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Mnemonic trick for converting between Fahrenheit and Celsius

9 Jan

From the always interesting Benny Lewis:

Eponyms as mnemonics

10 Aug

Did you know that Melba toast was named after Dame Nellie Melba of that the word “nicotine” honors Jean Nicot de Villemain? These examples are from Alex Novak’s book Tawdry Knickers and Other Unfortunate Ways to Be Remembered: A Saucy and Spirited History of Ninety Notorious Namesakes

Eponyms can be powerful mnemonics and you can find a long list of them here.

Dewey Decimal System Mnemonic

1 Aug

Here is a first letter mnemonic for the potentially useful task of learning the Dewey Decimal System:

Generally, philosophical religionists see language scientifically to favor literary history.

Category Catalog Number Mnemonic
General Works 0 Generally
Philosophy and psychology 100 philosophical
religion 200 religionists
Social Science 300 see
Language 400 language
Science 500 scientifically
Technology 600 to
Fine arts 700 favor
Literature 800 literary
History 900 history

Adapted from Evans (2007)

How to remember KIC 8462852

26 Oct

I am fascinated by the very remote possibility that observations of the star KIC 8462852 may be evidence for an extra-terrestrial civilization.

I don’t have the competence to evaluate or comment on the evidence. What I can do is help you to commit the name “KIC 8462852” to memory.

First, you need to know the Dominic System and the Peg System,  they will take you only a few minutes to learn and its worth effort.

KIC stands for Kepler Input Catalog, but it might help to remember it as Kentucky Intergalactic Chicken (perhaps what they serve at the Star Wars bar).


Now, in the Domonic System 84 translates to HD – think Humpty Dumpty


62 is SB or Sleeping Beauty


85 is HE, why not Happy Easter?


Now we have one more digit 2 so lets use the Peg System and represent it as a shoe.


So just think of Humpty Dumpty, Sleeping Beauty, celebrating a happy Easter all nestled inside a shoe. The more ridiculous and vivid you can make the image the easier it will be to remember.

Now you’ll sound really smart.

How to memorize a formula

18 Sep

Yesterday, I blogged about a mnemonic for learning the quadratic equation. Here is an excellent video that teaches a general mnemonic technique for formula memorization:



Quadratic formula mnemonic

17 Sep


Going through some of my notes I rediscovered this mnemonic for the quadratic formula:

From square of b, take 4ac;
Square root extract, and b subtract;
Divide by 2a; you’ve x, hooray!

I am not sure of the origins of this mnemonic. The earliest version I could find was from J. S. Mackay in 1894, but he says the mnemonic was given to him by a member of the Edinburgh Mathematical Society.

Here’s another mnemonic for the quadratic formula:




And let’s not forget the Quadratic Formula Rap:


The number peg memory system

28 Aug

In the peg method, sometimes called the minor peg system, an individual memorizes a fixed set of ordered mnemonic cues. It can be used to learn ordered and unordered lists, such as a set of historical events or your weekly shopping. The technique relies on the use of vivid visual images.

The most widely used peg system is the number peg method. This system invented by John Sambrook in 1889 and a simplified version is described in most books on memory improvement. The peg word system is easy to learn and can supplement other mnemonic devices that we will be learning, such as the Dominic system. The first step is to create a numbered list of ten mnemonics pegs. Each peg word should rhymes with its respective number making the list easier to learn. Here is a suggested list, but you should modify if you can think of words that are more memorable to you. For example if the word “bricks” is easier for you to visualize than the word “sticks,” by all means, use it as your peg word for number six.

Number Peg Word
1               Gun
2               Shoe
3               Tree
4               Door
5               Hive
6               Sticks
7              Heaven
8              Gate
9             Vine
10           Hen

Once you have committed the list to memory, you are now ready to try to learn a list. What you will do is to make a vivid visual association with each item.

So let’s try to learn a grocery list. Suppose you want to purchase the following ten items; 1. oatmeal, 2. apples, 3. bananas, 4. spaghetti, 5. peanut butter, 6. carrots, 7. mushrooms, 8. maple syrup, 9. baked beans, 10. soy milk. Here is a chart suggesting visual associations between the items and the peg words.


Peg Word






Gun shooting out oatmeal (instead of bullets)




Shoe crushing apples under its heel




A tree with bananas hanging on it




Spaghetti forcing itself through a door



peanut butter

Bee hive made of peanut butter




A bundle of carrots wrapped up like sticks




Giant mushrooms growing in heaven



Maple syrup

A gate holding back a flood of maple syrup



Baked Beans

Cans of baked beans growing on a vine



Soy milk

A hen laying a carton of soy milk

If some of these associations seem bizarre, so much the better. The more bizarre, the easier to remember, a phenomenon called the bizarreness effect. It is important to try to create vivid visual images for each association. If, in addition you can link the image to something you already know the easier it will be to remember. For example, when I think of a gate holding back a flood of maple syrup, I am reminded of the Boston Molasses Disaster of 1919

When one reuses the same pegs over and over again there is always some danger that memorizing one list might interfere with the learning of a later list. However, research suggests that the number peg system can used over and over again.

Here is a video showing a version of the number peg system:

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