A mnemonic is a device to aid the memory. Sometimes called a mnemonic device, it captures information in a memorable way to help a person remember something that is important. Students often use them to quickly recall information that is frequently used and needs to be at their fingertips, but they are also used to help jog the memory of less frequently used information, for example, to recall symptoms or procedures for rarely encountered situations. People may also use one to remember things on a single occasion, such as a shopping list.
The type of memory device used is important because different people find different kinds of information easier to remember. Some people find that a rhyme most easily sticks in the mind, while others find that an association that they make themselves is the best strategy. Other people use whatever has already been created for the particular bit of information that they are trying to remember. The key is for individuals to choose a type of mnemonic that works well for them.
Some of the main types are rhymes, acronyms, associations, and sentences. Some mnemonics, including several used for spelling, take the form of short rhymes. One helps a person remember the order of the letters i and e in a word:
I before e,
except after c
or when sounding like “a”
as in neighbor or weigh.
Another helps with the spelling of words with vowel digraphs in which the pronunciation matches the sound of one of the vowels, as in the word beat or the word main:
When two vowels go walking,
The first one does the talking.
Another type is formed like an acronym with each letter or number carrying a reminder of some specific information. The ABCDEs for a mole to determine whether it might be cancerous are an example:
In a number mnemonic, each number has a rhyme word, and the information that a person wants to remember is associated with the rhyme. The words are referred to as “peg words” because the items to be remembered is “pegged” to them. One popular system is set up like this:
A sentence mnemonic carries information in each word, in one way or another. Some examples focus on the number of letters in each word. This is true in the uncredited rhyme:
Sir, I send a rhyme excelling
In sacred truth and rigid spelling
Numerical sprites elucidate
For me the lexicon's dull weight.
In this rhyme, the number of letters in the carefully ordered sequence of words gives the first 20 digits of the value of pi.
In other examples, the focus is the first letter of each word, which is often a reminder of order, as in "Please Excuse My Dear Aunt Sally," which reminds people of the order of operations in solving a math problem: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction.
Another popular example, though out of date, given the demotion of Pluto from planet status, is "My Very Educated Mother Just Served Us Nine Pizzas" to help recall the order of the planets from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.