Electromagnetic waves. Theory, propagation and applications

12/04/2026

The online electromagnetic wave simulations on this page show how radio waves, microwaves and lasers are generated, propagated and interact. They help us understand the different ranges of the electromagnetic spectrum and their associated phenomena, providing a solid foundation for grasping electromagnetic wave propagation and its applications in communications, technology and science.

What are electromagnetic waves

Electromagnetic waves are periodic disturbances of electric and magnetic fields that travel through space, carrying energy. Electromagnetic waves cover a broad range of frequencies, from radio waves to gamma rays, and include familiar phenomena such as visible light. Studying them allows us to understand how energy travels through different media and lays the groundwork for key technological applications in communications, medicine and science.

Electromagnetic spectrum

The electromagnetic spectrum includes all possible electromagnetic waves, arranged according to their frequency or wavelength. From low-frequency waves such as radio waves to high-energy radiation like gamma rays, each range has unique characteristics and applications. Understanding this spectrum is essential for studying physical phenomena and developing technologies in telecommunications, medicine, astronomy and other fields.

Radio waves

These have the lowest frequency and longest wavelength. They are mainly used in communications, broadcasting and radar.

Microwaves

Microwaves have shorter wavelengths than radio waves and are used in telecommunications, radar and microwave ovens.

Infrared

Infrared waves are associated with heat and are used in thermography, remote controls and sensors.

Visible light

This is the part of the spectrum detectable by the human eye and forms the basis of vision, photography and many optical technologies.

Ultraviolet

Ultraviolet light has more energy than visible light and is used in sterilisation, fluorescence and atmospheric studies.

X-rays

With high energy, X-rays can penetrate tissues and materials, making them essential in medicine, security and structural analysis.

Gamma rays

Gamma rays have the highest energy and are used in medicine, nuclear physics and astrophysics to study high-energy processes.

Propagation of electromagnetic waves

The propagation of electromagnetic waves describes how these waves travel through different media, interacting with matter and with electric and magnetic fields. Understanding the mechanisms of electromagnetic wave propagation helps explain phenomena such as signal transmission, reflection, refraction and attenuation, which are fundamental for engineering and communications.

Propagation in vacuum

In a vacuum, electromagnetic waves travel at the speed of light without loss of energy, maintaining their frequency and wavelength.

Propagation in material media

When passing through air, water or solids, waves may change speed and direction due to refraction, dispersion and absorption, which affects their reach and quality.

Reflection and refraction

Waves may be reflected by conductive surfaces or refracted when passing between different media, key phenomena in antennas, optics and telecommunications.

Attenuation and dispersion

During propagation, the energy of the wave may decrease (attenuation) or disperse, affecting the intensity and clarity of the signal. This is relevant for radio, microwaves and fibre optics.

Polarisation

This describes the orientation of the wave’s electric field and allows control over the direction and effects of waves, applicable in antennas and optical filters.

Applications of electromagnetic waves

Electromagnetic waves are the basis of multiple technologies we use daily and of advanced communication and diagnostic systems. They enable information transmission via radio, television, mobile phones and wireless internet. Their ability to interact with matter is also harnessed in radar, global positioning systems, medical imaging technologies such as magnetic resonance imaging, and in security and industrial control devices. In addition, high-frequency waves like microwaves and lasers are essential in telecommunications, scientific research and military applications. Understanding these applications helps to relate theoretical concepts to concrete phenomena and real-world technologies.

Explore the exciting STEM world with our free, online, simulations and accompanying companion courses! With them you’ll be able to experience and learn hands-on. Take this opportunity to immerse yourself in virtual experiences while advancing your education – awaken your scientific curiosity and discover all that the STEM world has to offer!

Electromagnetic wave simulations

Radio
Propagation
Spectrum
Microwaves
Lasers

Radio waves

This radio wave simulation allows you to explore how these electromagnetic waves are generated and propagated in space. You can visualize phenomena such as reflection, interference and diffraction, as well as the relationship between frequency and wavelength, helping to understand fundamental concepts for wireless communications.

Generation and propagation of electromagnetic waves

Esta simulación ilustra la generación y propagación de ondas electromagnéticas. Muestra la relación entre los campos eléctricos y magnéticos, así como conceptos de frecuencia, longitud de onda y velocidad de propagación.

Electromagnetic spectrum

This simulation allows you to explore the electromagnetic spectrum, showing the different types of waves, their frequency, wavelength and typical applications. It is useful for understanding how electromagnetic waves are classified and their relevance in various technologies.

