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Electromagnetism 101 | National Geographic

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electromagnetic spectrum - Google Search

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Introduction to the Electromagnetic Spectrum - NASA Science

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What is Electromagnetic energy? Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and a…

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All about the different kinds of waves in the EMS.

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Physics for Kids: Types of Electromagnetic Waves

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Kids learn about the types of electromagnetic waves in the science of physics including microwaves, infrared, ultraviolet, radio, x-rays, and gamma rays.

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The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.

You know more about the electromagnetic spectrum than you may think. The image below shows where you might encounter each portion of the EM spectrum in your day-to-day life.

Is a radio wave the same as a gamma ray?

Are radio waves completely different physical objects than gamma-rays? They are produced in different processes and are detected in different ways, but they are not fundamentally different. Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation.

Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each traveling in a wave-like pattern at the speed of light. Each photon contains a certain amount of energy. The different types of radiation are defined by the the amount of energy found in the photons. Radio waves have photons with low energies, microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and, the most energetic of all, gamma-rays.

Measuring electromagnetic radiation

Electromagnetic radiation can be expressed in terms of energy, wavelength, or frequency. Frequency is measured in cycles per second, or Hertz. Wavelength is measured in meters. Energy is measured in electron volts. Each of these three quantities for describing EM radiation are related to each other in a precise mathematical way. But why have three ways of describing things, each with a different set of physical units?

The short answer is that scientists don't like to use numbers any bigger or smaller than they have to. It is much easier to say or write "two kilometers" than "two thousand meters." Generally, scientists use whatever units are easiest for the type of EM radiation they work with.

Astronomers who study radio waves tend to use wavelengths or frequencies. Most of the radio part of the EM spectrum falls in the range from about 1 cm to 1 km, which is 30 gigahertz (GHz) to 300 kilohertz (kHz) in frequencies. The radio is a very broad part of the EM spectrum.

Infrared and optical astronomers generally use wavelength. Infrared astronomers use microns (millionths of a meter) for wavelengths, so their part of the EM spectrum falls in the range of 1 to 100 microns. Optical astronomers use both angstroms (0.00000001 cm, or ) and nanometers (0.0000001 cm, or ). Using nanometers, violet, blue, green, yellow, orange, and red light have wavelengths between 400 and 700 nanometers. (This range is just a tiny part of the entire EM spectrum, so the light our eyes can see is just a little fraction of all the EM radiation around us.)

The wavelengths of ultraviolet, X-ray, and gamma-ray regions of the EM spectrum are very small. Instead of using wavelengths, astronomers that study these portions of the EM spectrum usually refer to these photons by their energies, measured in electron volts (eV). Ultraviolet radiation falls in the range from a few electron volts to about 100 eV. X-ray photons have energies in the range 100 eV to 100,000 eV (or 100 keV). Gamma-rays then are all the photons with energies greater than 100 keV.

Show me a chart of the wavelength, frequency, and energy regimes of the spectrum

Why do we put telescopes in orbit?

Most electromagnetic radiation from space is unable to reach the surface of the Earth. Radio frequencies, visible light and some ultraviolet light makes it to sea level. Astronomers can observe some infrared wavelengths by putting telescopes on mountain tops. Balloon experiments can reach 35 km above the surface and can operate for months. Rocket flights can take instruments all the way above the Earth's atmosphere, but only for a few minutes before they fall back to Earth.

For long-term observations, however, it is best to have your detector on an orbiting satellite and get above it all!

Updated: March 2013

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The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes - the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation.

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Science Sparks: WHAT IS THE ELECTROMAGNETIC SPECTRUM?

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Science Sparks: WHAT IS THE ELECTROMAGNETIC SPECTRUM?

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A nice and basic explanation of the EMS. Uses some great visuals.

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The electromagnetic spectrum is the name for the different forms of light that are given off by objects in the Universe.

Radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays are all types of light, but with different energies!

The different types of light have different wavelengths.

What is wavelength?

Wavelength is the length of one wave. The longer the wavelength the less energy the waves have.

Radio waves have a wavelength that is a similar size to a building, while x rays have a wavelength the size of an atom! That's a big difference!

Gamma rays have the shortest wavelength and the most energy. They are also the most ionising.

Where do the different types of light in the electromagnetic spectrum come from?

Gamma rays and x-rays - these can come from natural sources such as radioactive elements but can also be man made.

Ultraviolet radiation - the Sun

Visible light - the Sun, lightbulbs

Infrared radiation - the Sun, people

Microwaves - microwaves occur naturally but can also be man-made like those used in microwave ovens.

Radio waves - radio waves are produced when an alternating current flows in an aerial.

Where is electromagnetic radiation used?

Where are gamma rays used?

Gamma rays kill microbes so can be used for sterilisation of objects and food. They are also used for cancer treatments and for medical imaging.

Where are x-rays used?

X-rays are used to view inside objects and materials. You've probably seen an x-ray scanner at an airport that looks for metal objects and if you've ever broken a bone, you may have had an x-ray. X-rays are transmitted by skin but absorbed by denser materials such as bone.

Where is infrared radiation used?

Infrared radiation is used in heaters and infrared cameras for thermal imaging.

Infrared can be used to transfer information between electronic devices and is used in TV remote controls.

Where is UV light used?

UV light is used in fluorescent lights and sometimes for sterilising water.

What's the difference between frequency and wavelength?

Frequency is the number of waves that pass a point each second. Wavelength is the length of one wave.

The longer the wavelength the lower the frequency.

What is ionising radiation?

Ionising radiation can remove an electron from an atom or molecule. These atoms or molecules are then said to be ionised and are unstable.

Gamma Rays, X rays and some types of UV radiation are ionising.

Ionising radiation can lead to changes in the DNA of a cell.

Electromagnetic Spectrum Facts

We can only see visible light.

Different colours of visible light have different wavelenghts.

Gamma rays and x-rays pass through the body which make them ideal for medical imaging.

Electromagnetic waves are transverse waves. They vibrate at 90 degrees to the direction the wave travels.

There are 7 different types of electromagnetic radiation but they merge together to form a spectrum.

The higher the frequency of the EM wave the more dangerous it is to humans.

Radio waves are not absorbed by the body.

Most of the UV radiation from the Sun is absorbed by the Earth's atmosphere, but some is absorbed by the skin where is can cause damage to cells on the surface.

All types of waves in the electromagnetic spectrum travel at the speed on light.

Last Updated on July 18, 2022 by Emma Vanstone

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The electromagnetic spectrum is the name for the different forms of light that are given off by objects in the Universe. Radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays are all types of light, but with different energies! The different types of light have different wavelengths.