Every time you turn on the radio to listen to some music, you’re taking advantage of decades of excellent physics research between the 19th and early 20th centuries. As light, radio waves are oscillating electromagnetic waves, produced by vibrating electrical charges. Their oscillations, however, are much less rapid than those of light waves (about one million oscillations per second for radio waves, while light oscillates almost a billion times faster!).Towards the end of the 19th century, researchers realized that radio waves could be used to transfer information without wires between distant locations. Marconi, an Italian physicist, made many important contributions in this field. In particular, his major achievement was the first transatlantic radio communication. At the time this was a great surprise because physicists generally believed that radio waves could only travel along a line of sight path, limiting its range to the visual horizon. Sceptics suggested that, due to the curvature of the Earth, radio waves would just escape into the atmosphere, making it impossible to link two points very far away. Luckily for Marconi, however, it turns out that the atmosphere includes a layer of ionized particles, called the ionosphere, which reflects radio waves back to Earth, enabling long-distance communication. He won the Nobel Prize in Physics in 1909.
Want to learn more?
The study of electromagnetic waves is fundamental to all Heriot-Watt physics degree programmes (2nd year course B28PO Photonics and Optics, 3rd year course B29EM Electromagnetism and 4th year course B20ES Electromagnetism and Laser Physics). Radio waves are routinely used, for example, in the Quantum Photonics Lab at Heriot-Watt to control the magnetization of single atomic nuclei and summer internships and final year projects provide excellent opportunities to get to grips with this cutting edge science in a “hands-on” research environment.