Computers are often used to store private information, and we often want to share parts of it without giving up our full privacy.
This activity shows a surprising technique discovered by computer scientists that seems impossible; it allows people to share personal certain kinds of information accurately without having to give up any privacy at all.
The Mathmaniacs web site has a similar activity (lesson B).
Try Engineering has an activity called Electric Messages: Then and Now which explores electronic communication, the Morse Code system, and advances all the way through text messaging. Students build a simple circuit, send messages to one another. and explore the impact of electrical communications on society. Download Full Lesson Plan and Student Worksheets.