Microwaves

This microwave simulation shows how microwaves, which are electromagnetic waves of higher frequency than radio waves, interact with different materials. You can study absorption, reflection and transmission, providing practical insight into technologies such as microwave ovens, radar and high-frequency telecommunications.

Lasers

This laser simulation allows you to visualize how a coherent beam of light is generated and how this form of electromagnetic wave propagates. You can observe the direction, intensity and wavelength of the laser, as well as its interaction with materials, which helps to understand its application in communications, medicine, scientific research and industry.

Giants of science

“If I have seen further, it is by standing on the shoulders of giants”

Isaac Newton

André-Marie Ampère

1775

–

1836

André-Marie Ampère formulated the theory of electromagnetism, establishing the mathematical foundations linking electricity and magnetism

“Science is the explanation of the complex by the simple”

Michael Faraday

1791

–

1867

Michael Faraday discovered electromagnetic induction, conducted pioneering experiments in optics (Faraday effect), and established fundamental principles of electrochemistry.

“Nothing is too wonderful to be true”

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Giants of science

“If I have seen further, it is by standing on the shoulders of giants”

Isaac Newton

Michael Faraday

1791

–

1867

Michael Faraday discovered electromagnetic induction, conducted pioneering experiments in optics (Faraday effect), and established fundamental principles of electrochemistry.

“Nothing is too wonderful to be true”

James Clerk Maxwell

1831

–

1879

James Clerk Maxwell formulated Maxwell’s equations, unifying electricity and magnetism and predicting electromagnetic waves

“Thoroughly conscious ignorance is the prelude to every real advance in science”

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Test your knowledge

What are electromagnetic waves, and why are they essential for understanding energy and information transmission?

Electromagnetic waves are periodic disturbances of electric and magnetic fields that propagate through space carrying energy. They do not require a material medium, so they can travel through vacuum as well as through air, water or solids. These waves cover a wide range of frequencies, from radio waves to gamma rays, and include familiar phenomena such as visible light. Their study is crucial because they explain how energy and information can be transmitted over long distances. Their interaction with matter—through absorption, reflection, refraction or scattering—is fundamental for understanding optics, telecommunications, radar systems, medical imaging and many other technologies. Electromagnetic waves form the foundation of modern communication systems and play a central role in physics, astronomy and engineering.

How is the electromagnetic spectrum organized, and what distinguishes each type of wave?

The electromagnetic spectrum includes all possible electromagnetic waves, arranged according to their frequency or wavelength. At one end are radio waves, which have low frequency and long wavelength and are used in broadcasting and communication. Next come microwaves, employed in telecommunications, radar and microwave ovens. Infrared radiation is associated with heat and is used in sensors, thermography and remote controls. Visible light is the portion detectable by the human eye and is essential for vision and optical technologies. Beyond it lies ultraviolet radiation, which has higher energy and is used in sterilization and atmospheric studies. X‑rays, with even higher energy, can penetrate materials and are vital in medicine and security. Gamma rays have the highest energy and are used in nuclear physics, astrophysics and medical treatments. Each region of the spectrum has unique properties and applications.

What are electromagnetic waves in simple terms?

They are waves made of electric and magnetic fields that move through space carrying energy. They do not need air or any material to travel, which is why sunlight reaches Earth through the vacuum of space. Electromagnetic waves include visible light, radio waves, X‑rays and many others. Thanks to them we can use Wi‑Fi, listen to the radio, see medical images or simply see the world around us. They are essential in everyday life and modern technology.

What is the electromagnetic spectrum, and what is it used for?

The electromagnetic spectrum is the complete range of all electromagnetic waves, arranged from the lowest frequencies (radio waves) to the highest energies (gamma rays). Each type of wave has different uses: radio waves for communication, infrared for sensors, visible light for vision, X‑rays for medical imaging and gamma rays for studying high‑energy processes. Understanding the spectrum helps us choose the right type of wave for each application.

How do electromagnetic waves travel, and what happens when they pass through different materials?

In a vacuum, electromagnetic waves travel at the speed of light without losing energy. When they pass through materials such as air, water or glass, they may change speed and direction. This causes phenomena like refraction, reflection or scattering. They can also weaken, a process called attenuation. This explains why some waves travel long distances, like radio waves, while others are absorbed quickly, like infrared in water. These effects are important for understanding antennas, fiber optics, radar and communication systems.