Communication by Electricity

Code Lights

Telegraph key and repeater, Western Union, 1875-1900

Description

The major benefit of the development of morse code and telegraphy was the ability to send messages not only over long distances, but also the ability to encrypt messages so that they would not be heard by unwanted parties. For example, during World War II, ships could communicate with one another over shared airwaves to deliver information and plans to allies, but that could easily be intercepted by enemy ships. With codes, however, direct translation on the part of the unwanted listeners would be made more difficult, rather than if they had listened to a known, spoken language. Some of the codes used during World War II include the Enigma and Lorenz messages, used by the Germans, and the Native American code talkers of the United States.

In this activity, students will work together to explore how distance impacts communication and how the use of technology can impact the quality of transmitted messages. Students will also come up with their own codes, or can continue to practice Morse Code.

Materials

Flashlights of varying sizes A large, open space (school yard or football field) Paper Pencils Clipboards A set of short messages to be handed out at the beginning of the activity (unseen by students until ready) Optional: Morse code sheet

Outline

1.      Students can work in pairs, small groups, or as a class. If desired, have students spend time developing their own codes that can be translated into flashlight flashes.

2.      Have students go outside and spread out, with one student holding the flashlight and code sheet, if using, and the other with a pencil, paper, clipboard, and their own code sheet

3.      Give each flashlight-student a copy of the message they will be sending to their partner. Students should not see these messages ahead of time.

4.      As students flash the light on and off to send their message, their partner/ group mates should attempt to translate it. How accurate was the sending/ receiving of the messages? What worked/ didn’t work about their own codes vs. morse code?

Extended Activity

This activity can be altered in multiple ways to increase/ decrease difficulty:

·        Have students shout a different message first from the same distance. How does the accuracy compare with the message sent by flashes?

·        Instead of standing across from their partner/ group in lines, have students spread out in a “cloud” to simulate ships on an ocean. Does the yelling/ light flashing from other students affect the messages?