought’er, add acid to water”. This is often changed to the more humorous expression, “Do like you otter, add acid to water”.
 
In electrochemistry, the process by which an element loses (oxidation) or gains (reduction) electrons and where this takes place (anode or cathode), can be remembered by the mnemonic Red Cat (Reduction at Cathode) and An Ox (Anode for Oxidation).
 
The most prolific area for mnemonic devices in chemistry is that devoted to remembering the elements of the periodic table and their order. An example covering the first 18 elements is Here He Lies Beneath Bed Clothes, Nothing On, Feeling Nervous. Naughty Margaret Always Sighs, "Please Stop Clowning Around." This corresponds to Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluoride, Neon, Natrium (sodium), Magnessium, Aluminum, Silicon, Phosphorous, Sulphur, Chloride, and Argon.
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​Medicine
 
The field of medicine boasts a huge list of mnemonic devices as medical students have to memorize a prodigious amount of names corresponding to things ranging from structures in the human body to the symptoms of diseases or conditions.
 
One example is Some Lovers Try Positions That They Can't Handle, which is the mnemonic to remember the names of the bones of the wrist: Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, and Hamate. Another is Old People From Texas Eat Spiders, which is the mnemonic to remember the bones of the skull: Occipital, Parietal, Frontal, Temporal, Ethnoid, and Sphenoid.
 
Some medical mnemonic devices are not that elaborate. An example is the possible causes of abdominal swelling which is coded in “The 9 F’s”: Fat, Feces, Fluid, Flatus, Fetus, Full-sized tumors, Full bladder, Fibroids, and False pregnancy.
 
A few medical mnemonics are even funny in a dark humor sort of way. The primary causes of urinary incontinence, Delirium, Infection, Atrophic vaginitis, Pharmaceuticals, Excess excretion, Restricted mobility, and Stool impaction, are remembered by the mnemonic DIAPERS. The activities that an individual needs to perform in order to function independently, Dressing, Eating, Ambulation, Toileting, and Hygiene, are remembered by employing the mnemonic DEATH.
 
Astronomy
 
Students of astronomy have to memorize the names of many celestial bodies and systems of classification.
 
The name and order of the planets in the solar system could be memorized using My Very Educated Mother Just Served Us Nine Pizzas, which of course refers to Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. This was at least during the time Pluto was considered a bona fide planet. Now, that the official planets in the solar system stop at Neptune, the very educated mother probably Just Served Us Noodles.
 
A particular mnemonic famous in the astronomical community is that for remembering the spectral classification of stars. Depending on the spectrum of the light emitted by stars, they are classified as O, B, A, F, G, K. and M. The mnemonic traditionally used to remember this is Oh, Be A Fine Girl Kiss Me. Since the mnemonic was coined, not only have new categories been created in the classification, but also efforts have been made to make the mnemonic less sexist (for example: Only Boys Accepting Feminism Get Kissed Meaningfully). There are many alternative versions of this mnemonic.
 
Biology
 
Living things and their complexity have given rise to many names that biology students must remember.
 
For example, in biology the levels of classification of living things, Kingdom, Phylum, Class, Order, Family, Genus, Species, can be remembered by the mnemonic King Phillip Came Over From Germany Stoned, or many of its watered down versions to avoid the reference to intoxicating substances.
 
In cell biology the different stages of the cell cycle are remembered through mnemonics such as Idiot, Pass Me Another Tequila, which corresponds to the phases of mitosis (Interphase, Prophase, Metaphase, Anaphase, and Telophase), or “the cat Peed on a MAT”, which corresponds to the phases of meiosis (Prophase, Metaphase, Anaphase, Telophase).
 
Mathematics
 
In math, mnemonics are used to remember formulas and solutions to different equations. One particular example is from the area of trigonometry where the value of the sine, cosine, and tangent of an angle of a right-angled triangle can be derived from mathematical equations performed on the length of the sides of the triangle. The formulas can be remembered using the mnemonic Some Old Hippie, Caught Another Hippie, Tripping On Acid.
 
Sine = Opposite side ÷ Hypotenuse (Some Old Hippie)
Cosine = Adjacent side ÷ Hypotenuse (Caught Another Hippie)
Tangent = Opposite side ÷ Adjacent side (Tripping On Acid)
 
Geology
 
The geology fact that most people wish to remember concerns the orientation of stalactites and stalagmites. Many geology students remember this by using a mnemonic that envisions someone wearing tights being accosted by an army of mites crawling up their legs, thus: When the mites go up, the tites (tights) come down.
 
But hardcore geology students have to memorize many complex names regarding rocks, their properties, and the different geologic times. For example, Pregnant Cows Often Sit Down Carefully. Perhaps Their Joints Creak. Possibly Early Oiling Might Prevent Premature Rheumatism. This mnemonic stands for the geological time periods: Precambrian, Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurrasic, Cretaceous, Pliocene, Eocene, Oligocene, Myocene, Pileocene, Pleistocene, and Recent (Holocene).
 
I could go on, but you get the idea of the richness and ingenuity of science students trying to remember the vast amounts of information that is necessary to succeed in their fields. Do you have a favorite mnemonic? Please share it here by leaving a comment.

Otter picture modified from the original, by Marshal Hedin and used here under an Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license.