Samuel Morse hit on the idea of transmitting coded messages down a wire in 1836. This was better than sending letters with Pony Express that could take days and sometimes weeks.
Morse transmitted long and short coded electric pulses down the wire instead, and these went through right away.
Today, we are going to explain how to make a telegraph with a nine-volt battery, and a few other simple things using electromagnetism. Morse Code uses sets of long and short combinations of pulses for letters and numbers. There’s a link to the complete list at the end of this post. But by way of an example, here’s ‘battery’ spelled in Morse.
-… .- – – . .-. -.–
B A T T E R Y
Doctors still use this method to communicate with people with severe disabilities, although modern cellular and internet communication largely replaced it. Urban legend tells the story of a shipboard telegraph operator who lost his voice. Apparently he communicated successfully with his doctor by blinking his eyes in Morse Code.
Now We Understand the Idea, Let’s Make a Telegraph
To make a telegraph sender and receiver along the same lines as the video, you’ll need a nine-volt battery, some copper wire, and a nice shiny six-inch nail. You also need a couple of small pieces of wood, a thin copper plate, and some copper screws.
TO MAKE THE SENDER
Take a piece of wood roughly 2 inches by 4 inches by under 1 inch thick. First, cut out a piece of copper plate say half an inch by two half inches. Next, bend the plate in the middle and screw half to the piece of wood. Finally, position a copper screw under this so the plate will press against it when you push the plate down with your finger.
TO MAKE THE RECEIVER
First, glue two other pieces of wood together to create an L-shape. Then, drive the nail into the bottom one, but not through. Wind the copper wire one hundred times around this nail in a tight spiral with both ends protruding. Cut, bend, and fix another piece of copper sheet to the vertical of the L. The piece sticking out must be just above the nail head.
TO CONDUCT THE EXPERIMENT
Connect the copper plate on the SENDER to one end of the RECEIVER coil using a piece of copper wire. Use a second piece of copper wire to join the SENDER copper screw to one battery terminal. Finally connect the other battery terminal to the other end of the RECEIVER coil. Repeatedly press the SENDER plate so it makes and breaks contact with the copper nail. Now watch the action at the RECEIVER end. Learn by experimenting how to make a telegraph send long and short pulses using electromagnetism. Now write and tell us the scientific principles behind this.
Preview Image: 1904 Illustration of Old Telegraph
Video Share Link: https://youtu.be/3aM7AxBGg8Q