Secret messages and codes
This information may increase your power to keep a secret …
Invisible Messages
Want to send a secret note to a friend?
One simple way to do this is to place one piece of paper on top of another. Write your message on the top piece of paper in biro or pencil, pressing down firmly.
Give the bottom piece of paper to your friend. Your message won't be visible to the naked eye, but it will be indented into the paper. Lightly rubbing with pencil over the area will reveal the message!
Or, how about writing secret messages in 'invisible ink'? Lemon juice, lime juice, apple juice, onion juice, milk, diluted cola drink or vinegar can all be used to write invisible messages. Use the liquid to write on a plain piece of paper. You'll be able to see what you're writing, but once it dries, it disappears.
To reveal the message, carefully heat the paper. You could iron it, put it on a heater, or use a hair dryer. Remember that paper is flammable and as with all hot things and electrical appliances, make sure you check with your parents first!
Codes
Try writing your secret messages in one of these three codes.
1. One of the best-known codes substitutes numbers for letters of the alphabet:
a=1
b=2
c=3
etc.
So 'Secret' is '19.5.3.18.5.20'
2. Another code substitutes each letter with the next letter in the alphabet:
a becomes b
l becomes m
s becomes t
z becomes a
etc.
So 'Secret' is 'Tfdsfu'.
3. The code which Cass and Max solve at the end of The Name of this Book is Secret is a keyword code, which means the first letters of the alphabet are replaced by a secret codeword.
To see how this works and practise using all of these codes, download our code practice sheet.
Code names
Make messages to your friends even more secret by disguising your identities with code names.
Create your code names using facts that only you and your friends would know about each other.
You could use each person's favourite colour and animal – 'Blue Deer', 'Red Tiger'.
Or, one of their best qualities – 'Speedy', 'Loyal'.
Or you could give them a 'code number' based on their birthday. If you were born on 1/7/98, you could be 1+7+98 = 106.
