Western Union telegraph key and repeater, 1875-1900

On August 16th, 1858, Queen Victoria became one of the first individuals to send a message across an ocean. Travelling across thousands of miles of cables over the course of sixteen hours, she successfully telegraphed a message to then-U.S. President James Buchanan.

Despite the lengthy time to send the missive, how a telegraph works is through simple circuitry, so simple that its principles can be reproduced within a classroom rather than a throne room. In this activity, students will make a circuit that they will be able to reconnect and break repeatedly and easily, just like a telegraph machine does.

3 4-inch lengths of wire, with the ends stripped to show the copper

1.      Cut the cardstock into a thin strip, about one inch wide and four inches long. Fold in half, width-wise, and tape on of the flat ends to your work surface so that it opens upwards.

2.      Cut squares, 1 inch by 1 inch, of aluminum foil and fold both in half. Glue one half of the aluminum squares to each end of the cardstock strip. The aluminum squares should touch when pressing down on the cardstock, and come apart when released. This will be your “telegraph machine.”

3.      Place one piece of wire between the two halves of the aluminum foil on one end of the cardstock strip. Repeat for the other end, using a different wire. Tape the foil down so it forms a “sandwich” with the stripped wire end between the aluminum foil halves.

4.      Attach the other end of one of your aluminum- wire combinations to an LED bulb. 

5.      Attach the other aluminum-wire combination to a battery

6.      Taking the third wire (which is not attached to anything at the moment) and use it to link the battery and the LED. Remember! Just like the battery has a + and - side, so does the LED bulb.

7.      Push down on the top half of the cardstock so that the aluminum foil meets its pair on the bottom half of the cardstock. If wired correctly, the circuit will be complete and the bulb will light as they touch, and turn off as they separate.

Standards for Making a Simple Telegraph