Sue - Teaching Notes

7/26/2019 Sue - Teaching Notes

1/18

CODESFirst edition

Material to support teacher use of the CD-ROM

In the second edition of these notes, we are planning to include a

treasure trail, in which each code gives the ke to the ne!t code"

Background reading:

The Code Book by Simon Singh

#uthors$

Sue %ohnston-&ilder, Open 'niversit

%osephine (urgess, (urgone Middle School

with help fro)

#nita #ggarwal, De Montfort 'niversit

*reg Morris, Milton +enes E#

Si)on Singh, author

ick Mee, .irtual I)age

/rac %ohns,Open 'niversit

#le! &ilder, Ralph (utterfield 0ri)ar School

and the Maths Clu1 of (urgone Middle School

Codes Teacher Resource Page 1


2/18

Introduction/he CD-ROM contains )ore than 23 encrption tools that ena1le

ou to encode4encrpt our )essages in different was"

/o find these tools 5uickl, click on the 6 icon 7top right8 to

access the contents page" 9ou can use the search engine on the

contents page to find a particular topic" For e!a)ple, tpe in

0igpen or Enig)a and click on Search" Encrption tools are

)arked with an E"

/he activit pages are designed to give ou so)e 5uick ideas for

using the CD-ROM with children aged : to ;


3/18

A simple substitution the Pigpen Cipher

'sing the 0igpen encrptor on the CD-ROM, tpe in our na)e and

encipher it"

&ork out how the cipher works"

'se the 0igpen cipher to decipher the following fa)iliar

)athe)atical words$

and

ow encode a secret )essage of our own and ask a friend to

decode it"



4/18

The Pigpen Cipher teachers notes

Curriculu)$ pro1le) solving and voca1ular

Suggested prior e!perience$ none

This is a good activity to introduce the idea of encoding or encipheringand decoding or deciphering messages.

The children can enter messages into the box marked plaintext. When theyclick the button marked Encipher Plaintext it takes a moment then puts theencrypted text into the box below.

ost children will pick up the code from the diagrams. !f they dont"encourage them to type in the alphabet in groups of # letters at a time andencode it.

says parallelogram

and

says $uadrilateral



5/18

The Caesar Wheel

Make a Caesar &heel fro) the te)plate on the CD-ROM"

&orking with a partner, encode the na)e of our school"Check ou 1oth have the sa)e result"

Move the wheel to a new position that our partner doesn?t see"

ow encode our na)e"

#sk our partner to work out how ou positioned the wheel"

Choose a new position of the wheel"

Encode a short secret )essage for our partner"



6/18

The Caesar Wheel

/here is a te)plate on the CD-ROM for a Caesar &heel"

!t can be printed out in advance of the lesson.

This activity introduces the notion of a key to a cipher. The cipher is the%aesar Wheel and the key is the number of displacements.

!t is an interesting code to decipher in that if you try the wrong key you getrubbish" but when you try the right one the message suddenly makes sense.



7/18

Decoding messages

'sing the Caesar Cipher, tr to decode the following )essage$

@+AB (R +D9A *AFR*A* &+. @R' R& &@AB&(.A9AB &0A. BBA DB* &AOO (R' &ADF+A'

9ou could tr

/rial and error

Focusing on ust one word

#nother wa

/r this one

ASE O@ %@F && O/9@DFC A/ES @90 0%0

O@%@FES/9.S0DAFD

ow use the Caesar Shift encrption tool on the CD-ROM toencode a )essage of our own"

0rint out 1oth the )essage and the encrption"

Cover up the )essage and see if our friend can work it out"



8/18

Decoding messages teachers notes

Curriculu)$ pre-functions

Suggested prior e!perience$ none

The first message says&

When you have decoded this work out twenty seven

times nine and tell your teacher

The second message says&

What do you call a dinosaur with one eye

' doyouthinkhesawus

When the children use the %aesar (hift encryption tool" they can choose thedistance of the character shift.

They type the message into the Plaintext box.

They can either encrypt the message

a letter at a time )*etter Encrypt+

the whole message at once ),ast Encrypt+

The Print %iphertext button offers an option to print Plaintext" %iphertext orboth.



9/18

Scrabble

Construct a graph of the fre5uenc of scra11le letters in a set"

Construct a graph of the tile scores"Co))ent on the si)ilarities and differences"



10/18

Scrabble teachers notes

0

2

4

6

8

10

12

14

A B C D E F G H I J K L M N O P Q R S T U V W X Y

' graph of the fre$uency of scrabble letters in a set" not including blanks.

0

2

4

6

8

10

12


' graph of the scrabble scores.

!f the children have difficulty describing the pattern" they could construct thegraph of -score and compare that with the fre$uency graph instead.

0

0!2

0!4

0!6

0!8

1

1!2


' graph of -score.



11/18

Letter Freuencies

Choose a page of our reading 1ook"

Count a hundred letters"Make a fre5uenc ta1le"

0ut the results of the whole class into a spreadsheet"

Calculate the )ean fre5uenc for each letter, rounded to the

nearest whole nu)1er"

&hich is the )ost co))on letter used in our sa)ple6

&hich are the ne!t )ost co))on letters6

&hich letters occur )ost rarel6

Co)pare our results with the scra11le fre5uencies"

Co))ent on an differences ou find"



12/18

Letter Freuencies teachers notes

Curriculu)$ data handling and graphs

Suggested prior e!perience$ fre5uenc ta1les and graphs

The %/012 has materials about the early use of letter fre$uency analysis"in 3aghdad.

2nce the children have met the idea of fre$uency analysis they can use it todecode messages such as the one in the next activity.

Fre5uenc of letters in English writing



13/18

The !abington Plot

/he following note has 1een coded using the cipher actuall used

1 Mar Bueen of Scots"

Can ou crack it6

Carr out an analsis of the fre5uenc of each character

De-code the )essage



14/18

Fre5uenc ta1le

S)1ol /all Fre5uenc

G

O

H

C

f

M

:

5

/otal H;



15/18

Fre5uenc ta1le - answers

S)1ol /all Fre5uenc

;G J

O :

H

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Sue - Teaching Notes