Mnemonics

This is a collection of some mnemonics that I discovered on the internet or have come up with myself. I only use a portion of these right now—some are classics whereas others are included for completeness.

Mnemonics that I've shared on the weblog:

• Mnemonic for US states

Major system

[Wikipedia]

The consonant sounds of h, w, and y can be added freely since they don’t appear on the list. For example, 32 can become man, human, woman, or Yemen.

Morse code

[Wikipedia, Vsauce video]

Numerals

Alphabets

Note: In word mnemonics, short letters (aceimnorsuvwxz) correspond to a dot and tall letters (bdfghjklpqty) or uppercase letters correspond to a dash. These are taken from Douglas Harder.

*: Tall letters with morse code starting with a dot.

Characters

CS and Programming

• OSI Network Layer model (Physical, Datalink, Network, Transport, Session, Presentation, Application):

  Please Do Not Throw Sausage Pizza Away
  Please Do Not Teach Students Pointless Acronyms

• CSS margin: TRouBLe (Top Right Bottom Left)

  .class {
    margin: T R B L 
  }
  

Math

• Order of Operations (Parenthesis, Exponents, Multiplication and Division, Addition and Subtraction):

  PEMDAS

• Euler's characteristic (X = F + V - E):

  fav.me (F add V, minus E)

• Trigonometric ratios (Sine = Opposite / Hypotenuse, Cosine = Adjacent / Hypotenuse, Tangent = Opposite / Adjacent):

  SOH CAH TOA

• Determining which functions are to be chosen as u and DV in integration by parts (Logarithmic, Inverse trigonometric, Algebraic, Trigonometric, Exponential):

  LIATE

• Sign of each trigonometric functions in each quadrant of the plane: All Students Take Calculus or ASTC

  • Quadrant I: All trigonometric functions are positive.
  • Quadrant II: Sine and cosecant functions are positive.
  • Quadrant III: Tangent and cotangent functions are positive.
  • Quadrant IV: Cosine and secant functions are positive.

• e (2.718281828459045)

  • Andrew Jackson was the 7th president of the US: 7
  • He was elected in 1828 and served two terms: 1828 1828
  • His favorite type of triangle was the right angled isosceles triangle: 45 90 45

Science

• Order of planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto):

  My Very Easy Method Just Speeds Up Naming Planets
  For eight planets: My Very Easy Memory Jingle Seems Useless Now

• Colors of rainbow (Red, Orange, Yellow, Green, Blue, Indigo, Violet):

  ROYGBIV (VIBGYOR in reverse)

• Layers of atmosphere (Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere):

  The Strong Man's Triceps Exploded
  The Sick Man's Thermometer Exploded

• Diatomic elements (Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, Fluorine):

  BrINClHOF (pronounced 'brinkelhoff')

• PANIC: Positive Anode Negative Is Cathode.

• LEO the lion says GER: Loss of Electrons, Oxidation; Gain of Electrons, Reduction

• AN OIL CAT RIG

  At the ANode, Oxidation Involves electron Loss.
  At the CAThode, Reduction Involves electron Gain.

• Speed of light (299,792,458):

  nabob cabin relief (Major system)
  We guarantee certainty, clearly referring to this light mnemonic (Counting the number of letters in each word)

• Increasing frequency or decreasing wavelength of electromagnetic waves (Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-Rays, Gamma Rays):

  Rich Men In Vegas Use eXpensive Gadgets
  Opposite order: Good Xylophones Use Very Interesting Musical Rhythms

• Order of taxa in biology (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, [Variety]):

  Dear King Philip Came Over For Good Soup.

• Resistor color codes: Better Be Right Or Your Great Big Vacation Goes Wrong

  • 0 = Black
  • 1 = Brown
  • 2 = Red
  • 3 = Orange
  • 4 = Yellow
  • 5 = Green
  • 6 = Blue
  • 7 = Violet
  • 8 = Gray
  • 9 = White

• Differentiating stalactites from stalagmites:

  The 'mites go up and the 'tites come down

• 10 organ systems of the human body (Nervous, Integumentary, Circulatory, Endocrine, Respiratory, Digestive, Reproductive, Urinary, Muscular, Skeletal):

  NICER DRUMS

Geography

• The Great Lakes in order of largest to smallest (Superior, Huron, Michigan, Erie, Ontario):

  Super Heroes Must Eat Oats (or SHMEO)

• Major cities of Australia (clockwise): BSC MAPD H:

  Brisbane, Sydney, Canberra, Melbourne, Adelaide, Perth, Darwin, Hobart

Chess

• Setting up a chess board (Bottom right corner for both players must be a light square):

  White on the right

• Philidor vs Lucena:

  Philidor position is a drawing technique. Both words have a "d" (for draw).
  Lucena is a winning position. Neither word has a "d".

Number of days in each month

It's easy to remember that February has 28 days in a common year, and 29 days in a leap year, which occurs every four years (except for century years not divisible by 400).

To remember that April, June, September, and November have 30 days, use any of the following mnemonics. All the rest have 31 days.

• The one I use, which I came up with in middle school: SNAp June

• The one that I taught my 5yo nephew: ape-jun-se-no

• Numeric: 4 6 9/11

• In Roman numerals: IV/VI IX/XI (each contains exactly two unique letters and each pair is a mirror of the other)

• Knuckle mnemonic

• Thirty Days Hath September

  Thirty days has September,
  April, June, and November,
  All the rest have thirty-one,
  Save February at twenty-eight,
  But leap year, coming once in four,
  February then has one day more.
  

Misc

• Confronting a screw:

  Righty-tighty, Lefty-loosy or Right on, Left off

• Identifying coral snakes:

  Red touches yellow, kills a fellow. Red touches black, friend of Jack.

• The first 11 (and most important) Ionian philosophers (Thales, Heraclitus, Empedocles, Leucippus, Anaximander, Democritus, Zeno, Anaximenes, Protagoras, Parmenides, Anaxagoras):

  THE LAD ZAPPA

• Daylight savings time:

  spring forward, fall back

Links

• List of mnemonics