Modern earphones were designed by Nathaniel Baldwin, who submitted his ideas to the Navy for testing in 1910. However, there were many designs of in-ear pieces that predated Baldwin's and contributed to his ideas.Know More
Stethoscopes were one of the earliest in-ear devices. In the 1850s, they were invented for listening to a patient's heart and lungs, and Thomas Edison used them with his phonograph machine. In the 1890s, British opera houses and theaters started supplying the audience with rudimentary headphones. In 1891, Ernest Mercadier invented the bi-telephone, a pair of earbuds that blocked out noise.
With the Navy's guidance, Baldwin's final design consisted of two sound receivers, each containing a mile of copper wiring, attached to the operator's headband. This design was the foundation for electricity-free telephones used in World War II.
John Koss then developed the first commercialized stereo headphones in 1958. In 1979, Sony invented the Walkman.Learn More
William Morton first demonstrated the use of ether as an anesthetic, but no one knows who actually invented anesthesia. After Morton's demonstration at Massachusetts General Hospital, several people came forward claiming they had discovered anesthesia much earlier.Full Answer >
Several products and procedures were invented in 1974. One example is the Post-It Note, which was created by American Arthur Fry. Since their invention, Post-It Notes have been sold in over 100 countries across the world and are still used over 40 years later.Full Answer >
The concept of mapping the Earth using two sets of parallel lines, one running from north to south and the other from east to west, was first utilized by the Greek Eratosthenes. Hipparchus, another Greek, was the first to use these lines as coordinates for specific locations.Full Answer >
Modern ice hockey rules were created by Canadian athlete, journalist and lawyer James George Aylwin Creighton. The first game of modern ice hockey was played in 1875 in Montreal, Canada. Ice hockey likely evolved from field hockey played in Northern Europe.Full Answer >