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For people, place, prosperity and planet, we deliver impact with measurement science

SI Prefix mnemonic challenge

This challenge is now closed – check out our winners below!

To celebrate the recent expansion to the range of SI prefixes, (for the first time in 31 years!) we challenged primary and secondary school pupils to come up with two mnemonics (how to create a mnemonic) to help remember the names of all the SI prefixes. 

We are pleased to announce our winners as:

Primary School category: Alice from Twickenham Preparatory School

Large range: Dogs hate kissing monkeys given that primates eat zesty yuzus rather quickly

Small range: Delightful cats mostly meow nicely purring furiously and zealously yet rarely quietly

Dogs hate kissing monkeys given that primates eat zesty yuzus rather quickly   Delightful cats mostly meow nicely purring furiously and zealously yet rarely quietly

Secondary School category: Alexa from Beaulieu Convent School

Large range: Dizzy Hot Koalas Mainly Get Tired Patiently Eating Zesty Yellow Round Quinces

Small range: Drunk Chunky Monkeys Munch Nutty Peanut Fudge After Zebras Yell Rude Questions

 

We are pleased to announce our runners up as:

Dizzy Hot Koalas Mainly Get Tired Patiently Eating Zesty Yellow Round Quinces   Drunk Chunky Monkeys Munch Nutty Peanut Fudge After Zebras Yell Rude Questions

Primary School category: Sandra from Beaulieu Primary School

Large range: Daydreaming Hippos Kindly Make Granola Tiramisu Pleasing Each Zebra Yelping Romantic Quotes


Small range: Do Crazy Male Magpies Need Protection From All Zebras Yelling Ridiculous Questions?

Daydreaming Hippos Kindly Make Granola Tiramisu Pleasing Each Zebra Yelping Romantic Quotes    Do Crazy Male Magpies Need Protection From All Zebras Yelling Ridiculous Questions?

Secondary School category: Dorian from Lord Wandsworth College

Large range: During His Kingdom's Mighty Growth, The Prince Enjoyed Zooming on Yellow, Racing Quadbikes


Small range: Dangerously Crossing Mountains Means Navigating Precisely. Find A Zipline, Yell "Rescue!" Quickly!

During His Kingdom's Mighty Growth, The Prince Enjoyed Zooming on Yellow, Racing Quadbikes   Dangerously Crossing Mountains Means Navigating Precisely. Find A Zipline, Yell "Rescue!" Quickly!

Entries now closed

For submissions to be judged, they will need to be shared with NPL by an adult.

  • Submit your entry using the form below.
  • Please only put your first name on entries (no surnames).
  • Entries close midnight Tuesday 28th February 2023.
  • We will only accept entries with a responsible adult’s contact details.
  • Winners will be chosen by a panel of judges at NPL.
  • From 6 March 2023, the responsible adult for each winner and runner up will be notified by email and a selection of entries posted on the NPL website.
  • Winners will receive £200 worth of high-street gift vouchers. Runners up will receive £50 worth of high-street gift vouchers. We will share the best entries on our webpage and feature them on our social media channels including Instagram, Facebook and Twitter.
  • If you like, share your creative entries on social media using #SIprefixchallenge where you can go beyond words and present your entry as a video, animation, song or rap.

Challenge rules

  • The challenge is open to all UK school age children with two judging categories: Primary and Secondary.
  • Entries must be shared with NPL by a responsible adult (who could be a teacher or parent/carer).
  • Ideas involving derogatory comments, dangerous activities, inferred harm to living creatures or rude language are not acceptable.
  • Entries must not contain any private and confidential information.
  • The challenge will run between 21 November 2022 and 28 February 2023 (inclusive) and only entries received in this period will be accepted and considered.

What is an SI prefix? And why are they important?

There is a worldwide agreement between all countries to measure using the International System of Units (SI). Prefixes in this system represent multiples or subdivisions, and make it easier to understand and communicate when numbers get very big or very small.

The internationally agreed SI prefixes can be combined with every SI unit of measurement, for example:

Prefix Name Prefix Symbol Multiplier In practise
milli m one thousandth millimetre (mm) = 0.001 metre = 10-3 metre
milligram (mg)  =  0.001 gram   =  10-3 gram
kilo k one thousand kilometre (km)  =  1000 metre  =  103 metre
kilogram (kg)     = 1000 metre  =  103 metre

 

For this challenge we asked participants to create two mnemonics, one for the SI prefix names for big numbers, and one for the SI prefix names for small numbers. You can see both in the chart below.

Multiplying Factor Name (symbol) Scientific Notation
1 000 000 000 000 000 000 000 000 000 000 quetta (Q) 1030
1 000 000 000 000 000 000 000 000 000 ronna (R) 1027
1 000 000 000 000 000 000 000 000 yotta (Y) 1024
1 000 000 000 000 000 000 000 zetta (Z) 1021
1 000 000 000 000 000 000 exa (E) 1018
1 000 000 000 000 000 peta (P) 1015
1 000 000 000 000 tera (T) 1012
1 000 000 000 giga (G) 109
1 000 000 mega (M) 106
1 000 kilo (k) 103
100 hecto (h) 102
10 deca (da) 101
1   100
0.1 deci (d) 10-1
0.01 centi (c) 10-2
0.001 milli (m) 10-3
0.000 001 micro (µ) 10-6
0.000 000 001 nano (n) 10-9
0.000 000 000 001 pico (p) 10-12
0.000 000 000 000 001 femto (f) 10-15
0.000 000 000 000 000 001 atto (a) 10-18
0.000 000 000 000 000 000 001 zepto (z) 10-21
0.000 000 000 000 000 000 000 001 yocto (y) 10-24
0.000 000 000 000 000 000 000 000 001 ronto (r) 10-27
0.000 000 000 000 000 000 000 000 000 001 quecto (q) 10-30

Here’s an example of mnemonics we have come up with to get you started…

Daringly hungry kangaroos mock gorillas that playfully eat zucchini yet rarely quarrel
deca hecto kilo mega giga tera peta exa zetta yotta ronna quetta
Did centipedes munch my noodles? Please find all zingy yellow racoons quickly
deci centi milli micro nano pico femto atto zepto yocto ronto quecto

 

Find out more about the new SI prefixes

What is a mnemonic?

A mnemonic is a system such as a pattern of letters, ideas, or associations which assists in remembering something. For example, you may have used a mnemonic before to remember the correct the order of the colours of the rainbow, or the order of the planets in space.

Richard of York gave battle in vain
Red Orange Yellow Green Blue Indigo Violet
My very easy method just speeds up nothing
Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune
Did centipedes munch my noodles? Please find all zingy yellow racoons quickly
deci centi milli micro nano pico femto atto zepto yocto ronto quecto