As part of our studies, we've been having lots of fun with invisible ink (made from a variety of household materials) and ciphers. We learned that Thomas Jefferson invented something called the Jefferson Disc Cipher (sometimes called a wheel cipher or Bazeries cylinder; you can see an image of it to the left). It worked so well, the American government continued to use it right on up to WWII! You can read more about the Jefferson Disc Cipher at Wikipedia and CipherMachines.com.
Online, I found a number of sites that suggested ways to make a disc cipher; one recommended collecting mayonnaise lids for the discs - but it would take us a long time to go through enough mayo to get the required number of lids. Another suggested ribbon spools, but I didn't have any on hand. And others suggested just using paper - but the directions were either non-existent or confusing. In the end, I made our own paper template, which you can download for free by clicking the link below.
Free Jefferson Disc Cipher Printable (.PDF)
My kids absolutely love this simple cipher! They've spent hours creating and deciphering messages with each other. Maybe they need a nice wooden one that will last; they sell them at Monticello, and at Amazon. We'll see.
How to Make a Simple Jefferson Wheel Cipher
You will need:
Printed "free Jefferson Disc Cipher Printable" (see above link)
An empty toilet paper tube (or empty paper towel tube)
1. Cut out the columns of letters. There will be 7 strips. (If using a paper towel tube, you will need to print out more than one sheet of letters.)