Many objects and devices send out electromagnetic waves. These are mostly invisible to the human eye. But we can recognize their existence all around us every day – from powering appliances we use, to making the colors of a rainbow.

These pages aim to help you understand more about the basic science of electromagnetic waves and how they make mobile phones work.

What are radio waves?

Electric and magnetic fields are fundamental forces in nature. Together they create invisible electromagnetic waves which pass through the environment - like ripples on the surface of water.

Eletromagnetic waves have different properties and uses, depending on their wavelength. Radio waves occur within a specific range of wavelengths, and are useful for transmitting sound and digital signals.

• Electricity and radio waves can be used to power man-made devices
• We see different frequencies of visible light waves as different colors
• X-rays can show inside some solid objects

Lower frequency waves such as microwaves cannot change the structure of biological material, but can have a heating effect. This is called non-ionizing radiation. Higher frequency waves like x-rays can change the structure of biological material. This is called ionizing radiation. Radio devices emit non-ionizing radiation.

Find out more about other sources of electromagnetic waves.