Talking across distance
Before the telephone, the fastest way to send a message far away was the telegraph, which used coded clicks (Morse code). You couldn’t hear a person’s voice. The telephone changed that by turning the human voice into electrical signals.
The invention
Alexander Graham Bell was born in Scotland in 1847 and moved with his family to Brantford, Ontario, in 1870. His mother was deaf, and he became a teacher of deaf students. His work on sound and speech led him to experiment with sending voices over wires.
| Date | Event |
|---|---|
| 1874 | Bell came up with the idea for the telephone while at his family’s home in Brantford |
| February 14, 1876 | Bell filed a patent for the telephone in the United States, just hours before Elisha Gray filed a similar idea |
| March 10, 1876 | First successful call: "Mr. Watson, come here, I want to see you," spoken to his assistant Thomas Watson in Boston |
| August 10, 1876 | First long-distance call, about 13 km between Brantford and Paris, Ontario |
Several other inventors, including Elisha Gray and Antonio Meucci, worked on similar ideas. In 2002, the U.S. House of Representatives passed a resolution recognizing Meucci’s earlier work. Who deserves credit is still debated, but Bell received the patent and built the first successful telephone company.
Bell later explained that the telephone was conceived in Brantford and born in Boston, where he built and tested it.
How early telephones worked
| Part | Job |
|---|---|
| Transmitter (mouthpiece) | Sound waves vibrate a thin diaphragm, which changes an electric current to match the sound |
| Wire | Carries the changing current |
| Receiver (earpiece) | The changing current moves an electromagnet that vibrates another diaphragm, recreating the sound |
Early telephone lines connected only two places. As more people got phones, calls were connected through a central office with a switchboard, where operators plugged in cables by hand.
Telephones over time
| Year | Development |
|---|---|
| 1878 | First telephone exchanges; first telephone directories |
| 1880 | Bell Telephone Company of Canada founded |
| 1891 | Automatic switching invented, replacing operators over time |
| 1915 | First transcontinental call across the U.S. |
| 1927 | First transatlantic phone call (by radio) |
| 1956 | First transatlantic telephone cable |
| 1963 | Touch-tone dialling introduced |
| 1973 | First mobile phone call (Martin Cooper of Motorola) |
| 1979–1985 | First cellular networks open in Japan, the U.S. and Canada |
| 2007 | Touchscreen smartphones become popular |
How mobile phones work
Mobile phones use radio waves instead of wires. A cellular network divides an area into small regions called cells, each with a tower. As you move, your call is handed from one tower to the next. Your voice is turned into digital data and sent as radio signals.
How the telephone changed life
- Families and friends could talk across great distances.
- Businesses could communicate instantly.
- Emergency services became easy to reach (911 was introduced in Canada starting in 1972 in Winnipeg).
- Telephone lines later carried internet data.
- Today’s smartphones combine the telephone with a camera, computer and much more.
Bell’s other work
Bell also worked on:
- the photophone, which sent sound on a beam of light (a forerunner of fibre optics)
- hydrofoil boats: his HD-4 set a world water speed record in 1919 on the Bras d’Or Lake near Baddeck, Nova Scotia
- the Silver Dart, which in 1909 made the first powered flight in Canada, at Baddeck
The Alexander Graham Bell National Historic Site in Baddeck and the Bell Homestead in Brantford celebrate his work.
Common mistakes
- Thinking the telephone was invented in one moment by one person.
- Thinking mobile phones use wires. They use radio waves.
Try it yourself
- Make a cup-and-string telephone. Does it work better with the string tight or loose? Why?
- Interview a grandparent about using rotary or party-line phones.
- Draw a diagram showing how sound becomes an electrical signal and back again.
Quick recap
- The telephone turns sound into electrical signals and back again.
- Alexander Graham Bell, who lived in Brantford, Ontario, patented it in 1876.
- Early calls were connected by operators at switchboards.
- Mobile phones use radio waves and cellular networks.
- The telephone transformed communication and led to the smartphone.