Radio waves are known to have the longest wavelengths1 and smallest frequencies2 in the electromagnetic system. Their wavelengths range from 30 cm to thousands of meters and their frequency can range from as low as 3 Hz to 1 GHz (equivalent to 1 x 10^9 Hz). To visualize the vast size of radio waves, radio waves can be seen to range from the size of a football field to being larger than our planet comparatively.
Radio waves were first mathematically predicted by Scottish physicist James Clerk Maxwell. This mathematical theory is now termed as “Maxwell’s equations,” and it predicted that electric and magnetic fields could travel through space together as “electromagnetic waves.”
This idea was later proven to exist by German physicist Heinrich Rudolph Hertz in the late 1800s through a series of experiments. After reading Maxwell’s papers, Hertz experimentally tested Maxwell’s theory using a spark gap that was attached to an induction coil and then to a separate spark gap on a receiving antenna. Through this experiment Hertz found that radio waves exhibited the same wave properties of light (for example structure, polarization, diffraction, etc).
Since many astronomical objects in the universe emit radio waves, radio telescopes were developed to be able to create images from detecting the radio waves emitted by these bodies. Studying the radio waves being emitted by astronomical objects allows astronomers to be able to learn about the specific objects’ composition, density, structure, and motion.
Radios utilize radio waves by emitting and receiving radio waves. While listening to music through a radio, the receiver picks up the radio wave and converts it into the sound that comes out of the radio’s speakers. There are two main channels to listen to the radio with radio waves – AM (Amplitude Modulation) and FM (Frequency Modulation). These two channels differ based on the frequency on which they operate: AM having a range of 535 to 1605 kHz and FM having a frequency range from 88 to 108 MHz. When changing between stations, the frequency range being received then broadcasted is changed.
Very similar to the radio, radio waves can be used in television to receive and then broadcast signals onto the screen after being transformed to visual images.
Radio waves are a very important part of the electromagnetic spectrum that is utilized in everyday life often. Known for having a long wavelength and short frequency, radio waves are able to be implemented into uses such as telescopes, radios, and televisions to just name a few.
1 A wavelength is defined by the distance a wave takes to complete one cycle (NASA, 2022)
2 Frequency is the number of cycles a wave repeats in a second (NASA, 2022)
NASA. (n.d.). Radio Waves. NASA. Retrieved March 21, 2022, from https://science.nasa.gov/ems/05_radiowaves
Dunbar, B. (2015, May 6). What are radio waves? NASA. Retrieved March 21, 2022, from https://www.nasa.gov/directorates/heo/scan/communications/outreach/funfacts/what_are_radio_waves
Center for Science Education. Radio Waves | Center for Science Education. (n.d.). Retrieved March 21, 2022, from https://scied.ucar.edu/learning-zone/atmosphere/radio-waves Library exhibits. Omeka RSS. (n.d.). Retrieved March 21, 2022, from https://exhibits.library.gsu.edu/current/exhibits/show/georgiaradio/radio1920s/howradioworks