At this very moment, invisible signals are flying through the air all around us. Beyond the spectrum of light our eyes can see, massive radio waves as wide as houses carry information between computers, GPS systems, cell phones, and more. In fact, the signal your phone broadcasts is so strong that if your eyes could see radio waves, your phone would be visible from Jupiter. However, this visibility would be compromised by interference from routers, satellites, and people who haven’t put their phones in airplane mode.
Contrary to popular belief, the airplane mode setting on your phone isn’t to protect your flight but rather to protect everyone else in your flight path. Cell phones connect to networks by emitting information in the form of electromagnetic waves, specifically, radio waves, which occupy a certain band of the electromagnetic spectrum. These radio waves come in a range of wavelengths. When you make a call, your phone generates a radio wave signal which it throws to the nearest cell tower. If you’re far from service, your phone will expend more battery power to send a higher amplitude signal in an effort to make a connection.
Once connected, this signal is relayed between cell towers all the way to your call’s recipient. Since your call isn’t the only signal out here, cell towers managing the calls assign each phone involved their own wavelength. This specific color ensures you’re not picking up other people’s calls. It’s even slightly different from the wavelength your phone is receiving information on, so as not to interfere with that incoming signal. However, with the advent of Wi-Fi, the demand for ownership of these wavelengths has increased dramatically, making avoiding interference increasingly difficult.
Interference becomes particularly problematic when cell towers receive too many signals at once, such as during regional emergencies when everyone’s trying to use their phones. But other sources of interference are more preventable, like phones searching for signals from thousands of meters in the sky. Phones on planes are very far from cell towers, so they work overtime to send the loudest signals they can in search of service. But since planes travel so quickly, the phones might find themselves much closer to a cell tower than expected—blasting it with a massive signal that drowns out those on the ground. So when you fly without using airplane mode, you’re essentially acting as a military radio jammer—sending out giant radio waves that interfere with nearby signals.
Even on the ground, almost all our electronics emit rogue radio waves, slowing down our internet and making our calls choppy. This leads consumers to pay for more bandwidth, pushing service providers to take over more of the radio spectrum, and eventually, send more satellites into the sky—creating a vicious cycle that could eventually blot out the stars. This system is threatening our relationship with the cosmos. Radio telescopes used for astronomy rely on a specific band of wavelengths to see deep into space. However, while this range is supposedly protected, the cutoffs aren’t enforced.
For example, the Very Large Array can see signals throughout our solar system from 1 to 50 GHz. But if it tries looking for signals below 5 GHz, its search could be drowned out by a sea of phones on 5G networks. Today, nowhere on Earth is truly radio-quiet. Satellites relaying signals around the globe have blanketed the planet in radio waves. But there are a few places with less crowded skies, where radio telescopes can look deep into space. Here, we can see the black hole at the center of the Milky Way, and uncover the secrets of galaxies up to 96 billion light years away. Well, so long as we’re not blinded by phones sending signals from first class.
Go on a scavenger hunt around your home or school to identify devices that emit radio waves. Make a list of these devices and categorize them based on their primary function (e.g., communication, entertainment, navigation). Discuss how each device uses radio waves and the potential for interference.
Using materials like string, paper, and markers, create a physical model of radio waves. Show how different wavelengths and amplitudes look. Explain how these differences affect the strength and reach of the signals. Present your model to the class and describe the role of wavelength and amplitude in communication.
Conduct an experiment to observe the effects of airplane mode on your phone’s battery life. Use your phone normally for a day and record the battery usage. Then, use it with airplane mode on for another day and compare the results. Discuss why airplane mode conserves battery and how it reduces interference.
Play a game where you simulate managing a network of cell towers. Use colored strings to represent different wavelengths and assign each student a “phone” (a small object). Try to connect calls without strings crossing each other. This will help you understand how cell towers manage multiple signals and avoid interference.
Participate in a classroom debate on the regulation of radio waves. Split into two groups: one advocating for stricter regulations to protect astronomy and another arguing for the needs of modern communication. Research your positions and present arguments, considering the impact on both technology and science.
invisible signals – Signals that cannot be seen by the human eye. – The invisible signals from the remote control are used to change the TV channel.
radio waves – Electromagnetic waves with long wavelengths and low frequencies are used for wireless communication. – Radio waves are used to transmit signals from the radio station to your car’s receiver.
electromagnetic waves – Waves of electric and magnetic energy that travel together through space. – Electromagnetic waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
wavelength – The distance between two corresponding points on a wave, such as the peak to peak or trough to trough. – The wavelength of a radio wave determines the frequency at which it operates.
amplitude – The maximum height or value of a wave from its equilibrium position. – The amplitude of a sound wave determines its volume or loudness.
cell towers – Tall structures equipped with antennas that transmit and receive signals to and from mobile devices. – Cell towers are essential for maintaining a strong cellular network connection.
interference – The disruption or distortion of a signal caused by unwanted electrical or electromagnetic signals. – The baby monitor was experiencing interference from a nearby cordless phone.
airplane mode – A setting on mobile devices that disables all wireless communication to comply with airplane safety regulations. – Remember to switch your phone to airplane mode before the flight takes off.
bandwidth – The maximum amount of data that can be transmitted over a network connection in a given amount of time. – High-speed internet plans offer larger bandwidth, allowing for faster downloads and streaming.
radio spectrum – The range of frequencies used for radio communication, divided into different bands. – The FM band in the radio spectrum is typically used for broadcasting music and talk shows.
