Publication No. 14079
Historical Inventions Laboratory Kit
Materials Included In Kit
Alligator clips, black, 20
Alligator clips, red, 20
Contact keys, 10
Iron nails, 2", 10
Iron strips, 10
Light bulbs, miniature, 3.7-V, 10
Light bulb receptacles, 10
Magnet wire, 600-ft spool, 30 gauge
Pink foam bases, 5" x 10", 10
Sandpaper, 9" x 11"
Additional Materials Required
(for each lab group)
Batteries, D-cell, 1.5 V, 2
Battery holders, 2
1-kg weight or equivalent
While the batteries are not harmful, small shocks are possible. Do not complete the circuit with the battery for more than ten-second intervals. Since there is very little resistance in the wires, the battery can discharge quickly and become very hot if it is connected for a longer duration. Care should be taken when wrapping and unwrapping the wire. The pointed ends of the wire are hazardous to eyes. Wear safety glasses. Please follow normal laboratory safety guidelines.
Supplemental Material: International Morse Code
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering PracticesAsking questions and defining problems
Planning and carrying out investigations
Obtaining, evaluation, and communicating information
Engaging in argument from evidence
Analyzing and interpreting data
Disciplinary Core IdeasMS-PS4.C: Information Technologies and Instrumentation
HS-PS2.B: Types of Interactions
Crosscutting ConceptsEnergy and matter
Systems and system models
MS-PS4-3. Integrate qualitative scientific and technical information to support the claim that digitized signals are a more reliable way to encode and transmit information than analog signals.
Answers to Prelab Questions
Answers to Questions
In today’s modern age we are accustomed to light-speed telecommunication thanks to smartphones, the internet, and ever faster computers… but it was not always this way! Create one of the first forms of “fast” telecommunication with the construction of your very own telegraph. Discover the usefulness of the electromagnet, send messages with Morse code and gain an appreciation for the speed at which we send and receive information today.
The word telegraph is derived from the Greek words tele, meaning far, and graphein, meaning write, and is defined as any system that allows for transmission of encoded information by signal across a distance. The term telegraph, however, is most often used when referring to the electrical telegraph that was developed in the 19th century. In 1819, Hans Christian Oersted (1777–1851) discovered that a current-carrying wire could deflect a magnetized compass needle. In 1824, British inventor William Sturgeon (1783–1850), discovered the electromagnet. An electromagnet is simply a current-carrying wire coiled around a ferromagnetic material, such as a piece of iron. It was found that a current-carrying wire wound around the metal core would create a magnet whose magnetic properties could be switched on or off by simply switching the current on or off. The scientific community continued to improve on the apparatus. In 1830, Joseph Henry (1797–1878) successfully implemented an electromagnet into the telegraph, and demonstrated the possibility of using a telegraph for long-distance communication. Henry sent an electric current over a mile of wire to activate an electromagnet that caused a bell to strike. This was the first iteration of the electric telegraph.
The goal of this laboratory activity is to gain an understanding of how a telegraph system works by building a simple wired telegraph. The circuit components required for the system to function are studied as well as the electromagnetic phenomena that allowed for more efficient long-distance communication.
Alligator clip wire, black, 2
Alligator clip wire, red, 2
Batteries, D-cell, 1.5-V, 2
Battery holders, 2
Iron nail, 2"
Light bulb, miniature, 3.7-V
Light bulb receptacle
Magnet wire, 5 meters
Pink foam base
Weight, 1 kg
While the batteries are not harmful, small shocks are possible. Do not complete the circuit with the battery for more than ten-second intervals. Since there is very little resistance in the wires, the battery can discharge quickly and become very hot if it is connected for a longer duration. Care should be taken when wrapping and unwrapping the wire. The pointed ends of the wire may be sharp. Wear safety glasses. Please follow normal laboratory safety guidelines.
Student Worksheet PDF