sue - teaching notes
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7/26/2019 Sue - Teaching Notes
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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
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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 ;
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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"
Codes Teacher Resource Page 3
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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 $uadrilateral
Codes Teacher Resource Page 4
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The Caesar Wheel
Make a Caesar &heel fro) the te)plate on the CD-ROM"
&orking with a partner, encode the na)e of our school"Check ou 1oth have the sa)e result"
Move the wheel to a new position that our partner doesn?t see"
ow encode our na)e"
#sk our partner to work out how ou positioned the wheel"
Choose a new position of the wheel"
Encode a short secret )essage for our partner"
Codes Teacher Resource Page 5
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The Caesar Wheel
/here is a te)plate on the CD-ROM for a Caesar &heel"
!t can be printed out in advance of the lesson.
This activity introduces the notion of a key to a cipher. The cipher is the%aesar Wheel and the key is the number of displacements.
!t is an interesting code to decipher in that if you try the wrong key you getrubbish" but when you try the right one the message suddenly makes sense.
Codes Teacher Resource Page 6
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Decoding messages
'sing the Caesar Cipher, tr to decode the following )essage$
@+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"
Codes Teacher Resource Page 7
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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.
Codes Teacher Resource Page 8
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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"
Codes Teacher Resource Page 9
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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$uency of scrabble letters in a set" not including blanks.
0
2
4
6
8
10
12
A B C D E F G H I J K L M N O P Q R S T U V W X Y
' graph of the scrabble scores.
!f the children have difficulty describing the pattern" they could construct thegraph of -score and compare that with the fre$uency graph instead.
0
0!2
0!4
0!6
0!8
1
1!2
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 -score.
Codes Teacher Resource Page 10
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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"
Codes Teacher Resource Page 11
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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
Codes Teacher Resource Page 12
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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
Codes Teacher Resource Page 13
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Fre5uenc ta1le
S)1ol /all Fre5uenc
G
O
H
C
f
M
:
5
/otal H;
Codes Teacher Resource Page 14
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Fre5uenc ta1le - answers
S)1ol /all Fre5uenc
;G J
O :
H
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